VICP Registry Case Source Bundle Canonical URL: https://vicp-registry.org/case/USCOURTS-cofc-1_21-vv-01513 Package ID: USCOURTS-cofc-1_21-vv-01513 Petitioner: Portia Exum Filed: 2021-06-25 Decided: 2025-09-17 Vaccine: Tdap Vaccination date: 2018-08-20 Condition: autoimmune hepatitis Outcome: denied Award amount USD: AI-assisted case summary: Portia Exum, a 30-year-old adult, received Tdap and MMR vaccines on August 20, 2018. She later developed autoimmune hepatitis (AIH), alleging the vaccines caused her condition. Her symptoms, including fatigue and nausea, began approximately two months after vaccination, with elevated liver enzymes detected on October 26, 2018. She received treatment for AIH, which included medication and monitoring. Petitioner presented expert testimony from Dr. Robert Gish, who theorized that the vaccines could have caused AIH through molecular mimicry and other immune activation mechanisms, citing various case reports. Respondent presented expert testimony from Dr. Jeffrey Crippin and Dr. Andrew MacGinnitie, who argued that the vaccines were not the cause of her AIH, pointing to other potential factors such as her travel history, anti-malarial medication, prior Epstein-Barr virus infection, and the idiopathic nature of AIH. The Chief Special Master initially denied her claim, finding she failed to establish causation. This decision was reviewed by the Court of Federal Claims, which remanded the case for further explanation. On remand, the Chief Special Master again denied the claim, concluding that Petitioner failed to establish that the vaccines could cause AIH (Althen prong one) and that the evidence did not demonstrate the vaccines actually caused her AIH (Althen prong two), citing the lack of contemporaneous evidence of a vaccine reaction, the presence of confounding factors, and the persuasive testimony of Respondent's experts. The Court of Federal Claims affirmed the denial, finding the Chief Special Master's reasoning to be well-supported and not arbitrary or capricious. Therefore, Portia Exum was not entitled to compensation. Theory of causation field: Tdap and influenza vaccines on August 20, 2018, age about 30, alleged to cause autoimmune hepatitis with onset/abnormal liver presentation about 68 days later. DENIED after extensive review proceedings. Petitioner Portia Exum argued vaccination triggered autoimmune hepatitis through immune activation/molecular mimicry. Respondent disputed the medical theory, temporal relationship, and logical sequence. Chief Special Master Corcoran denied entitlement; Judge Armando O. Bonilla and later review proceedings addressed the special master's reasoning and ultimately left petitioner without compensation. Latest substantive public review opinion in this staged set was filed September 2025. No injury compensation awarded. Public staged source text: ================================================================================ DOCUMENT 1: USCOURTS-cofc-1_21-vv-01513-cl-extra-10735202 Date issued/filed: 2024-05-28 Pages: 1 Docket text: Supplementary opinion from CourtListener cluster 10268612 -------------------------------------------------------------------------------- In the United States Court of Federal Claims OFFICE OF SPECIAL MASTERS No. 21-1513V (not to be published) ************************* Chief Special Master Corcoran * PORTIA EXUM, * * Filed: May 2, 2024 Petitioner, * v. * * SECRETARY OF HEALTH * AND HUMAN SERVICES, * * Respondent. * * ************************* Amber Wilson, Wilson Science Law, Washington, DC for Petitioner. Lauren Kells, U.S. Dep’t of Justice, Washington, DC, for Respondent. DECISION GRANTING IN PART INTERIM AWARD OF ATTORNEY’S FEES AND COSTS 1 On June 25, 2021, Portia Exum filed a petition for compensation under the National Vaccine and Injury Compensation Program (the “Vaccine Program”). 2 (ECF No. 1) (“Pet.”) at 1. Petitioner alleges that she suffered autoimmune hepatitis and “chronically elevated liver serum enzymes” as a result of the measles-mumps-rubella and the tetanus-diphtheria-acellular pertussis vaccines she received on August 20, 2018. Id. at 1, 4. A two-day entitlement hearing was held in the matter on March 7-8, 2024, and resolution of the claim is still pending. 1 Although I have not formally designated this Decision for publication, it will nevertheless be posted on the United States Court of Federal Claims website, in accordance with the E-Government Act of 2002, 44 U.S.C. § 3501 (2012). As provided by 42 U.S.C. § 300aa-12(d)(4)(B), however, the parties may object to the Decision’s inclusion of certain kinds of confidential information. Specifically, under Vaccine Rule 18(b), each party has fourteen days within which to request redaction “of any information furnished by that party: (1) that is a trade secret or commercial or financial in substance and is privileged or confidential; or (2) that includes medical files or similar files, the disclosure of which would constitute a clearly unwarranted invasion of privacy.” Vaccine Rule 18(b). Otherwise, the whole Decision will be available to the public. Id. 2 The Vaccine Program comprises Part 2 of the National Childhood Vaccine Injury Act of 1986, Pub. L. No. 99-660, 100 Stat. 3758, codified as amended at 42 U.S.C. §§ 300aa-10 through 34 (2012) [hereinafter “Vaccine Act” or “the Act”]. Individual section references hereafter will be to Section 300aa of the Act (but will omit the statutory prefix). 1 Petitioner has now filed a motion for an interim award of attorney’s fees and costs. Motion, dated April 8, 2024 (ECF No. 65) (“Int. Fees Mot.”). Petitioner requests a total of $214,267.64, reflecting $194,777.77 in fees and costs incurred for the services of attorney Amber Wilson, plus $19,489.87 in fees and costs incurred for the services of co-counsel Gary Krochmal. Int. Fees Mot. at 2–3. Respondent reacted to the final fees request on April 22, 2024. Response, dated April 22, 2024 (ECF No. 66) (“Response”). Respondent has contested the fees award on the grounds of reasonable basis, which I discuss below. Response at 15–18. In reaction, Petitioner filed a reply. Reply, dated April 29, 2024 (ECF No. 67) (“Reply”). For the reasons set forth below, I hereby GRANT in part Petitioner’s motion, awarding fees and costs in the total amount of $213,367.64. ANALYSIS I. Petitioner’s Claim has Reasonable Basis Although the Vaccine Act only guarantees a fees award to successful petitioners, a special master may also award fees and costs in an unsuccessful case if: (1) the “petition was brought in good faith”; and (2) “there was a reasonable basis for the claim for which the petition was brought.” Section 15(e)(1). I have in prior decisions set forth at length the criteria to be applied when determining if a claim possessed “reasonable basis” sufficient for a fees award. See, e.g., Sterling v. Sec’y of Health & Hum. Servs., No. 16-551V, 2020 WL 549443, at *4 (Fed. Cl. Spec. Mstr. Jan. 3, 2020). Importantly, establishing reasonable basis does not automatically entitle an unsuccessful claimant to fees, but is instead a threshold obligation; fees can still thereafter be limited, if unreasonable, or even denied entirely. Claims that are still in the process of being resolved are subject to the reasonable basis analysis, given that the claim has not yet been deemed “successful.” See Bush v. Sec'y of Health & Hum. Servs., No. 15-476V, 2016 WL 3905608 (Fed. Cl. Spec. Mstr. June 17, 2016) (denying interim fees request due to lack of reasonable basis). A claim’s reasonable basis 3 must be demonstrated through some objective evidentiary showing. Cottingham v. Sec’y of Health & Hum. Servs., 971 F.3d 1337, 1344 (Fed. Cir. 2020) (citing Simmons v. Sec’y of Health & Hum. Servs., 875 F.3d 632, 635 (Fed. Cir. 2017)). This objective inquiry is focused on the claim—counsel’s conduct is irrelevant (although it may bulwark good faith). Simmons, 875 F.3d at 635. In addition, reasonable basis inquiries are not static—they evaluate not only what was known at the time the petition was filed, but also take into account what is learned about the evidentiary support for the claim as the matter progresses. 3 Because this claim’s good faith is not in dispute, I do not include a discussion of the standards applicable to that fees prong. 2 Perreira v. Sec’y of Health & Hum. Servs., 33 F.3d 1375, 1377 (Fed. Cir. 1994) (upholding the finding that a reasonable basis for petitioners’ claims ceased to exist once they had reviewed their expert's opinion, which consisted entirely of unsupported speculation). As a result, a claim can “lose” reasonable basis over time. The standard for finding the existence of reasonable basis is lesser (and thus inherently easier to satisfy) than the preponderant standard applied when assessing entitlement, as cases that fail can still have sufficient objective grounding for a fees award. Braun v. Sec’y of Health & Hum. Servs., 144 Fed. Cl. 72, 77 (2019). The Court of Federal Claims has affirmed that “[r]easonable basis is a standard that petitioners, at least generally, meet by submitting evidence.” Chuisano v. Sec’y of Health & Hum. Servs., 116 Fed. Cl. 276, 287 (Fed. Cl. 2014) (internal quotations omitted) (affirming special master). The factual basis and medical support for the claim is among the evidence that should be considered. Carter v. Sec’y of Health & Hum. Servs., 132 Fed. Cl. 372, 378 (Fed. Cl. 2017). Under the Vaccine Act, special masters have “maximum discretion” in applying the reasonable basis standard. See, e.g., Silva v. Sec’y of Health & Hum. Servs., 108 Fed. Cl. 401, 401–02 (Fed. Cl. 2012). 4 Respondent maintains that no fees award is appropriate in this case. First, he noted that none of Petitioner’s medical providers attribute her illness to the MMR or Tdap vaccines, nor did they even discuss vaccine causation in treater notes. Response at 15. Second, Petitioner had a number of other medical conditions that could have caused her symptoms, including gastrointestinal issues and potential diseases contracted during travel. Id. at 16. Respondent also highlights Petitioner’s use of malaria medication and over-the-counter supplements. Id. And he criticizes the proposed causal theory addressed at hearing, noting that it relies mostly on case reports (a kind of evidence given limited weight in the Program) which have not been shown to be pertinent to the vaccines Petitioner received, or even her alleged injury. Id. at 17. Thus, Respondent argues, Petitioner has failed to provide “more than a scintilla” of evidence backing her claim, and no reasonable basis existed when the claim was filed. Id. at 15, 17. In reaction, Petitioner contends that the general fact of her injury is not contested, and that her medical records provide objective support for the claim. Reply at 5–6. She also notes that prior comparable cases have resulted in favorable entitlement determinations (and therefore reasonable basis was assumed), even without the support of an expert report, which Petitioner has provided here. Id. at 4, 6. Finally, she argues that a denial of interim fees would frustrate the objectives of the Vaccine Act. Id. at 9. Although I have not yet resolved entitlement in this case, I find the matter possesses 4 See also Chuisano, 116 Fed. Cl. at 285 (cautioning against rigid rules or criteria for reasonable basis because they would subvert the discretion of special masters and stating that an amorphous definition of reasonable basis is consistent with the Vaccine Act as a whole). 3 sufficient objective basis to justify a fees and costs award. A number of objective medical records support Petitioner’s claim. And Respondent’s arguments against the claim’s preponderant sufficiency do not equate to a showing of the lack of minimal objective support that reasonable basis requires. Indeed, I allowed a trial to proceed because I could not conclude that the claim had no likelihood of success, given the existence of fairly-disputed legal and factual questions. Thus (and in light of the low bar to a reasonable basis determinations generally), I find that sufficient objective proof exists for a favorable reasonable basis finding. And the other indicia I usually apply when determining whether to allow an interim award (such as the total fees incurred, or whether a trial has been held) are also met. II. Calculation of Fees Determining the appropriate amount of the fees award is a two-part process. The first part involves application of the lodestar method—“multiplying the number of hours reasonably expended on the litigation times a reasonable hourly rate.” Avera v. Sec’y of Health & Hum. Servs., 515 F.3d 1343, 1347–48 (Fed. Cir. 2008) (quoting Blum v. Stenson, 465 U.S. 886, 888 (1984)). The second part involves adjusting the lodestar calculation up or down to take relevant factors into consideration. Id. at 1348. This standard for calculating a fee award is considered applicable in most cases where a fee award is authorized by federal statute. Hensley v. Eckerhart, 461 U.S. 424, 429–37 (1983). An attorney’s reasonable hourly rate is determined by the “forum rule,” which bases the proper hourly rate to be awarded on the forum in which the relevant court sits (Washington, D.C., for Vaccine Act cases), except where an attorney’s work was not performed in the forum and there is a substantial difference in rates (the so-called “Davis exception”). Avera, 515 F.3d at 1348 (citing Davis Cty. Solid Waste Mgmt. & Energy Recovery Special Serv. Dist. v. U.S. Envtl. Prot. Agency, 169 F.3d 755, 758 (D.C. Cir. 1999)). A 2015 decision established the hourly rate ranges for attorneys with different levels of experience who are entitled to the forum rate in the Vaccine Program. See McCulloch v. Sec’y of Health & Hum. Servs., No. 09-293V, 2015 WL 5634323, at *19 (Fed. Cl. Spec. Mstr. Sept. 1, 2015). Petitioner requests the following rates for her attorneys, based on the years work was performed: 2020 2021 2022 2023 2024 Amber Wilson $345.00 $378.00 $427.00 $454.00 $479.00 Gary Krochmal -- -- -- $505.00 $553.00 Paralegal $150.00 $150.00 -- -- -- 4 Final Fees Motion at 4–12, 29–39, 52. Ms. Wilson practices in Washington, DC—a jurisdiction that has been deemed “in forum.” Mr. Krochmal practices in Farmington, MI, which has also been deemed “in forum.” Accordingly, both are entitled to forum rates as established in McCulloch. See Stuart v. Sec'y of Health & Hum. Servs., No. 16-940V, 2022 WL 176145 (Fed. Cl. Spec. Mstr. Jan. 5, 2022); Kraemer v. Sec'y of Health & Human Servs., No. 18-1631V, 2020 WL 4598754 (Fed. Cl. Spec. Mstr. Aug. 4, 2020). The rates requested for Ms. Wilson and Mr. Krochmal are also consistent with what has previously been awarded for their work, in accordance with the Office of Special Masters’ fee schedule. 5 Rivera v. Sec'y of Health & Hum. Servs., No. 22-1310V, 2023 WL 4312968 (Fed. Cl. Spec. Mstr. June 6, 2023); Finn v. Sec'y of Health & Hum. Servs., No. 20-1897V, 2023 WL 6465152 (Fed. Cl. Spec. Mstr. Aug. 29, 2023). I thus find no cause to reduce them in this instance. And I deem the time devoted to the matter to be reasonable. I will therefore award all fees requested without adjustment. III. Calculation of Costs Just as they are required to establish the reasonableness of requested fees, petitioners must also demonstrate that requested litigation costs are reasonable. Presault v. United States, 52 Fed. Cl. 667, 670 (2002); Perreira v. Sec’y of Dep’t of Health & Hum. Servs., 27 Fed. Cl. 29, 34 (1992). Reasonable costs include the costs of obtaining medical records and expert time incurred while working on a case. Fester v. Sec’y of Health & Hum. Servs., No.10-243V, 2013 WL 5367670, at *16 (Fed. Cl. Spec. Mstr. Aug. 27, 2013). When petitioners fail to substantiate a cost item, such as by not providing appropriate documentation to explain the basis for a particular cost, special masters have refrained from paying the cost at issue. See, e.g., Gardner-Cook v. Sec’y of Health & Hum. Servs., No. 99-480V, 2005 WL 6122520, at *4 (Fed. Cl. Spec. Mstr. June 30, 2005). Petitioner seeks $31,196.17 in outstanding costs for Ms. Wilson’s firm, including the filing fee, medical record retrieval costs, mailing costs, scientific article access, travel costs to visit Petitioner, and the work of one expert, Dr. Robert Gish. Int. Fees Mot. at 16–31, 43–51. Dr. Gish prepared one report in this case, and testified at the hearing. He submitted four invoices, reflecting a total of $28,400 (35.25 hours at a rate of $600.00 per hour, as well as 13 hours of hearing preparation and testimony charged at a rate of $650.00 per hour, minus a $1,200.00 retainer on the total). Id. at 29–31, 51. Although the total hours Dr. Gish devoted to this matter were reasonable, he will not be awarded the increased $650 per hour fee for his hearing work, since it is not the practice of the Program (or my own) to award experts different rates for different types of work. Instead, his rate will be reduced to his regular rate of $600 per hour for that work, representing a $650.00 total reduction in his requested fees. 5 OSM Attorneys’ Forum Hourly Rate Fee Schedules, https://www.uscfc.uscourts.gov/node/2914 (last visited April 30, 2024). 5 All of the other costs are commonly incurred in the Vaccine Program, and are reasonable herein. Ms. Wilson’s requested costs shall therefore be awarded (after the aforementioned reductions specific to Dr. Gish’s work), for a total of $30,546.17. Petitioner also seeks $2,454.97 in costs for Mr. Krochmal’s firm, including the cost to travel for the in-person hearing. Int. Fees Motion at 53. These costs are reasonable and will be granted. However, Mr. Krochmal also requests $250.00 for “Postage, Photocopy, Mileage, Telephone, Fax, Etc.” Id. None of these costs have been substantiated with receipts, and it appears Ms. Wilson handled all of the postage costs in this case. Therefore, this amount will not be awarded. Mr. Krochmal will be awarded only $2,204.97 in costs. CONCLUSION Based on the foregoing, and in the exercise of the discretion afforded to me in determining the propriety of a final fees award, I GRANT Petitioner’s Motion for Attorney’s Fees and Costs in part, and award a total of $213,367.64. $194,127.77 will be awarded in the form of a check made jointly payable to Petitioner and her attorney Ms. Amber Wilson, and $19,239.87 in the form of a check made jointly payable to Petitioner and Mr. Gary Krochmal. In the absence of a motion for review filed pursuant to RCFC Appendix B, the Clerk of the Court SHALL ENTER JUDGMENT in accordance with the terms of this Decision. 6 IT IS SO ORDERED. s/ Brian H. Corcoran Brian H. Corcoran Chief Special Master 6 Pursuant to Vaccine Rule 11(a), the parties may expedite entry of judgment if (jointly or separately) they file notices renouncing their right to seek review. 6 ================================================================================ DOCUMENT 2: USCOURTS-cofc-1_21-vv-01513-1 Date issued/filed: 2024-09-25 Pages: 20 Docket text: PUBLIC DECISION (Originally filed: 08/29/2024) regarding 74 DECISION of Special Master. Signed by Chief Special Master Brian H. Corcoran. (af) Service on parties made. -------------------------------------------------------------------------------- Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 1 of 20 In the United States Court of Federal Claims OFFICE OF SPECIAL MASTERS No. 21-1513V * * * * * * * * * * * * * * * * * * * * * * * * * PORTIA EXUM, * Chief Special Master Corcoran * Petitioner, * Dated: August 29, 2024 * v. * * SECRETARY OF HEALTH AND * HUMAN SERVICES, * * Respondent. * * * * * * * * * * * * * * * * * * * * * * * * * * * Amber Diane Wilson, Wilson Science Law, Washington, DC, for Petitioner. Lauren Kells, U.S. Department of Justice, Washington, DC, for Respondent. ENTITLEMENT DECISION1 On June 25, 2021, Portia Exum filed a petition seeking compensation under the National Vaccine Injury Compensation Program (the “Vaccine Program”).2 Petitioner alleges that the tetanus-diphtheria-acellular pertussis (“Tdap”) and measles-mumps-rubella (“MMR”) vaccines she received on October 8, 2018, caused her to develop autoimmune hepatitis (“AIH”). Pet. at 1. A one-day Entitlement Hearing was held on March 7, 2024. Now, having heard the witnesses at hearing and reviewed the record, I find Petitioner is not entitled to compensation. 1 Under Vaccine Rule 18(b), each party has fourteen (14) days within which to request redaction “of any information furnished by that party: (1) that is a trade secret or commercial or financial in substance and is privileged or confidential; or (2) that includes medical files or similar files, the disclosure of which would constitute a clearly unwarranted invasion of privacy.” Vaccine Rule 18(b). Otherwise, the whole Ruling will be available to the public in its present form. Id. 2 The Vaccine Program comprises Part 2 of the National Childhood Vaccine Injury Act of 1986, Pub. L. No. 99-660, 100 Stat. 3758, codified as amended at 42 U.S.C. §§ 300aa-10 through 34 (2012) (“Vaccine Act” or “the Act”). Individual section references hereafter will be to § 300aa of the Act (but will omit that statutory prefix). Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 2 of 20 I. Factual Background Pre-Vaccination History Ms. Exum was born on January 29, 1988. Prior to the vaccinations at issue, she had a history of gastrointestinal reflux issues, small intestinal bacterial overgrowth, and kidney stones at different times. Ex. 2 at 9–12; Ex. 3 at 273–75, 265–71. Notably, during a May 2018 ER visit for kidney stones, Petitioner’s AST and ALT levels (liver enzymes) were normal. Ex. 3 at 268. Petitioner began preparing for overseas travel to Kenya and Tanzania in mid-August 2018. She received anti-malarial medication on August 17, 2018. Ex. 3 at 74. She was instructed to begin taking the medication two days before visiting areas with high risk for malaria, and to continue taking it for seven more days after leaving. Id. On August 20, 2018, she received the MMR and Tdap vaccines from her employer’s health clinic, but declined the typhoid vaccine. Id. at 72–73. Post-Vaccination Period and Symptoms Onset Petitioner traveled to Kenya and Tanzania from August 29 to September 8, 2018. Ex. 4 at 35. She reported receiving four or five bug bites during the trip. Id. Upon return, she felt fatigued, and had GERD symptoms and indigestion in late September. Id. In October 2018, she reported experiencing daily nausea. Id. On October 26, 2018, Petitioner had a routine physical for life insurance purposes that revealed elevated liver enzymes. Ex. 4 at 42 (ALT of 818 U/L with a 0-45 U/L range, AST of 546 U/L with a 0-33 U/L normal range). She followed up with a gastroenterologist on November 28, 2018, to address both the elevated liver enzymes and her ongoing nausea, as well as related GI symptoms. Ex. 3 at 280. Her abdominal exam was unremarkable, with no signs of liver enlargement or tenderness. Id. A physician’s assistant (“PA”) noted her recent abnormal liver function tests, and that Petitioner reported right-sided distress. Id. at 282. The PA recommended H. pylori testing, and that Petitioner use Pepcid and diet modifications to ease her GERD and dyspepsia. Id. Petitioner was referred to a hepatologist to have an MRI of her liver. Id. at 283. Test results two days after this visit showed even higher AST and ALT levels, but samples were negative for H. pylori. Id. at 67–69. Petitioner’s next treatment event occurred over five weeks later at a visit to her primary care physician (“PCP”) on December 7, 2018. Ex. 3 at 61. She now reported upper right quadrant abdominal pain, nausea, fatigue, and yellow eyes. Id. An abdominal exam was unremarkable, and her PCP referred her to a hepatologist. Id. at 63. She also had her inter-uterine device (“IUD”) removed on December 6, 2018, to eliminate it as a potential source of the liver issues. Id. at 242– 243. She then visited the same PCP on December 14, 2018, expressing concern for malaria or other 2 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 3 of 20 insect diseases resulting from big bites during recent travel. Id. at 57. The PCP ordered additional lab work, and referred her to an infectious disease specialist. Id. at 59. The lab work again showed elevated AST and ALT, but autoantibody testing for markers associated with AIH (anti-nuclear antibodies and anti-smooth muscle antibodies) were negative. Id. at 58. On December 19, 2019, Petitioner saw a hepatologist for her elevated liver enzymes. Ex. 3 at 232–38. She denied the presence of known risk factors for liver disease, such as alcohol consumption or IV drug use. Id. at 232. She did acknowledge taking antimalarial medication during travel, but denied taking any over-the-counter medications or supplements other than reishi mushrooms. Id. The hepatologist noted that she had no signs of decompensated liver disease, including icterus, jaundice, confusion, melena, hematochezia, hematemesis, bruising, weight loss, or abdominal swelling, and an abdominal exam was again unremarkable. Id. at 232–33, 235. But her liver MRI showed two hyper-intense lesions consistent with adenomas versus focal nodular hyperplasia (“FNH”), and asymmetric dilation of the left renal vein. Id. at 235–36. The diagnostic differential included elevated results from liver function tests (“LFTs”), and hepatic adenoma versus FNH. Id. at 237. Lab results again showed elevated LFTs, but no signs of active hepatitis infection. Ex. 8 at 73. The hepatologist ordered a liver biopsy and a repeat liver MRI with contrast in six months. Ex. 3 at 237. Petitioner underwent the liver biopsy on January 3, 2019, which expanded her differential diagnoses to “infection, the effects of medications/drugs/herbal remedies, Wilson disease and autoimmune hepatitis.” Ex. 3 at 229. The next day, she saw a hematology and oncology specialist, who stated that her elevated LFTs were due to “obvious liver disease” that he diagnosed as hepatitis. Id. at 222. Subsequent Treatment for Hepatitis On January 29, 2019, Petitioner visited an infectious disease specialist. Ex. 4 at 6. They discussed her international travel from the early fall of 2018, and she reported that she had entered bodies of water, received several insect bites, and felt extreme fatigue upon return. Id. at 8. The specialist noted she was taking a four to six-week course of prednisone. Id. at 6. He affirmed Petitioner’s hepatitis diagnosis, and ordered lab work. Id. at 8. The results revealed Petitioner had experienced an Epstein-Barr viral infection at some prior point. Id. at 12; Ex. 3 at 207. Her LFTs had improved, but were still elevated. Ex. 3 at 204. Petitioner’s LFTs thereafter trended downwards during February and March 2019, but remained elevated. Ex. 3 at 43–51. During a GI visit for reflux management in February, her treater noted that she was taking kidney-oriented medication in addition to the prednisone to treat her liver issues. Id. at 197. Her PCP later noted in April 2019 that her AIH was “improving.” Id. at 36–37. A visit to a hepatologist that same month revealed continued LFT improvement, although 3 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 4 of 20 levels remained above normal. Id. at 192–96. She also continued to report some ongoing fatigue. Id. at 34. Petitioner visited her hepatologist again in August 2019. Ex. 3 at 162–65. Her LFTs remained elevated, and the hepatologist ordered a metabolic screen to rule out hepatoxicity, and instructed her to continue with her previously-prescribed medications. Id. at 165. Labs taken shortly thereafter in September 2019 showed slightly elevated LFTs, but otherwise normal results. Id. at 20–31. By the first half of 2020, Petitioner’s liver concerns had mostly resolved, and testing began from this time to 2022 to reveal normal LFTs. Ex. 10 at 56–61; Ex. 3 at 154. A repeat liver biopsy performed in February 2021, however, showed “chronic hepatitis with minimal interface activity and mild portal fibrosis (stage 1 of 4).” Ex. 14 at 41; Ex. 15 at 83. But a hepatology follow-up in March 2022 revealed no signs of liver disease, and the latest records filed in this case show no signs of liver disease through November 2023. Ex. 14 at 36–41; Ex. 46 at 6–7. II. Hearing Witnesses A. Petitioner’s Expert – Dr. Robert Gish, M.D. Dr. Gish prepared two reports in this case. Gish First Report, dated July 11, 2022, filed as Ex. 16 (ECF No. 18-1) (“Gish First Rep.”); Gish Supplemental Report, dated March 21, 2023, filed as Ex. 38 (ECF No. 28-1). He also testified at the hearing. Dr. Gish received his M.D. from the University of Kansas, and completed his internship and residency at the University of California, San Diego. Gish CV at 3, filed on July 11, 2022, as Ex. 37 (ECF No. 20-1). He then completed a fellowship in gastroenterology and hepatology, with a special rotation in liver transplantation, at UCLA. Id. He is board-certified in internal medicine and gastroenterology, and has a separate board certification for hepatology that is part of the Certificate of Advanced Qualification in liver transplantation. Id. at 2. He is a member of multiple professional societies including the National Viral Hepatitis Round Table, the American Association for the Study of Liver Disease, and the American Liver Foundation. Id. at 4. He is a licensed physician in California, Arizona (inactive), and Nevada. Id. at 2. He has been active as a clinician and researcher for thirty-six years and has served on the editorial boards of many prestigious journals in his field, including Hepatology and the Journal of Viral Hepatitis. Gish First Report at 1. Presently, Dr. Gish is a clinical adjunct professor of medicine at the University of Nevada School of Medicine in both Reno and Las Vegas, and UCSD Skaggs School of Pharmacy and Pharmaceutical Sciences. Gish CV at 1. He is also the Medical Director of the Hepatitis B Foundation, which is the nation’s leading nonprofit research and advocacy organization for 4 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 5 of 20 hepatitis B (HBV). Id. Dr. Gish has acknowledged, however, that he is not an expert in immunology. Tr. at 90. Dr. Gish began his testimony by discussing Petitioner’s medical history prior to vaccination—which he deemed not to suggest any developing liver disease or alternative causes. Tr. at 15. For example, she had no physical exam results indicating liver issues, and four normal liver panel tests before receiving the vaccine. Id. When a patient has normal liver enzyme tests, “the chance of that person having active liver disease that is hidden in some way is extremely small.” Id. at 18. He also noted that liver disease patients typically present with symptoms like fatigue, liver pain, jaundice, rashes, and mental confusion. Id. at 19. And when reviewing Petitioner’s medical history, Dr. Gish looked for common causes of liver disease, such as alcoholism, needle sharing, high-risk sexual behavior, and having medical procedures in developing countries—but no such factors were evident. Id. at 19–20. Dr. Gish further pointed out that Petitioner had tested negative for Epstein-Barr virus and Hepatitis B and C, which are significant risk factors. Id. at 22. At most, Petitioner’s receipt of anti-malarial medication before traveling to Africa was a risk factor, “but that’s typically brief, transient, and doesn’t result in autoimmune disease long- term.” Tr. at 22. He compared Petitioner’s course to that of the patient in a case report whose hepatitis presented acutely after taking an anti-malarial medication. Id.; B. Beretta-Piccoli et al., Atovaquone/Proguanil-Induced Autoimmune-Like Hepatitis, 1 Hepatology Communications 293 (2017), filed on January 2, 2023, as Ex. A Tab 10 (ECF No. 25-10) (“Beretta-Piccoli”). In contrast to Petitioner, the patient evaluated in Beretta-Piccoli displayed symptoms like jaundice and dark urine early on, which are obvious clinical signs of liver disease. Id. at 83. Further, Petitioner had stopped taking all of her medications and supplements after receiving the initial lab results in October 2018 indicating the existence of elevated liver enzymes. Id. at 80. Thus, had the two herbal supplements Petitioner had been taking caused her elevated liver enzymes, the levels should have normalized once she stopped taking them—but she continued to have elevated liver enzymes. Id. The above, plus Dr. Gish’s view that her disease onset had begun within a few weeks of vaccination, permitted him to conclude that she fit the “ideal profile” for an adverse reaction to the vaccine. Id. at 22. To explain how the vaccines Petitioner received could have caused an autoimmune form of hepatitis, Dr. Gish proposed that she had experienced an immune-mediated reaction to the measles component of the MMR vaccine (and although his theories also touched on the Tdap vaccine, he focused more on the MMR vaccine). Tr. at 38. He pointed to filed literature studying both the measles vaccine mechanism in primates, and measles-induced immune suppression in human tissue samples. Tr. at 38–42; R. Nanan et al., Measles Virus Infection Causes Transient Depletion of Activated T. Cells from Peripheral Circulation, 12 J. of Clinical Virology 201 (1999), filed on July 11, 2022, as Ex. 31 (ECF No. 19-7) (“Nanan”); T. Munyer et al., Depressed 5 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 6 of 20 Lymphocyte Function after Measles-Mumps-Rubella Vaccination, 132 J. of Infectious Diseases 75 (1975), filed on July 11, 2022, as Ex. 32 (ECF No. 19-8) (“Munyer”). Dr. Gish theorized that, in clearing the vaccine-induced measles infection from Petitioner’s body, non-measles specific immune cells were activated, and stayed chronically activated thereafter, resulting in a chronic autoimmune condition. Tr. at 46–49. In his opinion, Petitioner’s immune self-tolerance was broken due to T-cell cross reaction, resulting from the suppression of bystander immune cells by the measles virus, allowing the immune system to attack self antigens (located on the surface or in the mitochondria of liver cells). Id. at 58. This autoimmune reaction was later compounded by Petitioner’s simultaneous receipt of the Tdap vaccine. Id. at 62. Because she had received the Tdap vaccine in the past, he explained, the antigen-specific response generated by this booster vaccine may have amplified the existing response to the measles vaccine. Id. Dr. Gish claimed independent medical/scientific literature supported this aspect of his theory, but he did not specify which articles stood for the proposition. Id. Dr. Gish then briefly discussed an item of literature that he proposed was supportive of his theory. S. Subramanian et al., Postinfectious Autoimmune Hepatitis-Induced Liver Failure: A Consequence of Hepatitis A Virus Infection, 7 ACG Case Reports J. 1 (2020), filed on July 11, 2022, as Ex. 25 (ECF No. 19-1) (“Subramanian”). But he did not reference Subramanian for its primary findings (which focused on how a hepatitis A infection could secondarily result in autoimmune hepatitis), but instead on a separate item of literature it discussed, “Vento” (which Petitioner never filed in this case). In Vento, researchers followed family groups that developed autoimmune hepatitis after Hepatitis A infections. Tr. at 66–68. The results of the Vento study supported the idea that a genetic disposition made patients susceptible to AIH, and Dr. Gish felt that this in turn suggested that Petitioner was likely genetically susceptible as well. Id. at 69. But he admitted that no genetic testing had been performed that would corroborate the contention about Petitioner’s susceptibility. Id. at 96. Dr. Gish also reviewed Petitioner’s clinical course, deeming it consistent with his causal theory. Tr. at 70. In particular, he opined that Petitioner’s AIH symptoms onset began within an acceptable 10-week timeframe for an environmental trigger (in this case the vaccine). Id. He pointed to evidence of her fluctuating but elevated liver enzymes between October 2018 and January 2019 as establishing the existence of ongoing AIH, confirmed by the biopsy taken in January 2019. Id. at 70–74, 75. Thus, he concluded that “the timing of symptoms, the timing of laboratory tests, the liver biopsy, all fits a classic triggering event and onset of autoimmune disease.” Id. at 82. On cross-examination, Dr. Gish acknowledged that he has seen patients who developed AIH after traveling, and after taking herbal supplements as well. Tr. at 91–92. He denied that Petitioner’s previous small bowel overgrowth (“SIBO”) could have caused her AIH, explaining 6 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 7 of 20 that SIBO is linked to a specific type of AIH which Petitioner did not have. Id. at 94. He acknowledged that Petitioner’s AIH could have been idiopathic, and stated that an environmental trigger can typically only be identified in half of cases. Id. at 95. When asked about the molecular mimicry component of his causal theory, Dr. Gish agreed that he had not identified a specific homology between the MMR and Tdap vaccines and liver proteins. Tr. at 108. He also attempted to explain further the immune suppression mentioned in his earlier testimony and report, and how the MMR vaccine “both suppresses and activates the immune system” at the same time. Id. at 112–16. He specified that the innate immune response is suppressed, leading the adaptive immune response to compensate. Id. at 113. Concurrently, a variety of antigen-presenting cells are activated, producing “off-target effects.” Id. Then, in a genetically susceptible individual, “[y]ou end up stimulating an arm of the immune system that isn’t getting turned off. These are the T-regs that are suppressed in some ways or can’t be activated and the immune system goes down this long pathway.” Id. B. Respondent’s Experts 1. Jeffrey Crippin, M.D. - Dr. Crippin authored one report in this case, and testified at the hearing. Crippin Report, filed on October 31, 2022, as Ex. A (ECF No. 23-1). Dr. Crippin received his medical degree from the University of Kansas, and completed an internal medicine residency at Kansas University Medical Center, where he served as chief resident. Crippin CV at 1–2, filed on March 4, 2024, as Ex. E (ECF No. 56-1). He then completed a three-year fellowship in Gastroenterology and Hepatology at the Mayo Clinic, Rochester, Minnesota. Id. at 2. He currently works at the Barnes-Jewish Hospital in St. Louis, and is a Professor of Medicine at the Washington University School of Medicine. Id. at 1. He is board certified in Internal Medicine and Gastroenterology, and has received the Certificate of Added Qualification in transplant hepatology. Id. at 6–7. He has extensive experience in patients with autoimmune hepatitis, and has treated 300-400 patients with the disease over the course of his career. Crippin Report at 1. Dr. Crippin agreed with Petitioner’s AIH diagnosis, but denied that the vaccines she received were more likely than not the cause of her illness. Tr. at 123. Rather, he pointed out numerous other potential causal factors in her record, although he was unable to specify a most likely cause. Id. at 125–27. These factors included Petitioner’s international travel in the months prior to her illness, her use of anti-malarial medication and herbal supplements, and a prior history of kidney stones, an IUD, and her SIBO. Id. at 125–27, 128–29. Further, she had tested positive for Epstein-Barr virus antibodies in December 2018. Id. at 127; Ex. 3 at 207. He admitted, however, that it was impossible to determine when she had Epstein-Barr from that test—“It could have been earlier that year, it could have been five years ago.” Id. Although she experienced fatigue 7 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 8 of 20 (a symptom of the virus) upon returning from travel, she was not tested for the virus at the time. Id. at 128. He also noted that a large number of AIH cases are idiopathic, meaning that no specific trigger can be identified. Id. at 130. Dr. Crippin then discussed one of the case reports Petitioner filed, pointing out differences from Petitioner’s clinical course. Id. at 131; W. Saliba & M. Elias, Acute Hepatitis Following MMR Vaccination, 16 European J. of Internal Medicine 379 (2005), filed on July 11, 2022, as Ex. 21 (ECF No. 18-6) (“Saliba”). Saliba featured a patient who experienced acute hepatitis rather than AIH, and no liver biopsy was performed to help determine the cause. Id. at 131; The patient had also recently given birth, putting her at greater risk of viruses due to pregnancy-related immune suppression. Tr. at 131–32. Further, the Saliba patient developed symptoms of her liver illness within two weeks of vaccination, whereas Petitioner first exhibited potential symptoms no sooner than six to eight weeks after vaccination. Id. at 132. Dr. Crippin also noted that he had not been able to locate any controlled studies showing a link between AIH and either the MMR or Tdap vaccines. Tr. at 130. And he similarly was unaware of studies showing the combined administration of both vaccines at once was a risk factor for AIH. Id. at 133. On cross, he reiterated his prior testimony that he could not determine the time when Petitioner was infected with Epstein-Barr virus, and that there were no other infections noted in her records. Id. at 135. Ultimately, he declined to identify which of the various factors he deemed the most likely cause, and stated again that this could be an idiopathic case. Id. at 137–38, 140– 41. 2. Andrew MacGinnitie, M.D., Ph.D. - Dr. MacGinnitie wrote one report in this case, and testified at the hearing. MacGinnitie Report, filed October 31, 2022, as Ex. C (ECF No. 23-3) (“MacGinnitie Rep.”). Dr. MacGinnitie is the Chief of the Division of Allergy, Asthma, and Immunology at Children’s Hospital of Wisconsin, and a Professor of Pediatrics at Medical College of Wisconsin. Tr. at 142–43. He graduated from the University of Chicago Pritzker School of Medicine with both an M.D. and a Ph.D. from the Department of Pathology. MacGinnitie CV, filed on October 31, 2022, as Ex. D (ECF No. 23-4) He then completed a residency in Pediatrics in the Boston Combined Residency Program, training at Boston Children’s Hospital and Boston Medical Center, followed by an Allergy/Immunology fellowship at Boston Children’s Hospital. Id. He is board certified in both Allergy/Immunology and Pediatrics. Id. at 11. He maintains an active clinical practice seeing more than 1600 patients annually and has extensive experience in caring for children and adults with a variety of immunologic diseases, including reactions to vaccines. MacGinnitie Report at 2. Dr. MacGinnitie also performs research, and has published articles in a number of areas related to Allergy/Immunology including food allergy, vaccine reactions, and primary immunodeficiency. Id. 8 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 9 of 20 Dr. MacGinnitie opined that the vaccines Petitioner received had no relationship to her AIH. Tr. at 148. First, he criticized Dr. Gish’s reliance on case reports in the absence of epidemiological studies connecting AIH and the Tdap and MMR vaccines. Tr. at 150. In his view, case reports cannot reliably connect a vaccine to an illness because they do not provide an accurate comparison with the baseline rate of an illness in the general population. Id. Further, none of the case studies filed involved the effects of simultaneous administration of the Tdap and MMR vaccine in causing AIH. Id. at 151; see, e.g., M. van Gemeren et al., Vaccine-Related Autoimmune Hepatitis: The Same Disease as Idiopathic Autoimmune Hepatitis? Two Clinical Reports and Review, 52 Scandinavian J. of Gastroenterology 18 (2017) (combination of Tdap and hepatitis A vaccine), filed on July 11, 2022, as Ex. 26 (ECF No. 19-2); see also P. Perumalswami et al., Vaccination as a Triggering Event for Autoimmune Hepatitis, 29 Seminars in Liver Disease 331 (2009) (hepatitis A and yellow fever vaccines), filed on March 6, 2024, as Ex. 27 (ECF No. 61). At best, Saliba involved the MMR vaccine, but the injury therein was acute hepatitis rather than AIH (a chronic condition). Id. at 152; Saliba. In another, the patient received six vaccines at the same time, and although the MMR was one of them, it was impossible, in Dr. MacGinnitie’s opinion, to isolate the effects of only one or two. Id. at 152–53; G. Veerappan et al., Vaccination- Induced Autoimmune Hepatitis, 50 Digestive Diseases and Sciences 212 (2005), filed on March 5, 2024, as Ex. 24 (ECF No. 58-1). Dr. MacGinnitie next criticized Petitioner’s molecular mimicry theory. Tr. at 156. After explaining the concept briefly, he noted that Dr. Gish had not identified any specific homology (meaning molecular similarity) between the vaccines and the liver cell antigens where an autoimmune cross-reaction would begin or occur—a crucial starting point if molecular mimicry was a reasonable explanation for Petitioner’s injury. Id. at 158. Even if he had, however, it would not be sufficient to prove the theory in Dr. MacGinnitie’s view, as there is a “massive overlap between microbial and human proteins” in nature, but which does not commonly result in autoimmunity. Id. at 158. He also criticized Petitioner’s reliance on bystander activation as a disease mechanism, noting that articles filed in the case regarding AIH did not consider this to be a pathologic explanation. Id. at 160; C. Mack et al., Diagnosis and Management of Autoimmune Hepatitis in Adults and Children: 2019 Practice Guidance and Guidelines from the American Association for the Study of Liver Diseases, 72 Hepatology 671 (2020), filed on January 26, 2023, as Ex. A, Tab 1 (ECF No. 25-1). Beyond this, Petitioner had not displayed clinical signs of significant inflammation, which would have occurred shortly after vaccination had such an autoimmune response occurred. Id. at 159. Dr. MacGinnitie also addressed Petitioner’s argument that her immune system was likely suppressed by the measles vaccine, allowing an autoimmune response to occur. He noted the absence of strong evidence showing that the measles vaccine (as opposed to the wild virus) suppresses the immune system to any pathologic degree. Tr. at 162; MacGinnitie Rep. at 8–9. And 9 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 10 of 20 he deemed articles filed to support this contention as lacking in clinical value or were outdated. Id. at 162–64; Nanan (published in 1999); Munyer. Up-to-date clinical manuals relied upon by treaters, however, acknowledge the immune-suppressive nature of the wild measles virus, but not the vaccine (the receipt of which functions to prevent this immune suppression in the first place). Tr. at 165–66; AMERICAN ACADEMY OF PEDIATRICS, RED BOOK (2021): REPORT OF THE COMMITTEE ON INFECTIOUS DISEASES 503 (32d ed. 2021), filed on January 26, 2023, as Ex. C, Tab 4 (ECF No. 26-4); see also M. Mina, Measles, Immune Suppression, and Vaccination: Direct and Indirect Nonspecific Vaccine Benefits, 74 J. Infection S10, S15 (2017), filed as Ex. C., Tab 3 (ECF No. 26-3) (noting the benefit of measles vaccine in blunting the immunosuppressive character of a wild measles virus infection). He also noted that the theory did not fit how AIH occurs. Since AIH is autoimmune in character, it reflects an aberrant overstimulated/ overactive immune process—not one that has been suppressed (and thus a measles infection-like reaction might actually reduce the possibility of an autoimmune process developing). Id. at 162. Dr. MacGinnitie challenged Dr. Gish’s argument that whole cell pertussis3 could itself stimulate a class of T-helper cells (which encourage the production of certain proinflammatory cytokines)—and thus, because Petitioner had likely received the whole cell pertussis vaccine as a child, the Tdap booster she had received in 2018 might have increased the possibility of a comparable memory response. Tr. at 169. He acknowledged the importance of the relevant T- helper cells in fighting bacterial and fungal infections, but deemed the re-stimulation of them unlikely to cause autoimmune disease. Id. at 170. Thus, although Petitioner had offered a study showing that patients vaccinated with whole cell pertussis produced more inflammatory cytokines than those vaccinated with acellular pertussis, the study did not establish that the levels of produced cytokines were anywhere near levels sufficient to propagate an autoimmune inflammatory environment. Id. at 171–72; R. Antunes et al., Th1/Th17 Polarization Persists Following Whole- Cell Pertussis Vaccination Despite Repeated Acellular Boosters, 128 J. Clinical Investigation 3853 (2018), filed on July 11, 2022, as Ex. 34 (20-1). And since Petitioner had not been tested for these cytokines, it was pure speculation to propose she had possessed them in pathologic levels after vaccination. Id. at 173. Dr. MacGinnitie concluded with a brief consideration of the onset interval of one to five months Dr. Gish proposed for vaccine-induced AIH. Tr. at 174. Although he opined that case reports should carry little evidentiary weight, he noted that the case reports Dr. Gish cited showed documented hepatitis (not simply the first symptoms) had begun within a far shorter timeframe: within ten to thirty days of vaccination. Id. at 174; see, for example, T. Sasaki et al., Autoimmune Hepatitis Following Influenza Virus Vaccination: Two Case Reports, 97 Medicine 1 (2018), filed on July 11, 2022, as Ex. 28 (ECF No. 19-4) (one week onset and one month onset). Other items of 3 The now largely-discontinued DPT vaccine included whole cell pertussis, but the version administered today (Tdap) employs an acellular form of pertussis thought to be less likely to cause certain side effects. See Andreu v. Sec'y of Health & Hum. Servs., 569 F.3d 1367 n1 (Fed. Cir. 2009) for discussion of case law on the safety concerns prompting the switch to an acellular formulation. 10 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 11 of 20 literature Petitioner referenced for a shorter onset timeframe involved distinguishable diseases or other vaccines. Tr. at 175–76; L. Schonberger et al., Guillain-Barré Syndrome Following Vaccination in the National Influenza Immunization Program, United States, 1976-1977, 110 Am. J. of Epidemiology 105, filed on March 21, 2023, as Ex. 39 (ECF No. 28-2) (flu vaccine and Guillain-Barré syndrome). III. Procedural History As noted above, the case was initiated in 2021. Respondent filed his Rule 4(c) Report disputing Petitioner’s right to compensation on August 19, 2022. Expert reports were filed through the end of 2022, the trial was held in March 2024, and the matter is now ripe for resolution. IV. Applicable Legal Standards A. Petitioner’s Overall Burden in Vaccine Program Cases To receive compensation in the Vaccine Program, a petitioner must prove either: (1) that he suffered a “Table Injury”—i.e., an injury falling within the Vaccine Injury Table— corresponding to one of the vaccinations in question within a statutorily prescribed period of time or, in the alternative, (2) that his illnesses were actually caused by a vaccine (a “Non-Table Injury”). See Sections 13(a)(1)(A), 11(c)(1), and 14(a), as amended by 42 C.F.R. § 100.3; § 11(c)(1)(C)(ii)(I); see also Moberly v. Sec’y of Health & Hum. Servs., 592 F.3d 1315, 1321 (Fed. Cir. 2010); Capizzano v. Sec’y of Health & Hum. Servs., 440 F.3d 1317, 1320 (Fed. Cir. 2006).4 There is no Table injury for AIH, so Petitioner can only assert a causation-in-fact claim. For both Table and Non-Table claims, Vaccine Program petitioners bear a “preponderance of the evidence” burden of proof. Section 13(1)(a). That is, a petitioner must offer evidence that leads the “trier of fact to believe that the existence of a fact is more probable than its nonexistence before [he] may find in favor of the party who has the burden to persuade the judge of the fact’s existence.” Moberly, 592 F.3d at 1322 n.2; see also Snowbank Enter. v. United States, 6 Cl. Ct. 476, 486 (1984) (mere conjecture or speculation is insufficient under a preponderance standard). Proof of medical certainty is not required. Bunting v. Sec’y of Health & Hum. Servs., 931 F.2d 867, 873 (Fed. Cir. 1991). In particular, a petitioner must demonstrate that the vaccine was “not only [the] but-for cause of the injury but also a substantial factor in bringing about the injury.” Moberly, 592 F.3d at 1321 (quoting Shyface v. Sec’y of Health & Hum. Servs., 165 F.3d 1344, 1352–53 (Fed. Cir. 1999)); Pafford v. Sec’y of Health & Hum. Servs., 451 F.3d 1352, 1355 (Fed. Cir. 2006). A petitioner may not receive a Vaccine Program award based solely on his assertions; 4 Decisions of special masters (some of which I reference in this ruling) constitute persuasive but not binding authority. Hanlon v. Sec’y of Health & Hum. Servs., 40 Fed. Cl. 625, 630 (1998). By contrast, Federal Circuit rulings concerning legal issues are binding on special masters. Guillory v. Sec’y of Health & Hum. Servs., 59 Fed. Cl. 121, 124 (2003), aff’d 104 F. App’x. 712 (Fed. Cir. 2004); see also Spooner v. Sec’y of Health & Hum. Servs., No. 13-159V, 2014 WL 504728, at *7 n.12 (Fed. Cl. Spec. Mstr. Jan. 16, 2014). 11 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 12 of 20 rather, the petition must be supported by either medical records or by the opinion of a competent physician. Section 13(a)(1). In attempting to establish entitlement to a Vaccine Program award of compensation for a Non-Table claim, a petitioner must satisfy all three of the elements established by the Federal Circuit in Althen v. Sec'y of Health and Hum. Servs., 418 F.3d 1274, 1278 (Fed. Cir. 2005): “(1) a medical theory causally connecting the vaccination and the injury; (2) a logical sequence of cause and effect showing that the vaccination was the reason for the injury; and (3) a showing of proximate temporal relationship between vaccination and injury.” Each Althen prong requires a different showing. Under Althen prong one, petitioners must provide a “reputable medical theory,” demonstrating that the vaccine received can cause the type of injury alleged. Pafford, 451 F.3d at 1355–56 (citations omitted). To satisfy this prong, a petitioner’s theory must be based on a “sound and reliable medical or scientific explanation.” Knudsen v. Sec’y of Health & Hum. Servs., 35 F.3d 543, 548 (Fed. Cir. 1994). Such a theory must only be “legally probable, not medically or scientifically certain.” Id. at 549. Petitioners may satisfy the first Althen prong without resort to medical literature, epidemiological studies, demonstration of a specific mechanism, or a generally accepted medical theory. Andreu v. Sec’y of Health & Hum. Servs., 569 F.3d 1367, 1378–79 (Fed. Cir. 2009) (citing Capizzano, 440 F.3d at 1325–26). Special masters, despite their expertise, are not empowered by statute to conclusively resolve what are essentially thorny scientific and medical questions, and thus scientific evidence offered to establish Althen prong one is viewed “not through the lens of the laboratorian, but instead from the vantage point of the Vaccine Act’s preponderant evidence standard.” Id. at 1380. Accordingly, special masters must take care not to increase the burden placed on petitioners in offering a scientific theory linking vaccine to injury. Contreras, 121 Fed. Cl. at 245 (“[p]lausibility . . . in many cases may be enough to satisfy Althen prong one” (emphasis in original)). In discussing the evidentiary standard applicable to the first Althen prong, the Federal Circuit has consistently rejected the contention that it can be satisfied merely by establishing the proposed causal theory’s scientific or medical plausibility. See Kalajdzic v. Sec’y of Health & Hum. Servs., No. 2023-1321, 2024 WL 3064398, at *2 (Fed. Cir. June 20, 2024) (arguments “for a less than preponderance standard” deemed “plainly inconsistent with our precedent” (citing Moberly, 592 F.3d at 1322)); Boatmon v. Sec’y of Health & Hum. Servs., 941 F.3d 1351, 1359 (Fed. Cir. 2019); see also Howard v. Sec'y of Health & Hum. Servs., 2023 WL 4117370, at *4 (Fed. Cl. May 18, 2023) (“[t]he standard has been preponderance for nearly four decades”), aff’d, 2024 WL 2873301 (Fed. Cir. June 7, 2024) (unpublished). And petitioners always have the ultimate burden of establishing their overall Vaccine Act claim with preponderant evidence. W.C. v. Sec’y of Health & Hum. Servs., 704 F.3d 1352, 1356 (Fed. Cir. 2013) (citations omitted); Tarsell 12 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 13 of 20 v. United States, 133 Fed. Cl. 782, 793 (2017) (noting that Moberly “addresses the petitioner’s overall burden of proving causation-in-fact under the Vaccine Act” by a preponderance standard). The second Althen prong requires proof of a logical sequence of cause and effect, usually supported by facts derived from a petitioner’s medical records. Althen, 418 F.3d at 1278; Andreu, 569 F.3d at 1375–77; Capizzano, 440 F.3d at 1326; Grant v. Sec’y of Health & Hum. Servs., 956 F.2d 1144, 1148 (Fed. Cir. 1992). In establishing that a vaccine “did cause” injury, the opinions and views of the injured party’s treating physicians are entitled to some weight. Andreu, 569 F.3d at 1367; Capizzano, 440 F.3d at 1326 (“medical records and medical opinion testimony are favored in vaccine cases, as treating physicians are likely to be in the best position to determine whether a ‘logical sequence of cause and effect show[s] that the vaccination was the reason for the injury’”) (quoting Althen, 418 F.3d at 1280). Medical records are generally viewed as particularly trustworthy evidence, since they are created contemporaneously with the treatment of the patient. Cucuras v. Sec’y of Health & Hum. Servs., 993 F.2d 1525, 1528 (Fed. Cir. 1993). Medical records and statements of a treating physician, however, do not per se bind the special master to adopt the conclusions of such an individual, even if they must be considered and carefully evaluated. Section 13(b)(1) (providing that “[a]ny such diagnosis, conclusion, judgment, test result, report, or summary shall not be binding on the special master or court”); Snyder v. Sec’y of Health & Hum. Servs., 88 Fed. Cl. 706, 746 n.67 (2009) (“there is nothing . . . that mandates that the testimony of a treating physician is sacrosanct—that it must be accepted in its entirety and cannot be rebutted”). As with expert testimony offered to establish a theory of causation, the opinions or diagnoses of treating physicians are only as trustworthy as the reasonableness of their suppositions or bases. The views of treating physicians should be weighed against other, contrary evidence also present in the record—including conflicting opinions among such individuals. Hibbard v. Sec’y of Health & Hum. Servs., 100 Fed. Cl. 742, 749 (2011) (not arbitrary or capricious for special master to weigh competing treating physicians’ conclusions against each other), aff’d, 698 F.3d 1355 (Fed. Cir. 2012); Veryzer v. Sec’y of Dept. of Health & Hum. Servs., No. 06-522V, 2011 WL 1935813, at *17 (Fed. Cl. Spec. Mstr. Apr. 29, 2011), mot. for review den’d, 100 Fed. Cl. 344, 356 (2011), aff’d without opinion, 475 F. Appx. 765 (Fed. Cir. 2012). The third Althen prong requires establishing a “proximate temporal relationship” between the vaccination and the injury alleged. Althen, 418 F.3d at 1281. That term has been equated to the phrase “medically-acceptable temporal relationship.” Id. A petitioner must offer “preponderant proof that the onset of symptoms occurred within a timeframe which, given the medical understanding of the disorder’s etiology, it is medically acceptable to infer causation.” de Bazan v. Sec’y of Health & Hum. Servs., 539 F.3d 1347, 1352 (Fed. Cir. 2008). The explanation for what is a medically acceptable timeframe must align with the theory of how the relevant vaccine can cause an injury (Althen prong one’s requirement). Id. at 1352; Shapiro v. Sec’y of Health & Hum. Servs., 101 Fed. Cl. 532, 542 (2011), recons. den’d after remand, 105 Fed. Cl. 353 (2012), aff’d 13 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 14 of 20 mem., 503 F. Appx. 952 (Fed. Cir. 2013); Koehn v. Sec’y of Health & Hum. Servs., No. 11-355V, 2013 WL 3214877 (Fed. Cl. Spec. Mstr. May 30, 2013), mot. for rev. den’d (Fed. Cl. Dec. 3, 2013), aff’d, 773 F.3d 1239 (Fed. Cir. 2014). B. Legal Standards Governing Factual Determinations The process for making determinations in Vaccine Program cases regarding factual issues begins with consideration of the medical records. Section 11(c)(2). The special master is required to consider “all [ ] relevant medical and scientific evidence contained in the record,” including “any diagnosis, conclusion, medical judgment, or autopsy or coroner's report which is contained in the record regarding the nature, causation, and aggravation of the petitioner's illness, disability, injury, condition, or death,” as well as the “results of any diagnostic or evaluative test which are contained in the record and the summaries and conclusions.” Section 13(b)(1)(A). The special master is then required to weigh the evidence presented, including contemporaneous medical records and testimony. See Burns v. Sec'y of Health & Hum. Servs., 3 F.3d 415, 417 (Fed. Cir. 1993) (determining that it is within the special master's discretion to determine whether to afford greater weight to contemporaneous medical records than to other evidence, such as oral testimony surrounding the events in question that was given at a later date, provided that such determination is evidenced by a rational determination). As noted by the Federal Circuit, “[m]edical records, in general, warrant consideration as trustworthy evidence.” Cucuras, 993 F.2d at 1528; Doe/70 v. Sec'y of Health & Hum. Servs., 95 Fed. Cl. 598, 608 (2010) (“[g]iven the inconsistencies between petitioner's testimony and his contemporaneous medical records, the special master's decision to rely on petitioner's medical records was rational and consistent with applicable law”), aff'd, Rickett v. Sec'y of Health & Hum. Servs., 468 F. App’x 952 (Fed. Cir. 2011) (non-precedential opinion). A series of linked propositions explains why such records deserve some weight: (i) sick people visit medical professionals; (ii) sick people attempt to honestly report their health problems to those professionals; and (iii) medical professionals record what they are told or observe when examining their patients in as accurate a manner as possible, so that they are aware of enough relevant facts to make appropriate treatment decisions. Sanchez v. Sec'y of Health & Hum. Servs., No. 11–685V, 2013 WL 1880825, at *2 (Fed. Cl. Spec. Mstr. Apr. 10, 2013); Cucuras v. Sec'y of Health & Hum. Servs., 26 Cl. Ct. 537, 543 (1992), aff'd, 993 F.2d at 1525 (Fed. Cir. 1993) (“[i]t strains reason to conclude that petitioners would fail to accurately report the onset of their daughter's symptoms”). Accordingly, if the medical records are clear, consistent, and complete, then they should be afforded substantial weight. Lowrie v. Sec'y of Health & Hum. Servs., No. 03–1585V, 2005 WL 6117475, at *20 (Fed. Cl. Spec. Mstr. Dec. 12, 2005). Indeed, contemporaneous medical records are often found to be deserving of greater evidentiary weight than oral testimony—especially where such testimony conflicts with the record evidence. Cucuras, 993 F.2d at 1528; see also 14 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 15 of 20 Murphy v. Sec'y of Health & Hum. Servs., 23 Cl. Ct. 726, 733 (1991), aff'd per curiam, 968 F.2d 1226 (Fed. Cir. 1992), cert. den'd, Murphy v. Sullivan, 506 U.S. 974 (1992) (citing United States v. United States Gypsum Co., 333 U.S. 364, 396 (1947) (“[i]t has generally been held that oral testimony which is in conflict with contemporaneous documents is entitled to little evidentiary weight.”)). However, the Federal Circuit has also noted that there is no formal “presumption” that records are accurate or superior on their face to other forms of evidence. Kirby v. Sec’y of Health & Hum. Servs., 997 F.3d 1378, 1383 (Fed. Cir. 2021). There are certainly situations in which compelling oral or written testimony (provided in the form of an affidavit or declaration) may be more persuasive than written records, such as where records are deemed to be incomplete or inaccurate. Campbell v. Sec'y of Health & Hum. Servs., 69 Fed. Cl. 775, 779 (2006) (“like any norm based upon common sense and experience, this rule should not be treated as an absolute and must yield where the factual predicates for its application are weak or lacking”); Lowrie, 2005 WL 6117475, at *19 (“[w]ritten records which are, themselves, inconsistent, should be accorded less deference than those which are internally consistent”) (quoting Murphy, 23 Cl. Ct. at 733)). Ultimately, a determination regarding a witness's credibility is needed when determining the weight that such testimony should be afforded. Andreu, 569 F.3d at 1379; Bradley v. Sec'y of Health & Hum. Servs., 991 F.2d 1570, 1575 (Fed. Cir. 1993). When witness testimony is offered to overcome the presumption of accuracy afforded to contemporaneous medical records, such testimony must be “consistent, clear, cogent, and compelling.” Sanchez, 2013 WL 1880825, at *3 (citing Blutstein v. Sec'y of Health & Hum. Servs., No. 90–2808V, 1998 WL 408611, at *5 (Fed. Cl. Spec. Mstr. June 30, 1998)). In determining the accuracy and completeness of medical records, the Court of Federal Claims has listed four possible explanations for inconsistencies between contemporaneously created medical records and later testimony: (1) a person's failure to recount to the medical professional everything that happened during the relevant time period; (2) the medical professional's failure to document everything reported to her or him; (3) a person's faulty recollection of the events when presenting testimony; or (4) a person's purposeful recounting of symptoms that did not exist. La Londe v. Sec'y of Health & Hum. Servs., 110 Fed. Cl. 184, 203–04 (2013), aff'd, 746 F.3d 1334 (Fed. Cir. 2014). In making a determination regarding whether to afford greater weight to contemporaneous medical records or other evidence, such as testimony at hearing, there must be evidence that this decision was the result of a rational determination. Burns, 3 F.3d at 417. C. Analysis of Expert Testimony Establishing a sound and reliable medical theory often requires a petitioner to present expert testimony in support of his claim. Lampe v. Sec’y of Health & Hum. Servs., 219 F.3d 1357, 1361 (Fed. Cir. 2000). Vaccine Program expert testimony is usually evaluated according to the 15 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 16 of 20 factors for analyzing scientific reliability set forth in Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 594–96 (1993). See Cedillo v. Sec’y of Health & Hum. Servs., 617 F.3d 1328, 1339 (Fed. Cir. 2010) (citing Terran v. Sec’y of Health & Hum. Servs., 195 F.3d 1302, 1316 (Fed. Cir. 1999). Under Daubert, the factors for analyzing the reliability of testimony are: (1) whether a theory or technique can be (and has been) tested; (2) whether the theory or technique has been subjected to peer review and publication; (3) whether there is a known or potential rate of error and whether there are standards for controlling the error; and (4) whether the theory or technique enjoys general acceptance within a relevant scientific community. Terran, 195 F.3d at 1316 n.2 (citing Daubert, 509 U.S. at 592–95). In the Vaccine Program the Daubert factors play a slightly different role than they do when applied in other federal judicial settings, like the district courts. Typically, Daubert factors are employed by judges (in the performance of their evidentiary gatekeeper roles) to exclude evidence that is unreliable or could confuse a jury. By contrast, in Vaccine Program cases these factors are used in the weighing of the reliability of scientific evidence proffered. Davis v. Sec'y of Health & Hum. Servs., 94 Fed. Cl. 53, 66–67 (2010) (“uniquely in this Circuit, the Daubert factors have been employed also as an acceptable evidentiary-gauging tool with respect to persuasiveness of expert testimony already admitted”). The flexible use of the Daubert factors to evaluate the persuasiveness and reliability of expert testimony has routinely been upheld. See, e.g., Snyder, 88 Fed. Cl. at 742–45. In this matter (as in numerous other Vaccine Program cases), Daubert has not been employed at the threshold, to determine what evidence should be admitted, but instead to determine whether expert testimony offered is reliable and/or persuasive. Respondent frequently offers one or more experts in order to rebut a petitioner’s case. Where both sides offer expert testimony, a special master's decision may be “based on the credibility of the experts and the relative persuasiveness of their competing theories.” Broekelschen v. Sec'y of Health & Hum. Servs., 618 F.3d 1339, 1347 (Fed. Cir. 2010) (citing Lampe, 219 F.3d at 1362). However, nothing requires the acceptance of an expert's conclusion “connected to existing data only by the ipse dixit of the expert,” especially if “there is simply too great an analytical gap between the data and the opinion proffered.” Snyder, 88 Fed. Cl. at 743 (quoting Gen. Elec. Co. v. Joiner, 522 U.S. 146 (1997)); see also Isaac v. Sec'y of Health & Hum. Servs., No. 08–601V, 2012 WL 3609993, at *17 (Fed. Cl. Spec. Mstr. July 30, 2012), mot. for review den'd, 108 Fed. Cl. 743 (2013), aff'd, 540 F. App’x. 999 (Fed. Cir. 2013) (citing Cedillo, 617 F.3d at 1339). Weighing the relative persuasiveness of competing expert testimony, based on a particular expert's credibility, is part of the overall reliability analysis to which special masters must subject expert testimony in Vaccine Program cases. Moberly, 592 F.3d at 1325–26 (“[a]ssessments as to the reliability of expert testimony often turn on credibility determinations”); 16 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 17 of 20 see also Porter v. Sec'y of Health & Hum. Servs., 663 F.3d 1242, 1250 (Fed. Cir. 2011) (“this court has unambiguously explained that special masters are expected to consider the credibility of expert witnesses in evaluating petitions for compensation under the Vaccine Act”). D. Consideration of Medical Literature Both parties filed medical and scientific literature in this case, but not all such items factor into the outcome of this decision. While I have reviewed all the medical literature submitted, I discuss only those articles that are most relevant to my determination and/or are central to Petitioner’s case—just as I have not exhaustively discussed every individual medical record filed. Moriarty v. Sec’y of Health & Hum. Servs., No. 2015–5072, 2016 WL 1358616, at *5 (Fed. Cir. Apr. 6, 2016) (“[w]e generally presume that a special master considered the relevant record evidence even though he does not explicitly reference such evidence in his decision”) (citation omitted); see also Paterek v. Sec’y of Health & Hum. Servs., 527 F. App’x 875, 884 (Fed. Cir. 2013) (“[f]inding certain information not relevant does not lead to—and likely undermines—the conclusion that it was not considered”). ANALYSIS The failure to establish even one of the three Althen prongs in the context of a causation- in-fact claim is sufficient basis for a claim’s dismissal. Dobrydnev v. Sec’y of Health & Hum. Servs., 566 Fed. Appx. 976, 980 (Fed. Cir. 2014). Petitioner could not preponderantly establish prongs one and two.5 First, Petitioner has not preponderantly established that it is likely that the MMR and Tdap vaccines—alone or in combination—can cause AIH. Dr. Gish’s opinion (which goes a bit beyond his expertise in hepatologic matters and into immunology) has some reliable points in its favor, but ultimately fails to persuasively “connect the dots” into a causal explanation. His points about the immune-suppressive character of the MMR vaccine, for example, relied on a false equivalence between the impact of the measles wild virus and vaccine, attempting to treat the impact of the two as the same.6 In fact, as Dr. MacGinnitie noted, the measles vaccine’s impact is to make immune suppression less likely—and there is a contradictory quality to arguing that immune suppression 5 I thus need not also evaluate the sufficiency of Petitioner’s third prong showing under the circumstances. 6 See, e.g., Tr. at 37 (Dr. Gish responding affirmatively to the question, “[w]ould it be expected that Mrs. Exum suffered a mild vaccine strain measles infection from the administration of her vaccine?”). But this kind of argument has been rejected in the Program before. See, e.g., Snyder v. Sec'y of Health & Hum. Servs., No. 01-162V, 2009 WL 332044, at *104 (Fed. Cl. Spec. Mstr. Feb. 12, 2009) (“petitioners have failed to demonstrate that the MMR vaccine causes immunosuppression. There is no evidence that children receiving the vaccine have higher rates of infection in the months after vaccination than children who do not receive the vaccine”), mot. for review den’d, 88 Fed. Cl. 706 (2009). 17 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 18 of 20 would cause a disease reaction that occurs due to an uncontrolled immune response. He similarly made assumptions about the impact of the Tdap vaccine (and its promotion of inflammation through stimulation of T-helper cells) that rely more on supposition than independent evidence— and he could not imbue these contentions with reliability by drawing on immunologic expertise he lacks. And the idea that both vaccines administered at the same time raise the risk of an aberrant response is a barely-plausible contention that lacked corroboration from materials filed in this case. More generally, it was not shown that the vaccines at issue could likely promote an autoimmune response resulting in AIH—and consideration of the typical “building blocks” relied upon by petitioners in comparable Program cases illuminates why. Autoimmune diseases involve mistaken self-attacks propagated by antibodies generated in response to a foreign antigen that (due to molecular and/or structural similarities with a self-antigen protein) then cross-react with the self tissue, often in a chronic/persistent manner. See, e.g., Bielak v. Sec'y of Health & Hum. Servs., No. 18-761V, 2023 WL 35509, at *33 (Fed. Cl. Spec. Mstr. Jan. 3, 2023) (“[m]olecular mimicry is predominantly driven by B cell activity, occurring when antibodies are produced in response to antigenic components of the vaccine—but which (due to mimicry between the presenting vaccine antigens and self-tissues) cause harmful cross-reactions, by mistakenly attacking the self antigens”). Thus, litigants commonly attempt to show at a minimum (a) what homology might exist between a vaccine’s antigens and a self structure relevant to the situs of harm (here the liver), and (b) what evidence exists that the vaccine would cause the production of the likely pathogenic antibodies. See K.A. v. Sec'y of Health & Hum. Servs., No. 16-989V, 2022 WL 20213037, at *9 (Fed. Cl. Spec. Mstr. Apr. 18, 2022), mot. for review den’d, 164 Fed. Cl. 98 (2022), aff'd, 2024 WL 2012526 (Fed. Cir. May 7, 2024) (“[b]ecause homology is common in nature (given the total limited number of amino acids that constitute proteins), it is important to focus on homology specific to the “disease-related” situs for the cross-reactive attack”). Here, however, Dr. Gish has not made this showing—which, as Dr. MacGinnitie noted, is by itself not necessarily sufficient evidence to conclude an autoimmune process linked to vaccination has been established. And case reports (only a few of which, like Saliba, even involved a relevant vaccine) are known to be weak evidence of causation. Campbell v. Sec'y of Health & Hum. Servs., 97 Fed. Cl. 650, 668 (2011) (“‘[c]ase reports do not purport to establish causation definitively, and this deficiency does indeed reduce their evidentiary value,’ even if they should receive some weight”). Second, the record does not support the conclusion that Petitioner’s vaccinations caused her AIH. Nothing in the medical record (beyond the symptoms Petitioner began to experience post-vaccination) tends to support the conclusion that the vaccines caused her AIH—and to determine otherwise would be to elevate the temporal relationship between vaccination and injury into evidence of causation. Grant v. Sec'y of Health & Hum. Servs., 956 F.2d 1144, 1148 (Fed. Cir. 1992) (“[a] proximate temporal association alone does not suffice to show a causal link 18 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 19 of 20 between the vaccination and the injury”).7 More important are the circumstances in which Petitioner received these vaccines. While Dr. Gish did observe the absence of many risk factors for AIH relevant to Petitioner, he did not persuasively limit or exclude all of them. Petitioner’s recent post-vaccination foreign travel, plus her acknowledged receipt of anti-malarial medications and supplements, her IUD, and her Epstein-Barr infection were all reasonably-likely causal factors.8 In this context, there are too many other possible explanations to find the vaccines were a substantial factor as well (especially given the thin showing overall on the “can cause” prong)— and collectively they further undermine Petitioner’s showing. I so conclude even though I do not purport to identify what was the most likely cause of Petitioner’s AIH, based on the record before me. But even though claimants are never obligated to rule out alternative causes as part of their initial burden, special masters may of course consider evidence in the record undermining vaccine causation when evaluating whether the second Althen prong has been established. Stone v. Sec'y of Health & Hum. Servs., 676 F.3d 1373, 1380 (Fed. Cir. 2012) (“[t]he special master is entitled to consider the record as a whole...and no evidence should be embargoed from the special master's consideration simply because it is also relevant to another inquiry under the statute.”). I can thus legitimately determine vaccination was not likely causal of Petitioner’s AIH, even if I cannot conclude what was most likely causal. CONCLUSION A Program entitlement award is only appropriate for claims supported by preponderant evidence. Here, Petitioner has not made such a showing. Petitioner is therefore not entitled to compensation. In the absence of a motion for review filed pursuant to RCFC Appendix B, the Clerk of the Court SHALL ENTER JUDGMENT in accordance with the terms of this Decision.9 7 For this same reason, I do not give weight to the pre-vaccination absence of evidence of liver disease or hepatitis as proof of the vaccine’s role in causing what manifested after. The fact a claimant was not sick before the vaccination, but sick after, is simply another form of post hoc ergo propter hoc reasoning that the Program rejects. 8 At most, Dr. Gish distinguished the malarial medication as likely causal, with his arguments about the more abrupt form of AIH that seemed to be evident in Beretta-Piccoli. But his contentions about her mere cessation of these medications as undermining a causal role were unpersuasive—especially since Petitioner herein maintains a one-time receipt of two vaccines resulted in a chronic/persistent disease process. 9 Pursuant to Vaccine Rule 11(a), the parties may expedite entry of judgment if (jointly or separately) they file notices renouncing their right to seek review. 19 Case 1:21-vv-01513-EMR Document 75 Filed 09/25/24 Page 20 of 20 IT IS SO ORDERED. s/ Brian H. Corcoran Brian H. Corcoran Chief Special Master 20 ================================================================================ DOCUMENT 3: USCOURTS-cofc-1_21-vv-01513-2 Date issued/filed: 2025-03-20 Pages: 52 Docket text: **REDOCKETED 84 FOR PUBLICATION** JUDGE VACCINE REPORTED OPINION (PUBLIC VERSION) (reissued for publication of 82 JUDGE VACCINE OPINION). Signed by Judge Eleni M. Roumel. (abo) Service on parties made. -------------------------------------------------------------------------------- Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 1 of 52 In the United States Court of Federal Claims PORTIA EXUM, Petitioner, No. 21-1513V v. Filed Under Seal: February 26, 20251 SECRETARY OF HEALTH AND HUMAN SERVICES, Publication Date: March 20, 2025 Respondent. Amber D. Wilson of Wilson Science Law, Washington, DC argued for Petitioner. Mary Novakovic, United States Department of Justice, Civil Division, Torts Branch, Washington, D.C., argued for Respondent. With her on the briefs were Brian M. Boynton, Principal Deputy Assistant Attorney General, Washington, DC; C. Salvatore D’Alessio, Director, Torts Branch, Civil Division; Heather L. Pearlman, Deputy Director, Torts Branch, Civil Division; Alexis B. Babcock, Assistant Director, Torts Branch, Civil Division. MEMORANDUM AND ORDER Pending before this Court is Petitioner Portia Exum’s Motion for Review of the Chief Special Master’s decision denying her entitlement to compensation under the Vaccine Act. See Motion for Review (ECF No. 76) (Mot.);2 see Exum v. Sec’y of Health & Hum. Servs., No. 21-1513, 2024 WL 4291116 (Fed. Cl. Spec. Mstr. Aug. 29, 2024) (ECF No. 74) (Decision). Petitioner contends that the Chief Special Master erred by (i) articulating and applying an erroneous legal standard for 1 On February 26, 2025, this Court issued a sealed version of this Memorandum and Order. ECF No. 82. On March 14, 2025, the parties filed a Notice indicating they had no proposed redactions to the Memorandum and Order. ECF No. 83. Accordingly, the sealed and public versions of this Memorandum and Order are identical, except for the publication date and this footnote. 2 Citations throughout this Order correspond to the ECF-assigned page numbers, which do not always correspond to the pagination within the document. 1 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 2 of 52 Althen prong one, (ii) reaching conclusions on Althen prong two that were contrary to law, and (iii) failing to analyze Althen prong three. Mot. at 5. She urges this Court to set aside the Decision and grant entitlement, or, in the alternative, remand this matter to the Chief Special Master for further consideration under the proper standard of review. Id. Respondent Secretary of Health and Human Services urges this Court to affirm the Decision, arguing that Petitioner “has not shown that the Chief Special Master’s denial of entitlement was arbitrary, capricious, an abuse of discretion, or not in accordance with law,” and has thus not demonstrated reversible error. Response to Petitioner’s Motion for Review (ECF No. 79) (Resp.) at 8. Petitioner’s Motion is fully briefed, and this Court conducted Oral Argument on December 19, 2024. See Transcript, dated Dec. 19, 2024 (ECF No. 81) (OA Tr.). Having considered the parties’ briefs, arguments, and applicable law, Petitioner’s Motion (ECF No. 76) is GRANTED IN PART and accordingly the Decision is VACATED and REMANDED to the Chief Special Master for further action in accordance with this Memorandum and Order. BACKGROUND On June 25, 2021, Petitioner Portia Exum filed a Petition for Compensation under the National Childhood Vaccine Injury Act (Vaccine Act) for an off-table injury. Vaccine Act, 42 U.S.C. §§ 300aa-10–34; Petition for Compensation (ECF No. 1) (Pet.). Specifically, Petitioner alleged that the measles-mumps-rubella (MMR) and tetanus-diphtheria-acellular pertussis (Tdap) vaccines she received on August 20, 2018, caused her autoimmune hepatitis (AIH) and chronically elevated liver serum enzymes. Pet. ¶¶ 4, 21−22.3 To support her position, Petitioner filed expert 3 Paragraphs 21 and 22 appear on page 4 of the Petition. The numbering of paragraphs restarts at one in the paragraph following paragraph 20. For clarity, paragraph references to the Petition continue numbering the paragraphs following paragraph 20 as 21 through 30. 2 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 3 of 52 reports,4 medical literature,5 and medical records.6 Respondent filed competing expert reports7 and medical literature8 in support of its contention that Petitioner had not established that her AIH and chronically elevated liver serum enzymes were caused by the MMR and Tdap vaccines. On March 7, 2024, Chief Special Master Brian H. Corcoran held an Entitlement Hearing, in which Drs. Robert Gish, Jeffrey Crippin, and Andrew MacGinnitie testified. See generally Hr’g Tr. I. Factual Background Petitioner’s AIH diagnosis is undisputed. See Mot. at 6, 17, 20; Resp. at 9 (adopting Special Master’s factual findings); see also Exum, 2024 WL 4291116, at *5 (“Dr. Crippin [Respondent’s expert] agreed with Petitioner’s AIH diagnosis . . . .”); see also Resp. Post-Hr’g Brief (ECF No. 72) at 15 (“Respondent does not contest petitioner’s diagnosis of [AIH].”). On August 17, 2018, 4 Petitioner filed an opening and a rebuttal report from her expert, Dr. Robert Gish, along with supplemental pages and supporting exhibits. Pet. Ex. 16 (ECF No 18-1) (Gish Initial Report); Pet. Ex. 38 (ECF No. 28-1) (Gish Rebuttal Report); see also ECF No. 53-2 (Petitioner’s exhibit list). Dr. Gish testified at the Petitioner’s Entitlement Hearing (Entitlement Hearing). See Entitlement Hearing Transcript, dated Mar. 7, 2024 (ECF No. 64) (Hr’g Tr.). at 5:8−116:19. 5 See Pet. Exs. 17−23 (ECF Nos. 18-2−18-8); Pet. Exs. 25−26, 28−33 (ECF Nos. 19-1−19-2, 19- 4−19-9); Pet. Exs. 34−35 (ECF No. 20-1−20-3); Pet. Ex. 24 (ECF No. 58-1); Pet. Ex. 27; (ECF No. 61-1). 6 Petitioner filed her medical records as Exhibits 1−10. See ECF Nos. 6−7. Petitioner filed a Statement of Completion on June 30, 2021, confirming the submission of all medical records required by 42 U.S.C. § 11(c). ECF No. 8. She later filed additional medical records marked as Exhibits 14−15 (ECF No. 16-1−16-2) and Exhibit 46 (ECF No. 53). She also filed updated medical records as Exhibits 4344 (ECF No. 45-1−45-2). 7 Respondent filed one expert report from each of its two experts, Dr. Jeffrey Crippin and Dr. Andrew MacGinnitie. See Resp. Ex. A (ECF No. 23-1) (Crippin Report); Resp. Ex. C (ECF No. 23-3) (MacGinnitie Report). Both Drs. Crippin and MacGinnitie testified at Petitioner’s Entitlement Hearing. See Hr’g Tr. 117:14–141:10, 141:25−192:17. 8 See Exhibit A, Tabs 1−19 (ECF Nos. 25-1–25-19); Exhibit C, Tabs 1−19 (ECF Nos. 26-1–26- 19). 3 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 4 of 52 in preparation for a trip to Kenya and Tanzania, Petitioner received an anti-malarial medication, Malarone (Atovaquone-Proguanil), which she was instructed to begin taking beginning two days before she visited high-risk areas and continue taking until seven days after her departure. Exum, 2024 WL 4291116, at *1; Pet. Ex. 3 (ECF No. 6-3), at 74; Pet. Ex. 4 at 8 (ECF No. 6-4). On August 20, 2018,9 she received the Tdap and MMR vaccines. Exum, 2024 WL 4291116, at *1; Pet. ¶ 4; Pet. Ex. 3, at 72. She traveled to Kenya and Tanzania from August 29, 2018 through September 8, 2018, and reported receiving four or five bug bites during the trip. Exum, 2024 WL 4291116, at *1; Pet. Ex. 4, at 35. When she returned, Petitioner reported feeling “extreme fatigue,” and by late September developed gastroesophageal reflux disease (GERD) symptoms and indigestion. Exum, 2024 WL 4291116, at *1; Pet. Ex. 3, at 57; Pet. Ex. 4, at 35. By October 2018, she was experiencing daily nausea. Exum, 2024 WL 4291116, at *1; Pet. Ex. 4, at 35. On October 26, 2018—two months after receiving the Tdap and MMR vaccines—a routine physical revealed that Petitioner’s liver enzyme levels were abnormally high.10 Exum, 2024 WL 4291116, at *1; Pet. ¶ 5; Pet. Ex. 4, at 42. Prior to this test, her liver enzyme levels had been normal.11 Exum, 2024 WL 4291116, at *1; Pet. Ex. 3, at 268. 9 The first page of the Decision states that Petitioner received the vaccines on October 8, 2018. Exum, 2024 WL 4291116, at *1. However, the Petition and Petitioner’s medical records reflect that the vaccines were administered on August 20, 2018. Pet. ¶ 4; Pet. Ex. 3, at 72. 10 Petitioner’s tests for the Hepatitis C Virus and HIV during this visit were negative. Pet. Ex. 3, at 250−53. 11 Testing performed during a visit to the Emergency Room (ER) on May 16, 2018—three months before receiving the vaccines at issue—indicated that Petitioner’s liver enzyme levels were normal. Pet. Ex. 3, at 268. Lab testing performed in July 2018 also revealed normal liver enzyme levels. Pet. ¶ 9. 4 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 5 of 52 Petitioner visited a gastroenterologist on November 28, 2018, reporting elevated liver enzyme levels, nausea, and gastrointestinal (GI) symptoms. Exum, 2024 WL 4291116, at *1; Pet. Ex. 3, at 280. Her abdominal exam did not reveal any signs of liver enlargement or tenderness, although Petitioner reported that she was experiencing “right-sided distress.” Exum, 2024 WL 4291116, at *1; Pet. Ex. 3, at 282. A physician’s assistant (PA) referred Petitioner to a hepatologist for an MRI of her liver, and recommended that Petitioner undergo H. pylori testing, repeat liver function tests, take Pepcid, and make several changes to her diet. Exum, 2024 WL 4291116, at *1; Pet. Ex. 3, at 282−83. Tests results dated November 30, 2018, revealed that Petitioner’s liver enzyme levels were “extremely elevated”—even higher than her previous levels—but were negative for H. pylori. Exum, 2024 WL 4291116, at *1; Pet. Ex. 3, at 67−69. On December 6, 2018, a gynecologist removed Petitioner’s inter-uterine device (IUD) to eliminate the IUD as a possible cause of her liver issues. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 242. The following day, Petitioner visited her primary care physician (PCP), because she was reporting “intermittent nausea, right abdominal discomfort, fatigue, and that her eyes appeared yellow.” Pet ¶ 9; Pet. Ex. 3, at 61; Exum, 2024 WL 4291116, at *2. Her abdominal exam was “unremarkable” and her viral hepatitis panel came back negative,12 but her liver enzyme levels— including aspartate aminotransferase (AST) and alanine aminotransferase (ALT)—and her ferritin levels were elevated. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 62−63; Pet. Ex. 4, at 31−33. Petitioner’s PCP referred her to a hepatologist. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 62−63; Pet. Ex. 4, at 31−33. 12 Specifically, Petitioner tested negative for hepatitis A, B, and C. Her tests for antibodies including antinuclear (ANA), antismooth muscle, antimitochondrial, and antiendomysial were negative. Testing for celiac disease was negative. Her Alpha-1-antitrypsin and ceruloplasmin levels were also normal. Pet. Ex. 3, at 64−66. 5 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 6 of 52 On December 11, 2018, Petitioner had an MRI of her liver. Pet. ¶ 10; Pet. Ex. 3, at 239; Pet. Ex. 4, at 28−29. The MRI revealed two hyper-intense lesions (abnormal growth of cells or tissue in the liver) interpreted to be adenomas versus focal nodular hyperplasia (FNH), and asymmetric dilation of the left renal vein. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 235−36. Radiologists recommended that she see a hepatologist for the hepatic lesions. Pet. Ex. 4, at 28. Petitioner returned to her PCP on December 14, 2018, because she was concerned that she may have contracted malaria or another insect-borne disease during her trip to Africa. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 57. He ordered liver enzyme testing, which again revealed abnormally high levels of AST and ALT but excluded the possibility of an active hepatitis infection. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 57–58. Petitioner’s PCP also referred her to an infectious disease specialist. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 59. On December 19, 2018, 13 Petitioner was evaluated by a hepatologist, who noted that she had no signs of decompensated liver disease and that her abdominal exam did not reveal abnormalities. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 232−38. Lab results indicated that her AST and ALT levels remained elevated but did not indicate acute liver failure or an active hepatitis infection. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 232, 237; Pet. Ex. 8 (ECF No. 6-8), at 73. Her differential diagnosis noted her elevated results from liver function tests and the possibility of hepatic adenoma versus FNH. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 237. Petitioner represented that her lifestyle did not present risk factors for liver disease (e.g., alcohol consumption, drug use), but acknowledged taking anti-malarial medication during her recent trip to Kenya and Tanzania. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 232. She also reported that 13 Though the Decision states that this visit occurred on December 19, 2019, Petitioner’s medical records indicate that this hepatology visit occurred on December 19, 2018. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 232. 6 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 7 of 52 reishi mushrooms were the only other over-the-counter medication or supplement she was taking. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 232. The hepatologist recommended that Petitioner have a liver biopsy and another liver MRI in six months. Exum, 2024 WL 4291116, at *2; Pet ¶ 11; Pet. Ex. 3, at 237. Petitioner had a liver biopsy on January 3, 2019, which showed moderate interface and lobular hepatitis. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 229. The liver biopsy “raise[d] a broad differential diagnosis” consistent with infections, AIH, hepatitis secondary to the effects of medications or supplements, and Wilson’s disease (a genetic disorder that causes copper build up in the body). Pet. Ex. 3, at 229; Exum, 2024 WL 4291116, at *2. The following day, Petitioner was evaluated by a hematology and oncology specialist for evaluation of her elevated ferritin levels. Pet. Ex. 3, at 222; Pet ¶ 12; Exum, 2024 WL 4291116, at *2. He concluded that this elevated level was due to “obvious liver disease” and diagnosed her with hepatitis. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 222; Pet ¶ 12 (quoting Pet. Ex. 7 (ECF No. 6-7) at 29). A follow-up evaluation by an infectious disease specialist on January 24, 2019, confirmed Petitioner’s AIH diagnosis.14 Pet. Ex. 4, at 6−8; Exum, 2024 WL 4291116, at *2.15 During this visit, Petitioner discussed her 2018 international travel including “that she had entered bodies of water, received several insect bites, and felt extreme fatigue upon return,” and that she was taking a four- to six-week course of prednisone, which she had begun on January 19, 2019. Exum, 2024 WL 4291116, at *2; Pet. Ex. 4, at 6−8. Testing indicated that Petitioner had previously (at an undetermined time) had an Epstein-Barr viral infection and that her liver enzyme levels were 14 Specifically, the infectious disease specialist agreed that a diagnosis of AIH was most likely; the specialist spoke with a hepatitis specialist, who agreed with the diagnosis. Pet. Ex. 4, at 12−13. 15 While the Decision notes that this visit occurred on January 29, 2019, the medical records indicate that it occurred on January 24, 2019. Exum, 2024 WL 4291116, at *2; Pet. Ex. 4, at 6. 7 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 8 of 52 improving but remained abnormally high. Exum, 2024 WL 4291116, at *2; Pet. Ex. 4, at 12; Ex. 3, at 201−08. Petitioner was also treated for thrush and a kidney stone in January. Pet. ¶¶ 14−15; Pet. Ex. 3, at 52; Pet. Ex. 2, at 32−36; Pet. Ex. 4 at 12. During February and March 2019, Petitioner’s liver enzyme levels continued to improve, but remained elevated. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 42−51. Petitioner took “kidney-oriented medication” (azathioprine) and prednisone for her liver issues. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 197. In April 2019, when Petitioner returned to her PCP to discuss symptoms unrelated to her AIH (throat, thrush, chest pains), her PCP indicated that Petitioner’s AIH was “improving.” Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 36−37. Petitioner also returned to her hepatologist, reporting similar symptoms. Pet ¶ 16; Pet. Ex. 10 (ECF No. 7-1), at 6; Exum, 2024 WL 4291116, at *2. Her liver enzyme levels were improving but had not returned to normal. Exum, 2024 WL 4291116, at *2; Pet ¶ 16; Pet. Ex. 3, at 195; Pet. Ex. 10, at 10. The hepatologist recommended increasing her dose of azathioprine and decreasing her dose of prednisone. Pet. Ex. 3, at 195; Pet. Ex. 10, at 10. On August 26, 2019, Petitioner again returned to her hepatologist. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 162−65. Testing performed during that visit revealed that her liver enzyme levels were no longer improving and instead were elevated relative to previous levels,16 notwithstanding the fact that she was taking the maximum dose of azathioprine. Pet ¶ 17; Pet. Ex. 3, at 165. Her hepatologist advised that Petitioner continue taking her medication (at an increased dose) and ordered a metabolite screen to confirm that Petitioner was not suffering from hepatoxicity from the azathioprine. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 165. Testing 16 In an appointment with a nutritionist days later on August 30, 2019, the nutritionist noted that the increased liver enzyme levels correlated with Petitioner’s tapering off of her prednisone prescription. Pet. Ex. 3, at 32. 8 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 9 of 52 performed in September 2019 showed improved liver enzyme levels that were slightly elevated. Exum, 2024 WL 4291116, at *2; Pet. Ex. 3, at 20−31. On January 27, 2020, Petitioner’s hepatologist noticed that Petitioner was experiencing increased fatigue and myalgias, that her liver enzyme levels had returned to baseline, and no evidence of decompensated liver disease. Pet. ¶ 18; Pet. Ex. 10, at 56. Although her “liver concerns had mostly resolved,” Petitioner’s hepatologist instructed her to continue taking azathioprine and to have her serum enzymes tested every two to three months. Exum, 2024 WL 4291116, at *3; Pet. ¶ 18; Pet. Ex. 10, at 61. At a follow-up appointment six months later on July 27, 2020, Petitioner’s liver enzyme levels were again normal. Pet. ¶ 19; Pet. Ex. 3 at 154. She was advised to continue taking azathioprine until 18 months after her diagnosis, at which point she could stop taking the drug, assuming her liver biopsy did not indicate significant inflammation. Pet. ¶ 19; Pet. Ex. 3 at 154. Other than a February 2021 liver biopsy which revealed “chronic hepatitis with minimal interface activity and mild portal fibrosis (stage 1 of 4),” Plaintiff’s testing from mid-2020 through 2022 indicated normal liver enzyme levels. Exum, 2024 WL 4291116, at *3; Pet. Ex. 14 (ECF No. 16- 1), at 41; Pet. Ex. 15 (ECF No. 16-2) at 83, 149. A March 2022 hepatology visit did not indicate any signs of liver disease; her hepatologist noted that her liver function tests were stable and that she was not experiencing side effects related to her immunosuppression. Pet. Ex. 15, at 149; Pet. Ex. 14, at 36–41. As of November 2023, Plaintiff was not indicating any markers of liver disease. Exum, 2024 WL 4291116, at *3; Pet. Ex. 46 (ECF No. 53-1), at 6–7. Petitioner indicates that she “has had to drastically change all of her prior nutrition and lifestyle habits due to suffering from a chronic illness” and that she “continues to require regular 9 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 10 of 52 care and monitoring from specialized physicians of her [AIH] and chronically elevated liver enzymes.” Pet. ¶¶ 20−21. II. Expert Opinions In addition to the referenced medical records, the Chief Special Master reviewed four expert reports filed by three different experts: Dr. Robert Gish, Dr. Jeffrey Crippin, and Dr. Andrew MacGinnitie. See generally Gish Initial Report; Crippin Report; MacGinnitie Report; Gish Rebuttal Report. All three experts testified at the Entitlement Hearing. See generally Hr’g Tr. A. Petitioner’s Expert 1. Dr. Robert Gish The Petitioner’s expert, Dr. Robert Gish, filed an initial and supplemental report and testified as an expert witness on behalf of Petitioner. See generally Gish Initial Report; Gish Rebuttal Report; Hr’g Tr. Dr. Gish is a clinical adjunct professor of medicine at the University of Nevada School of Medicine and University of California at San Diego Skaggs School of Pharmacy and Pharmaceutical Science and serves as the Medical Director of the Hepatitis B Foundation. Gish Initial Report at 1. He actively sees patients, consults with hepatology and liver centers nationwide, and performs clinical research. Id. at 1−2. Dr. Gish’s areas of expertise include internal medicine, gastroenterology, and hepatology. Id.; Exum, 2024 WL 4291116, at *3; Hr’g Tr. at 91:11–15. Dr. Gish acknowledges that he “do[es] not identify as an immunologist.” Hr’g Tr. at 91:11–15. He testified that approximately 10 of his patients in the past 30 years have developed AIH after receiving a vaccine. Hr’g Tr. 14:8–17. One of those cases involved the MMR vaccine, and none attributed AIH to the Tdap vaccine. Id. at 14:8–17, 89:5–90:10. Dr. Gish opined that “the pathogenesis of [Petitioner’s] AIH is more probable than not attributed to the administration of her multiple vaccine dosing.” Gish Initial Rep. at 8. Dr. Gish offered several theories supporting this opinion. He theorized that the vaccines could have caused 10 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 11 of 52 Petitioner’s AIH through molecular mimicry (an antigen-specific mechanism) and through several other immune activation mechanisms. Id. at 18−22; see also Hr’g Tr. at 42:22−44:18. Dr. Gish posited that the live, attenuated measles virus in the MMR vaccine could have caused Petitioner to experience an autoimmune response resulting in AIH. Gish Initial Rep. at 18−20; Hr’g Tr. at 36:13−37:18. He relied on several studies in support of this theory, including an animal study indicating the specific immune cells that the measles vaccine targets (dendritic cells).17 Hr’g Tr. at 38:15−39:14; Pet. Ex. 33, Linda J. Rennick, et al., Live-Attenuated Measles Virus Vaccine Targets Dendritic Cells and Macrophages in Muscle of Nonhuman Primates, 89 J. Virology 2192 (2015) (ECF No. 19-9) (Rennick); Pet. Ex. 18, U. Christen & E. Hintermann, Pathogens and Autoimmune Hepatitis, 195 J. Clinical & Experimental Immunology 35 (2019) (ECF No. 18-3) (Christen & Hintermann); Pet. Ex. 29, D.A. Robertson et. al., Persistent Measles Virus Genome in Autoimmune Chronic Active Hepatitis, The Lancet (1987) (ECF No. 19-5) (Robertson); see also Gish. Initial Rep. at 10−11, 19. Further, Dr. Gish relied on a study of ex vivo human T cells to support the proposition that wild-type measles infections and the attenuated measles vaccine cause immunosuppression. Hr’g Tr. at 40:21–42:21; Pet. Ex. 31, Ralph Nanan, et al., Measles Virus Infection Causes Transient Depletion of Activated T Cells From Peripheral Circulation, 12 J. Clinical Virology 201 (1999) (ECF No. 19-7) (Nanan); see also Pet. Ex. 32, Thomas Munyer et al., Depressed Lymphocyte Function After Measles-Mumps-Rubella Vaccination, 132 J. Infectious Diseases 75 (1975) (ECF No. 19-8); Gish Initial Report at 19. Dr. Gish testified that during this immunosuppressed state, the measles infection triggers measles-specific and “bystander” immune cells. Hr’g Tr. at 42:10– 17 Dr. Gish testified that he believed Rennick was relevant to the measles component of Petitioner’s causation theory, despite that it was performed in an animal model. Hr’g Tr. at 38:15–39:14. 11 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 12 of 52 21 (discussing Gish Initial Report at 19). Using this bystander activation theory, Dr. Gish theorized that Petitioner’s MMR vaccine (which includes a live, attenuated measles vaccine infection) could have caused immunosuppression, activating both measles-specific and non-measles-specific (“bystander”) immune cells.18 Id. at 46:12−49:11; 59:24−60:2. The activation of those immune cells caused a cross-reaction of T cells, which caused a breaking of Petitioner’s self-tolerance to hepatic autoantigens. Id. at 53:21−54:12; 58:7–59:20. That, in turn, caused an autoimmune reaction. Id. at 59:15–20. According to Dr. Gish, the Tdap booster could have activated Petitioner’s memory T cells because she had previously received the tetanus and diptheria vaccines, which “amplif[ied] a normal immune response.” Id. at 62:7–63:2; Gish Initial Report at 23; Gish Rebuttal Report at 6.; see also Gish Initial Report at 10 (citing Pet. Ex. 19, Christine S. Benn et al., A Small Jab – A Big Effect: Nonspecific Immunomodulation by Vaccines, 34 Trends in Immunology 431 (2013) (ECF No. 18-4) (Benn)). He also testified that because she had previously had the Hepatitis A vaccine, memory T cells from those vaccinations could also have been the bystander immune cells that triggered an amplified immune response, noting that “there is a strong suggestive data in the medical literature” that AIH patients suffer from abnormalities associated with their T regulatory cells. Hr’g Tr. at 64:15−65:18; see also Gish Initial Report at 22 (arguing that given her Tdap and MMR vaccines “were both booster vaccines, Mrs. Exum likely suffered a sufficient immune 18 On cross-examination, Dr. Gish explained the apparently contradictory idea that suppression of the immune system can lead to AIH, a condition involving overactivation of the immune system. Hr’g Tr. at 112:7–113:10. He explained that the adaptive immune system compensates for the innate immune system, which activates a wide variety of cells, causing “off-target” effects that stimulate other parts of the immune system. Id. 12 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 13 of 52 response to increase her risk of immune dysfunction and clinical expression of autoimmune hepatitis disease.”).19 Similarly, Dr. Gish theorized that Petitioner’s prior whole cell pertussis vaccine could have caused her to display “polarization to Th1 and Th17 responses” when administrated a booster with acellular pertussis, which is one component of the Tdap vaccine. Gish Initial Report at 21−22. Citing studies from 2018 and 2010, Dr. Gish explained that Th17 cells “induce inflammation and aid B cell production of antibodies” and “are believed to play an important role in the development of a variety of autoimmune diseases.” Id. (first citing Pet. Ex. 34, Ricardo da Silva Antunes et al., Th1/Th17 Polarization Persists Following Whole-Cell Pertussis Vaccination Despite Repeated Acellular Boosters, 128 J. Clinical Investigation 3853 (2018) (ECF No. 20-1) (Antunes); and then citing Pet. Ex. 35, Fouad Lafdil et al., Th17 Cells and Their Associated Cytokines in Liver Diseases, 7 Cellular & Molecular Immunology 250 (2010) (ECF No. (20-2) (Lafdil)).20 Dr. Gish stated that medical literature supported a causal connection between the MMR and Tdap vaccines and AIH and cited numerous case reports to support his theory. Hr’g Tr. at 27:22–25; Gish Rebuttal Report at 3; see Pet. Ex. 21, Walid R. Saliba & Mazen Elias, Acute Hepatitis Following MMR Vaccination, 16 Euro. J. Internal Med. 379 (2005) (ECF No. 18-6) (Saliba & Elias); Pet. Ex. 23, PA Berry & G Smith-Laing, Hepatitis A Vaccine Associated With Autoimmune Hepatitis, 13 World J. Gastroenterology 2238 (2007) (ECF No. 18-8) (Berry & 19 See Pet. Ex. 3, at 72−73 (Petitioner’s vaccine history). As relevant here, Petitioner had previously received the DTP, Hepatitis A, Hepatitis B, MMR, Td, Tdap, Tetanus, and Yellow Fever vaccines. Id. 20 In addition to the theories described above, Dr. Gish also theorized that the aluminum adjuvant in the Tdap vaccine could have caused Petitioner’s AIH. Gish Initial Rep. at 23. However, at the Entitlement Hearing, he expressly stated that he was “setting aside” that theory. Hr’g Tr. at 60:3−15. 13 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 14 of 52 Smith-Laing); Pet. Ex. 24, Ganesh R. Veerappan et al., Vaccination-Induced Autoimmune Hepatitis, 50 Digestive Diseases & Scis. 212 (2005) (ECF No. 58-1) (Veerappan); Pet. Ex. 25, Sruthi Kapliyil Subramanian, et al., Postinfectious Autoimmune Hepatitis-Induced Liver Failure: A Consequence of Hepatitis A Virus Infection, 7 ACG Case Reps. J. 1 (2020) (ECF No. 19-1) (Subramanian); Pet. Ex. 26, Marline A J van Gemeren, et al., Vaccine-Related Autoimmune Hepatitis: The Same Disease as Idiopathic Autoimmune Hepatitis? Two Clinical Reports and Review, 52 Scandinavian J. Gastroenterology 18 (2017) (ECF No. 19-2) (van Gemeren); Pet. Ex. 27, Ponni Perumalswami, et al., Vaccination as a Triggering Event for Autoimmune Hepatitis, 29 Seminars in Liver Disease 331 (2009) (ECF No. 61) (Perumalswami); Pet. Ex. 28, Tokio Sasaki, et al., Autoimmune Hepatitis Following Influenza Virus Vaccination, Medicine, July 2018 (ECF No. 19-4) (Sasaki); Pet. Ex. 30, Giorgina Mieli-Vergani, et al., Measles and Autoimmune Chronic Active Hepatitis, The Lancet, Sept. 16, 1989, at 688 (ECF No. 19-6) (Mieli-Vergain); Pet. Ex. 45, Jorch, et al. (1984) (Jorch), cited in Institute of Medicine, Committee to Review Adverse Effects of Vaccines: Evidence and Causality 39–430 (Kathleen Stratton, et al., eds., 2012) (ECF No. 45-3) (IOM). During cross-examination, however, Dr. Gish acknowledged that the cited case reports differed from Petitioner’s case because most of the reports didn’t involve the MMR and Tdap vaccines. Hr’g Tr. at 97:14−107:22. 14 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 15 of 52 ECF No. Case Report Vaccine(s) Related Illness 18-6 Pet. Ex. 21, Saliba & Elias (2005) MMR Acute hepatitis21 Pet. Ex. 23, Berry & Smith-Laing Acute liver injury 18-8 Hepatitis A (2007) consistent w/ AIH Typhoid, Hepatitis A, Flu-like symptoms 58-1 Pet. Ex. 24, Veerappan (2005) Td, oral polio, MMR then AIH N/A; wild acute 19-1 Pet. Ex. 25, Subramanian (2020) AIH Hepatitis A infection Pet. Ex. 26, van Gemeren Hepatitis A, Hepatitis 19-2 AIH (2017) B Hepatitis A, Pet. Ex. 26, van Gemeren 19-2 diphtheria, whooping AIH (2017) cough,22 tetanus Hepatitis A and 61 Pet. Ex. 27, Perumalswami (2009) AIH yellow fever 19-4 Pet. Ex. 28, Sasaki (2018) Flu AIH Pet. Ex. 30, Mieli-Vergain et al. N/A; wild measles 19-6 AIH (1989) infection23 45-3 Pet. Ex. 45, Jorch, et al.24 MMR Meningoencephalitis 21 According to Dr. Gish’s testimony, the difference between acute hepatitis and AIH, which is chronic, is duration. Hr’g Tr. at 46:19−47:15. Acute hepatitis lasts less than six months, but chronic hepatitis persists for longer than six months. See Id. at 100:18−101:3 (Dr. Gish explaining that chronic hepatitis means the patients has “documented elevated liver tests” for six months). Although the criteria for AIH was not published until 2008—several years after the Saliba & Elias report was published—the Saliba & Elias patient’s hepatitis fit the “acute” description because “the patient’s viral hepatitis testing was negative and spontaneously the liver function tests normalized after 4 weeks.” Gish Initial Report at 14. 22 The van Gemeren case report specifically mentions that the patient was vaccinated for whooping cough, but does not clarify the specific vaccine she received. It is unclear whether this patient received the Tdap vaccine. See van Gemeren at 3; Hr’g Tr. 106:7−22. 23 While the Mieli-Vergain case report states that eight of the twelve child patients in this study “had received measles vaccination,” it does not specify which vaccine those patients received. See Mieli-Vergain at 1. The study further states: “Our data show[s] that in children [Autoimmune Chronic Hepatitis] develops despite measles vaccination, and that they have low measles antibody titres raise questions about a causative link between measles and this autoimmune condition, at least in childhood.” Id. 15 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 16 of 52 Dr. Gish theorized that when multiple vaccines are administered at the same time, the combination of a “[g]enetic predisposition to the immune stimulation of hepatitis A” and an environmental trigger (e.g., multiple vaccines administered concomitantly, plus adjuvants) “can stimulate a very robust immune response that may not be able to be brought under control until [the patient] start[s] immunosuppressants.” 25 Hr’g Tr. at 62:10–22, 69:7–14. Dr. Gish concluded that this is “a very, very good . . . theory” as to what occurred in Petitioner’s case. Id. at 62:23– 63:2. Dr. Gish acknowledged, however, that no genetic testing supported this proposition; instead, Dr. Gish based his theory, that Petitioner may have a genetic predisposition that made her susceptible to AIH, on the contention that this kind of genetic predisposition is common. Id. at 96:7−97:13 (Dr. Gish testifying that “very large studies, with thousands and thousands of patients . . . have found very powerful statistical correlations with genetic diseases, genetic abnormalities, genetic mutations”). Dr. Gish’s Initial Report also stated that Petitioner’s AIH diagnosis was “medically certain,” based on Petitioner’s medical history, medical records, and the specific sequence of events that led to her AIH. Gish Initial Report 2−7. In support, Dr. Gish discussed Petitioner’s pre-vaccination medical history, noting that prior to the vaccine, she did not appear to have liver issues, nor did her history indicate any alternative cause (other than the vaccine) for her condition. 24 This case report is mentioned in the excerpt of a publication by the Institute of Medicine filed by Petitioner as Exhibit 45. See Pet. Ex. 45, Institute of Medicine, Adverse Effects of Vaccines: Evidence and Causality (ECF No. 45-3). 25 To support his theory of genetic predisposition, Dr. Gish cited the Vento study, found in Subramanian, which followed family members of AIH patients to determine whether they would develop an AIH infection after developing a Hepatitis A infection. Because some individuals did develop AIH following this sequence of events, Dr. Gish asserted that this study supports the general idea that a “[g]enetic predisposition to the immune stimulation of hepatitis A” can contribute to AIH. Hr’g Tr. at 69:7–14. 16 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 17 of 52 Hr’g Tr. at 14:21–16:6. Specifically, he noted that her physical examinations did not indicate liver issues; her liver panel testing was normal; no lifestyle factors creating a risk of liver disease were present; and she tested negative for Hepatitis B and C. Id. at 15:17–16:6; 19:13−22:22.26 At the Entitlement Hearing, Dr. Gish addressed potential alternative causes to Petitioner’s AIH, as raised by the Respondent’s experts. Dr. Gish noted that the specialists who had treated Petitioner at the Emory Travel Clinic “concluded that her travel history [did] not suggest an alternative infectious cause to her elevated liver enzymes.” Gish Rebuttal Report at 8 (citing Pet. Ex. 4, at 7). Dr. Gish acknowledged that Petitioner’s anti-malarial medication could be a risk factor for AIH, but asserted that the timing did not support a connection, and that antimalarial medications typically do not cause long-term or chronic autoimmune conditions. Hr’g Tr. at 22:9– 14; 82:11−86:25 (discussing Resp. Ex. A, Tab 10, Benedetta Terzoli Beretta-Piccoli et al., Atovaquone/Proguanil-Induced Autoimmune-Like Hepatitis, 1 Hepatology Commc’ns 293 (2017) (ECF No. 25-10) (Beretta-Piccoli)). Further, although Petitioner was taking other supplements, the fact that her liver enzyme levels did not normalize after she stopped taking the supplements suggested to Dr. Gish that they were not the cause of her liver issues. Id. at 80:9–81:12. Relatedly, since Petitioner ceased taking reishi mushroom supplements after she learned that her liver enzyme levels were elevated, and saw no change in her liver enzyme levels as a result, Dr. Gish posited that this, too, could be eliminated as a potential cause of her AIH. Id. at 80:9–81:8. Additionally, Dr. Gish characterized the possibility that Petitioner’s history of small intestinal bacterial overgrowth (SIBO) could have contributed to her AIH as very remote, because SIBO is associated 26 Dr. Gish also noted that Petitioner’s medical records showed no positive tests for the Epstein- Barr Virus (EBV); however, Dr. Crippin noted that Petitioner’s medical records did contain evidence of a prior EBV infection at an undetermined time. Hr’g Tr. 21:19–22:4; Crippin Report at 4; Pet. Ex. 3, at 207 (positive tests for EBV Viral Capsid Antigen IGG and EBV Nuclear Antibody). 17 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 18 of 52 with a different autoimmune condition. Id. at 94:6–23. Thus, according to Dr. Gish, by process of elimination Petitioner’s MMR and Tdap vaccines causally contributed to her AIH. Id. at 22:23−23:19. In addition, citing various studies including Rennick, Saliba & Elias, and Berry & Smith- Laing, Dr. Gish concluded that “[t]he sum of clinical evidence supports that a general acceptable timeframe to infer causation is when onset of symptoms occurs within one to five months of receipt of vaccination.” Gish Initial Report at 23−24; see also Pet. Ex. 22, McMahon et al., Measles Vaccine Virus RNA in Children More than 100 Days After Vaccination, 11 Viruses 636 (2019) (ECF No. 18-7) (reporting that measles vaccine virus RNA was detected in children more than 100 days after receiving a measles-containing vaccine). According to Dr. Gish, Petitioner’s case fit within a “general acceptable timeframe to infer causation” because Petitioner’s testing showed elevated liver enzymes 68 days post-vaccination and her AIH diagnosis was confirmed five months post- vaccination. Gish Initial Report at 24; see also Gish Rebuttal Report at 9−11. In sum, Dr. Gish’s “elevator pitch” of Petitioner’s case was that the vaccine administration; the timing of her symptom onset, within 10 weeks of vaccine administration; her laboratory tests, which indicated fluctuating liver enzyme levels in 2018 through 2019; and her liver biopsy, which was consistent with recent AIH onset, taken together, indicated that the MMR and Tdap vaccines more likely than not caused her AIH. Hr’g Tr. at 70:6–77:1, 81:25–82:9. While Dr. Gish testified that AIH “needs an environmental trigger,” he acknowledged that Petitioner’s AIH could have been idiopathic (i.e., had no identifiable cause), and noted that he only identifies a trigger in approximately half of his AIH cases. Id. at 52:9−15, 95:6–22. 18 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 19 of 52 B. Respondent’s Experts 1. Dr. Jeffrey Crippin Respondent’s Expert, Dr. Jeffrey Crippin is the Marilyn Bornefield Chair in Gastrointestinal Research and Treatment, Professor of Medicine, Department of Medicine, Division of Gastroenterology at the Washington University in St. Louis School of Medicine. Crippin Report at 1. He also serves as the Vice Chair for Clinical Programs for the Department of Medicine. Id. Dr. Crippin concluded that Petitioner’s diagnosis of autoimmune hepatitis was reasonable, but challenged Dr. Gish’s conclusion that Petitioner’s Tdap and MMR vaccines led to her AIH diagnosis. Id. at 3; Hr’g Tr. at 125:9–130:12. Dr. Crippin asserted that Dr. Gish failed to acknowledge the other factors in Petitioner’s medical history that could also cause AIH, including: (1) evidence that Petitioner previously (but at an undeterminable time) had an Epstein-Barr Virus; (2) that Petitioner could have had other potential viral infections transmitted by the bug bites during her travels (although her records did not include evidence of other infections); (3) that Petitioner took an anti-malarial medication, which is associated with AIH; (4) Petitioner’s history of SIBO; (5) Petitioner’s travel to foreign countries,27 which could have increased her exposure to new bacteria; (6) that Petitioner regularly took over-the-counter supplements, including mushroom extracts; and (7) that Petitioner was using an IUD. Hr’g Tr.at 125:9−130:12, 135:13–16. In sum, Dr. Crippin posited that “there are a number of factors” that could have led to Petitioner’s AIH diagnosis, and “the interaction of multiple factors, both genetic and environmental” could have caused her AIH. Crippin Report at 4−6.28 27 Petitioner traveled to 21 countries within a four-year timeframe. Pet. Ex. 11 ¶ 16. 28 Dr. Gish conceded that “based on the case report and biological understanding of AIH pathology that other causal agents could be plausible.” Gish Rebuttal Report at 4. 19 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 20 of 52 Dr. Crippin cited numerous case reports and studies in support of the potential alternative causes of Petitioner’s AIH. See Resp. Ex. A, Tab 4, Haoran Peng et al., Autoimmune Hepatitis Following Epstein-Barr Virus Infection: A Diagnostic Dilemma, British Med. J. (2019) (ECF No. 25-4) (case report concluding that AIH has a potential association with Epstein-Barr Virus infection); Resp. Ex A, Tab 5, Claudia Caglioti et al., Chikungunya Virus Infection: An Overview, 36 New Microbiologica 211 (2013) (ECF No. 25-5) (article describing mosquito-transmitted Chikungunya virus infection); Resp. Ex. A, Tab 6, MK Huntington et al., Emerging Vector-Borne Diseases, 7 Am. Fam. Physician 551 (2016) (ECF No. 25-6) (article describing mosquito-borne viral infections such as West Nile Virus, Chikungunya, Zika, Ehrlichiosis, Rickettsial, Dengue, Lyme Disease, Malaria); Resp. Ex. A, Tab 7, A. Arturo Leis et al., West Nile Virus Infection and Myasthenia Gravis, 49 Muscle & Nerve 26 (2013) (ECF No. 25-7) (retrospective case series associating the West Nile Virus with Myasthenia gravis, an autoimmune disease); Resp. Ex. A, Tab 8, P. Karagianni et al., West Nile Virus Infection Triggering Autoimmune Encephalitis: Pathophysiological and Therapeutic Implications, 207 Clinical Immunology 97 (2019) (ECF No. 25-8) (case report associating West Nile Virus with autoimmune encephalitis); Resp. Ex. A, Tab 9, Amir Tanay, Chikungunya Virus and Autoimmunity, 29 Current Op. in Rheumatology 389 (2017) (ECF No. 25-9) (Tanay) (study associating Chikungunya virus with inflammation and immune activation “not unlike those seen in rheumatoid arthritis,” an autoimmune disease); Beretta-Piccoli (case report associating anti-malarial drug Malarone (Atovaquone-Proguanil) with AIH29); Resp. 29 As Dr. Crippin explains in his Report, the case described in Beretta-Piccoli differed from Petitioner’s because the patient in the case report took Malarone in conjunction with azithromycin, which caused jaundice and acute hepatitis, and her symptoms resolved in two weeks. Approximately a year later, the patient took Malarone again and developed AIH. See Crippin Report at 5. In other words, the patient developed AIH in response to re-administration of Malarone. However, the case report was similar to Petitioner’s case because the patient in the case report traveled to Tanzania and “need[ed] prolonged therapy with corticosteroids/prednisone.” Id. 20 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 21 of 52 Ex. A, Tab 11, Yusuke Kinashi & Koji Hase, Partners in Leaky Gut Syndrome: Intestinal Dysbiosis and Autoimmunity, 12 Frontiers in Immunology (2021) (ECF No. 25-11) (study discussing the connection between intestinal dysbiosis, leaky gut syndrome and autoimmune disease); Resp. Ex. A, Tab 12, Muhammed Yuksel et al., A Novel “Humanized Mouse” Model for Autoimmune Hepatitis and the Association of Gut Microbiota With Liver Inflammation, 62 Hepatology 1536 (2015) (ECF No. 25-12) (animal study finding that significant gut microbiota of mice with AIH was significantly different from mice without AIH30); Resp. Ex. A, Tab 13, Rui Lin et al., Abnormal Intestinal Permeability and Microbiota in Patients with Autoimmune Hepatitis, 8 Int’l J. Clinical & Experimental Pathology 5153 (2015) (ECF No. 25-13) (study associating leaky gut and microbiome imbalance with AIH); Resp. Ex. A, Tab 14, Francesca Motta et al., Mushrooms and Immunity, 117 J. Autoimmunity (2021) (ECF No. 25-14) (review of studies discussing biochemical changes induced by different mushroom compounds); Resp. Ex. A, Tab 15, Muthukumaran Jayachandran et al., A Critical Review on the Impacts of β-Glucans on Gut Microbiota and Human Health, 61 J. Nutritional Biochemistry 101 (2018) (ECF No. 25-15) (review summarizing in vitro, in vivo, and clinical studies on β-glucans and bacteria in gut microbiome); Resp. Ex. A, Tab 16, Mohamad O. Khawandanah et al., Autoimmune Hemolytic Anemia and Thrombocytopenia Attributed to an Intrauterine Contraceptive Device, 55 Transfusion 657 (2015) (ECF No. 25-16) (case report associating an IUD with Evans Syndrome manifested by autoimmune hemolytic anemia and thrombocytopenia). 30 Dr. Crippin noted in his Report that “a causative relationship was thought to deserve further investigation.” Crippin Report at 5. 21 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 22 of 52 In addition, Dr. Crippin noted that AIH is often idiopathic, and that no case reports in published medical literature support that either the MMR or Tdap vaccines—independently or together—“trigger or are associated with [AIH].” Crippin Report at 3−4, 6; Hr’g Tr. at 130:3–12, 133:7–16, 137:3−13, 140:22–141:5. He explained that the MMR vaccine has been associated with idiopathic/immune thrombocytopenia and arthritis in children, and joint pain and inflammation, but it is “is not clear” whether that is RA. Crippin Rep. at 6 (citing Resp. Ex. A, Tab 17, U Nieminen, et al., Acute Thrombocytopenic Purpura Following Measles, Mumps, and Rubella Vaccination. A Report on 23 Patients, 82 Acta Paediatr 267 (1993) (ECF No. 25-17)); Resp. Ex. A, Tab 18, C M Benjamin et al., Joint and Limb Symptoms in Children After Immunisation with Measles, Mumps, and Rubella Vaccine, 304 British Med. J. 1075 (1992) (ECF No. 25-18)). Further, case reports associated the Tdap vaccine with joint and muscle pain, a skin rash, and type 1 diabetes. Crippin Rep. at 6 (citing Resp. Ex. A, Tab 19, N. Ruhrman-Shahar et al., Autoimmune Reaction After Anti-Tetanus Vaccination—Description of Four Cases and Review of the Literature, 65 Immunological Rsch. 157 (2017) (ECF No. 25-19)). In his report and at the Entitlement Hearing, Dr. Crippin distinguished Petitioner’s case from the Saliba & Elias study. Crippin Report at 4 (citing Saliba & Elias). Dr. Crippin noted several key differences between Petitioner’s case and the patient in Saliba & Elias, including that the patient in Saliba & Elias suffered from acute hepatitis as opposed to AIH, and no liver biopsy was performed; the patient in Saliba & Elias had recently given birth, and pregnancy can cause immune suppression; and the patient in Saliba & Elias developed symptoms of her liver condition within two weeks after vaccination, whereas Petitioner’s symptom onset occurred around six to eight weeks. Hr’g Tr. 130:22−132:21. 22 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 23 of 52 2. Dr. Andrew MacGinnitie Respondent’s Second Expert, Dr. Andrew MacGinnitie is an Attending Physician as well as the Clinical Chief for the Division of Immunology at Boston Children’s Hospital overseeing clinical operations for Allergy/Immunology, Rheumatology and Dermatology, and is also an Associate Professor of Pediatrics at Harvard Medical School. MacGinnitie Report at 1. In his view, Petitioner’s AIH was “unrelated to” her MMR and Tdap vaccinations, and Dr. Gish’s theory was unreliable. Id. at 12; Hr’g Tr. at 148:4–10. Dr. MacGinnitie asserted that the case reports cited by Dr. Gish failed to establish causality between MMR, Tdap, and AIH. Hr’g Tr. at 149:17–156:18; MacGinnitie Report at 6−7. Dr. MacGinnitie noted that AIH can occur after vaccination “by coincidence.” MacGinnitie Report at 6. He further asserts that, given the widespread nature of vaccination and because vaccines are recommend for patients with AIH, the cases Dr. Gish cited were “likely coincidental.” Id. at 6–7, 11; Hr’g Tr. at 155:11–20. Further, Dr. MacGinnitie opined that case reports in general are “unable to really provide evidence of causation.” Hr’g Tr. at 150:2–3. Further, Dr. MacGinnitie challenged Dr. Gish’s molecular mimicry theory, because Dr. Gish had not identified a potential homology between the MMR and Tdap vaccines and liver antigens. MacGinnitie Report at 7 (citing Resp. Ex. C, Tab 2, Institute of Medicine, Committee to Review Adverse Effects of Vaccines: Evidence and Causality (Kathleen Stratton, et al., eds., 2012) (ECF No. 26-2))31; Hr’g Tr. at 156:4–18, 157:22–158:7. Dr. MacGinnitie also contended that Dr. Gish had failed to explain how either vaccine otherwise could have caused Petitioner’s AIH. MacGinnitie Report at 7−11. Dr. MacGinnitie further contends that the bystander activation 31 This is a different portion of the same IOM publication cited by Petitioner. See Pet. Ex. 45, IOM. 23 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 24 of 52 theory, that Dr. Gish opined would cause the relevant cross-reaction, “is not a commonly accepted mechanism of [AIH].” Hr’g Tr. at 160:11–20. With respect to Dr. Gish’s theories relating to the measles virus, Dr. MacGinnitie countered that the “[m]easles virus causes profound suppression which is not seen with vaccination.” MacGinnitie Report at 8−9 (emphasis omitted); Hr’g Tr. at 162:6–20. Although Dr. MacGinnitie agreed that the wild measles virus causes immunosuppression, he took issue with Dr. Gish’s position that the measles vaccine causes immune suppression. MacGinnitie Report at 8. Contrary to Dr. Gish’s assertion that “it is well understood” the measles vaccine induces temporary immunosuppression, Dr. MacGinnitie opined that “more contemporary literature stress the need for measles vaccination to prevent the immunosuppression triggered by wild-type infection.” Id. (emphasis added). Dr. MacGinnitie noted that the Nanan and Munyer articles on which Dr. Gish relied did not provide “clinically meaningful” evidence and were outdated, having been published in 1999 and 1975, respectively. Id. Instead, Dr. MacGinnitie cited a 2017 study which stated that measles vaccination prevents measles infection, thereby “prevent[ing] measles-associated short- and long-term immunomodulating effects.” Id. (citing Resp. Ex. C, Tab 3, Michael J. Mina, Measles, Immune Suppression and Vaccination: Direct and Indirect Nonspecific Vaccine Benefits, 74 J. Infection S10 (2017) (ECF No. 26-3)). The Mina study also posited generally that the MMR vaccine can protect against other diseases by stimulating the immune system. Id.; see also Resp. Ex. C, Tab 4, Measles, Committee on Infectious Disease, Red Book (2021) (ECF No. 26-4). Dr. MacGinnitie also noted the apparent contradiction of Dr. Gish’s theory that measles infections and potentially also measles vaccinations lead to autoimmune suppression. MacGinnitie Report at 8– 9; Hr’g Tr. at 162:15−20. Dr. MacGinnitie concluded that since AIH is an autoimmune condition—an overactivation of the immune system—any immunosuppression triggered by MMR 24 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 25 of 52 would likely be “protective against development of AIH.” MacGinnitie Report at 7−8; Hr’g Tr. at 162:15−20. Further, Dr. MacGinnitie contended that it was unlikely that the activation of Petitioner’s memory T cells from her prior vaccines would cause autoimmune disease. Hr’g Tr. at 189:25– 191:7. Similarly, Dr. MacGinnitie rejected Dr. Gish’s Th17 theory, taking issue with his interpretation of the Antunes study. Id. at 170:14–173:24; MacGinnitie Report at 9−10. Dr. MacGinnitie also asserted that Dr. Gish failed to provide any evidence that Th17 disease would cause AIH; rather, the studies he cites simply listed Th17 as “one of many potential pathways toward development of AIH” and as Th17 cells are “found in healthy humans,” his Th17 theory was not a sufficient explanation for development of autoimmunity. MacGinnitie Report at 9−10 (citing Resp. Ex. C, Tab 10, S.A. Khader et al., Th17 Cells at the Crossroads of Innate and Adaptive Immunity Against Infectious Diseases at the Mucosa, 2 Mucosal Immunology 403 (Sept. 2009) (ECF No. 26-10)).32 Dr. MacGinnitie also took issue with Dr. Gish’s position that the timing of the onset of Petitioner’s AIH supported her causal theory. Dr. MacGinnitie contends that Dr. Gish failed to support his assertion that symptom onset within one to five months of vaccination is generally acceptable to infer causation. MacGinnitie Report at 11; Hr’g Tr. at 173:25–174:25. Further, Dr. MacGinnitie asserted that onset of autoimmune diseases tends to occur weeks—not months—after infection or immunization. MacGinnitie Report at 11 (first citing Resp. Ex. C, Tab 16, Jonathon R. Carapetis, Acute Rheumatic Fever and Rheumatic Heart Disease, 2 Nature Reviews: Disease Primers (Jan. 2016) (ECF No. 26-16); and then citing Resp. Ex. C, Tab 17, Shaheen Sombans et 32 Dr. MacGinnitie also rejected Dr. Gish’s aluminum adjuvant theory, which Dr. Gish had “set[] aside” at the Entitlement Hearing. See supra note 20. 25 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 26 of 52 al., A Case Report of Acute Rheumatic Fever and a Brief Review of the Literature, Archives of Medical Science: Atherosclerotic Diseases (2018) (ECF No. 26-17)). Analogizing to a study he cited involving Guillain-Barré syndrome, Dr. MacGinnitie testified that he considers six weeks to be “the outer limit of what [he] would expect for a vaccine-triggered autoimmune injury.” Hr’g Tr. at 175:11−176:8 (discussing Resp. Ex. C, Tab 19, Thomas J. Safranek et al., Reassessment of the Association between Guillain-Barre Syndrome and Receipt of Swine Influenza Vaccine in 1976- 1977: Results of a Two-State Study, 133 Am. J. Epidemiology (1991) (ECF No. 26-19)). To that end, Dr. MacGinnitie pointed out that in the case reports Dr. Gish cited, the onset of AIH occurred within one month (and often sooner) of the relevant vaccination. Id. at 173:25–174:25 Dr. MacGinnitie also opined, that vaccines are generally only “a minor immune stimulus.” MacGinnitie Report at 10−11. He noted that vaccines are recommended for patients with AIH. Id. at 11. Such a recommendation, he contends, would be illogical if vaccines “were generally believed to play a role in triggering AIH.” Id. He also noted that none of Petitioner’s doctors—in particular the hepatologist who treated her AIH—associated her AIH with her MMR and Tdap vaccines. Id. at 12. III. The Decision On March 7, 2024, Chief Special Master Brian H. Corcoran held an Entitlement Hearing, in which Drs. Gish, Crippin, and MacGinnitie testified. See generally Hr’g Tr. On August 29, 2024, the Chief Special Master held that Petitioner was not entitled to compensation, because she had failed to “preponderantly establish [Althen] prongs one and two.” Exum, 2024 WL 4291116, at *13. With respect to prong one, the Chief Special Master held that Petitioner had not preponderantly established that the MMR and Tdap vaccines can cause AIH. Id. First, the Chief Special Master noted several issues with Dr. Gish’s theory, including that Dr. Gish had opined on 26 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 27 of 52 immunological matters, when his expertise was hepatology. Id. Specifically, the Chief Special Master reasoned that Dr. Gish’s theory relied on (1) “a false equivalence between the impact of the measles wild virus and vaccine,”33 (2) the “contradictory” idea that the same environmental trigger can cause both immune suppression and immune overactivation; (3) speculations about the Tdap vaccine, and (4) the “barely-plausible contention” that administering MMR and Tdap together increases risk of adverse effects. Id. Second, the Decision stated that Dr. Gish “could not imbue these contentions with reliability by drawing on immunologic expertise he lacks.” Id. Third, the Chief Special Master held that Dr. Gish failed to demonstrate “that the vaccines at issue could likely promote an autoimmune response resulting in AIH.” Id. He rejected Dr. Gish’s molecular mimicry theory because Dr. Gish failed to establish a homology between the relevant vaccine antigens and liver cells. Id. at *13−14. Fourth, the Chief Special Master also noted that case reports—on which Dr. Gish’s theory relied—generally are “known to be weak evidence of causation,” and only a few of the case reports cited by Dr. Gish involved a relevant vaccine. Id. at *14. With respect to Althen prong two, the Chief Special Master concluded that nothing other than the timing of Petitioner’s symptom onset and the type of symptoms she experienced supported the conclusion that Petitioner’s vaccines caused her AIH. Id. The Chief Special Master reasoned that this evidence is insufficient to demonstrate causation because the Federal Circuit has held that temporal proximity cannot establish causation between a vaccine and an injury. Id. (citing Grant v. Sec’y of Health & Hum. Servs., 956 F.2d 1144, 1148 (Fed. Cir. 1992)). The Chief Special Master further reasoned that the multiple alternative causes identified by Dr. Crippin, which were 33 Notably, Dr. Gish testified that a live vaccine infection is different from a wild-type infection because “the immune response [from a live vaccine infection] is initially less.” Hr’g Tr. at 36:19– 23. 27 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 28 of 52 acknowledged by—but not all “persuasively limit[ed] or exclude[d]” by—Dr. Gish, undermined Petitioner’s theory that the vaccines caused her AIH. Id. Put another way, the Chief Special Master held that there were “too many other possible explanations to find the vaccines were a substantial factor” for Petitioner to succeed on Althen prong two. Id. The Chief Special Master did not analyze the sufficiency of Petitioner’s evidence regarding prong three, because, under Federal Circuit precedent, “failure to establish even one of the three Althen prongs in the context of a causation-in-fact claim is sufficient basis for a claim’s dismissal.” Id. at *13 (citing Dobrydnev v. Sec’y of Health & Hum. Servs., 566 F. App’x 976, 980 (Fed. Cir. 2014)). IV. Petitioner’s Motion for Review On September 30, 2024, Petitioner filed her Motion for Review, urging this Court to set aside the Decision and grant entitlement, or, in the alternative, to remand this matter to the Chief Special Master “with direction on applying the proper legal standard.” Mot. at 24. Respondent filed its Response to Petitioner’s Motion for Review on October 30, 2024, and this Court conducted Oral Argument on December 19, 2024. See generally Resp.; OA Tr. STANDARD OF REVIEW Pursuant to 42 U.S.C. § 300aa-12(e)(2), when ruling on a Motion for Review, this Court may: “(A) uphold the findings of fact and conclusions of law of the special master and sustain the special master’s decision, (B) set aside any findings of fact or conclusion of law of the special master found to be arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law and issue its own findings of fact and conclusions of law, or (C) remand the petition to the special master for further action in accordance with the court’s direction.” 42 U.S.C. § 300aa- 12(e)(2). This Court reviews a special master’s factual determinations under the arbitrary and 28 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 29 of 52 capricious standard; legal questions under the “not in accordance with law” standard; and any discretionary rulings under the abuse of discretion standard. Munn v. Sec’y of Health and Hum. Servs., 970 F.2d 863, 870 n.10 (Fed. Cir. 1992). The scope of this Court’s review is deferential. Lampe v. Sec’y of Health & Hum. Servs., 219 F.3d 1357, 1360 (Fed. Cir. 2000). This Court must uphold factual findings of a special master so long as they are “based on evidence in the record that [is] not wholly implausible.” Cedillo v. Sec’y of Health & Hum. Servs., 617 F.3d 1328, 1338 (Fed. Cir. 2010) (quoting Lampe, 219 F.3d at 1363). Particularly in cases in which medical evidence of causation is in dispute, this Court will not “second guess” a special master’s factual determinations. Id. This Court also must “not reweigh the factual evidence, assess whether the special master correctly evaluated the evidence, or examine the probative value of the evidence or the credibility of the witnesses.” Porter v. Sec’y of Health & Hum. Servs., 663 F.3d 1242, 1249 (Fed. Cir. 2011). If a special master “‘has considered the relevant evidence of record, drawn plausible inferences and articulated a rational basis for the decision,’ then reversible error is ‘extremely difficult to demonstrate.’” Milik v. Sec’y of Health & Hum. Servs., 822 F.3d 1367, 1376 (Fed. Cir 2016) (quoting Hines v. Sec’y of Health & Hum. Servs., 940 F.2d 1518, 1528 (Fed. Cir. 1991)). A special master’s findings of fact also must be “supported by substantial evidence.” Doe v. Sec’y of Health & Hum. Servs., 601 F.3d 1349, 1355 (Fed. Cir. 2010) (citing Whitecotton v. Sec’y of Health & Hum. Servs., 81 F.3d 1099, 1105 (Fed. Cir. 1996), on remand from Shalala v. Whitecotton, 514 U.S. 268 (1995)). However, a “finder of fact generally is not required to itemize every piece of evidence on an issue and adopt or reject it.” Shapiro v. Sec’y of Health & Hum. Servs., 101 Fed. Cl. 532, 540 (2011) (citations omitted). Indeed, even when a special master makes 29 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 30 of 52 no express reference to certain evidence, the Court nonetheless must presume that he considered that evidence. Hazlehurst v. Sec’y of Health & Hum. Servs., 604 F.3d 1343, 1352 (Fed. Cir. 2010). Despite this, a special master must clearly articulate its reasons for its conclusions. See Hines, 940 F.2d at 1528; Stewart-Robinson v. Sec’y of Health & Hum. Servs., 173 Fed. Cl. 567, 576 (2024) (“[S]pecial masters are required to. . . . articulate a rational basis for their decisions.”); Doles v. Sec’y of Health & Hum. Servs., 163 Fed. Cl. 726 (2023), reconsideration denied, 163 Fed. Cl. 616, 731 (2023) (stating that special masters are “obligate[d]” to articulate the reasons for their decisions); Olson v. Sec’y of Health & Hum. Servs., 135 Fed. Cl. 670, 675 (2017), aff’d, 758 F. App’x 919 (Fed. Cir. 2018) (“When evaluating a motion for review, it is the Court’s task to determine whether the Special Master. . . .provided a reasoned explanation in his or her decision.”). A failure to do so may necessitate remand to the special master to clarify his or her rationale. M.R. v. United States, No. 16-1024V, 2023 WL 4930490 at *7 (Fed. Cl. Aug. 2, 2023) (finding “that the Chief Special Master’s Decision and record lack the clarity necessary for a thorough review of the Decision’s legal and factual bases” and remanding for further proceedings). DISCUSSION The Vaccine Act created the National Vaccine Injury Compensation Program to compensate parties presumed or proven to be injured by certain vaccines. 42 U.S.C. § 300aa–10 et seq. The Program was designed to “lessen the number of lawsuits against manufacturers and provide[] relative certainty and generosity of compensation awards in order to satisfy petitioners in a fair, expeditious, and generous manner.” Cloer v. Sec’y of Health & Hum. Servs., 654 F.3d 1322, 1326 (Fed. Cir. 2011) (en banc) (internal citations and quotation marks omitted) (alteration in original); see also K.G. v. Sec’y of Health & Hum. Servs., 951 F.3d 1374, 1380 (Fed. Cir. 2020) 30 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 31 of 52 (citing Cloer, 654 F.3d at 1325) (“The Vaccine Act is a pro-claimant regime meant to allow injured individuals a fair and fast path to compensation . . . .”). The Vaccine Act grants jurisdiction to the Office of Special Masters “over proceedings to determine if a petitioner . . . is entitled to compensation under the Program” for vaccine-related injuries or deaths and the amount of compensation owed. 42 U.S.C. § 300aa–12(a). Petitions alleging injuries are initially reviewed by a Special Master, who issues a decision on the petition. Bruesewitz v. Wyeth LLC, 562 U.S. 223, 228 (2011) (citing 42 U.S.C. §§ 300aa–11(a)(1), 12(d)(3)). Section 300aa–12(e) of the Vaccine Act grants the United States Court of Federal Claims authority to review decisions of the Special Master upon a party’s motion. 42 U.S.C. § 300aa– 12(e)(1); see Vaccine Rule 23. In reviewing a Special Master’s decision, this Court may set aside any findings of fact or conclusion of law . . . found to arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law and issue its own findings of fact and conclusions of law, or . . . remand the petition to the special master for further action in accordance with the court’s direction. 42 U.S.C. § 300aa-12(e)(2)(B)–(C); accord Vaccine Rule 27; see Munn, 970 F.2d at 867. Each standard of review referenced in the statute “applies to a different aspect of the judgment” and involves a different degree of deference given to the Special Master’s determinations. Munn, 970 F.2d at 870 n.10. “Fact findings are reviewed . . . under the arbitrary and capricious standard; legal questions under the ‘not in accordance with law’ standard; and discretionary rulings under the abuse of discretion standard.” Id.; accord Markovich v. Sec’y of Health & Hum. Servs., 477 F.3d 1353, 1356 (Fed. Cir. 2007). Petitioner may demonstrate eligibility for compensation in two ways: (1) by demonstrating that she received a vaccine listed on the Vaccine Injury Table, 42 U.S.C. § 300aa–14, and suffered an injury listed on that table within the statutorily prescribed time period; or (2) by demonstrating that the vaccine was the cause-in-fact of her condition where the injury is not on the Vaccine Injury 31 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 32 of 52 Table (an off-table injury). Milik, 822 F.3d at 1379; Capizzano v. Sec’y of Health & Hum. Servs., 440 F.3d 1317, 1319–20 (Fed. Cir. 2006) (citing Munn, 970 F.2d at 865); 42 U.S.C. §§ 300aa- 13(a)(1), 300aa-11(c)(1). The parties agree here that Petitioner’s claims concern alleged off-table injuries. See Resp. at 10; Petitioner’s Post-Hearing Brief (ECF No. 73) at 1–2. Regarding off- table injuries, Petitioner must prove by a preponderance of the evidence that her vaccinations were “not only a but-for cause of the injury but also a substantial factor in bringing about the injury.” Shyface v. Sec’y of Health & Hum. Servs., 165 F.3d 1344, 1352 (Fed. Cir. 1999); see also Pafford v. Sec’y of Health & Hum. Servs., 451 F.3d 1352, 1355 (2006) (petitioner must prove by preponderant evidence “both that her vaccinations were a substantial factor in causing the illness, disability, injury or condition and that the harm would not have occurred in the absence of the vaccination”). However, a petitioner need not prove that the vaccine was the “sole or predominant cause of her injury.” de Bazan v. Sec’y of Health & Hum. Servs., 539 F.3d 1347, 1351 (Fed. Cir. 2008) (citing Walther v. Sec’y of Health & Hum. Servs., 485 F.3d 1146, 1150 (Fed. Cir. 2007)). The Federal Circuit has distilled this actual causation inquiry into a three-part test. Althen v. Sec’y of Health & Hum. Servs., 418 F.3d 1274, 1278 (Fed. Cir. 2005). Petitioner must provide: (1) a medical theory causally connecting the vaccination and the injury; (2) a logical sequence of cause and effect showing that the vaccination was the reason for the injury; and (3) a showing of a proximate temporal relationship between vaccination and injury. Id.; see Boatmon v. Sec’y of Health & Hum. Servs., 941 F.3d 1351, 1354–55 (Fed. Cir. 2019) (quoting Moberly v. Sec’y of Health & Hum. Servs., 592 F.3d 1315, 1321–22 (Fed. Cir. 2010)). In this context, the preponderance standard “simply requires the trier of fact to believe that the existence of a fact is more probable than its nonexistence.” Moberly, 592 F.3d at 1322 n.2 (quoting Concrete Pipe & Prods. of Cal., Inc. v. Constr. Laborers Pension Tr. for S. Cal., 508 U.S. 602, 622 32 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 33 of 52 (1993)). A petitioner must prove each Althen prong by a preponderance of the evidence; failure to establish any one prong is dispositive. Boatmon, 941 F.3d at 1355; Oliver v. Sec’y of Health & Hum. Servs., 900 F.3d 1357, 1361 (Fed. Cir. 2018); Olson, 758 F. App’x at 922; Dobrydnev, 566 F. App’x at 980. At prong one, Petitioner must establish a “‘reputable medical or scientific explanation’ for [her] theory.” Boatmon, 941 F.3d at 1359 (quoting Moberly, 592 F.3d at 1322). The theory must be “sound and reliable,” though it “does not require medical or scientific certainty.” Id. (quoting Knudsen v. Sec’y of Health & Hum. Servs., 35 F.3d 543, 548–49 (Fed. Cir. 1994)). At prong two, Petitioner must demonstrate that “the vaccine caused [her] injury.” Capizzano, 440 F.3d at 1326 (citing 42 U.S.C. §§ 300aa–11(c)(1)–13(a)(1)). At prong three, Petitioner must demonstrate a temporal relationship between the vaccination and her injury. See Pafford, 451 F.3d at 1358; see also id. (citing Capizzano, 440 F.3d at 1326) (“Evidence demonstrating petitioner’s injury occurred within a medically acceptable time frame bolsters a link between the injury alleged and the vaccination at issue under the ‘but-for’ prong of the causation analysis.”). Evidence used to satisfy one prong may be used to satisfy the requirements of another Althen prong. Capizzano, 440 F.3d at 1326. “Once a petitioner establishes a prima facie case, the government then bears the burden of establishing alternative causation by a preponderance of the evidence.” Cedillo, 617 F.3d at 1335 (citing Walther, 485 F.3d at 1151). After such a burden shift, the respondent must demonstrate by a preponderance of the evidence that the injury described in the petition was caused by factors unrelated to the administration of the vaccine described in the petition. 42 U.S.C. § 300aa– 13(a)(1)(B); Althen, 418 F.3d at 1278 (internal citation omitted). However, if Petitioner fails to establish a prima facie case, the burden does not shift to Respondent. See Doe, 601 F.3d at 1358. 33 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 34 of 52 Regardless of whether the burden shifts, the special master may consider evidence of alternative causation presented by the respondent in determining whether the petitioner has established a prima facie case, as the special master is to consider the record as a whole in determining causation where multiple possible sources of injury may exist. Stone v. Sec’y of Health & Hum. Servs., 676 F.3d 1373, 1379 (Fed. Cir. 2012) (“Our decisions support the commonsense proposition that evidence of other possible sources of injury can be relevant not only to the ‘factors unrelated’ defense, but also to whether a prima facie showing has been made that the vaccine was a substantial factor in causing the injury in question.”). “[S]pecial masters have broad discretion to weigh evidence and make factual determinations.” Dougherty v. Sec’y of Health & Hum. Servs., 141 Fed. Cl. 223, 229 (2018). In adjudicating a Petition, the Court of Federal Claims does “not reweigh the factual evidence, assess whether the special master correctly evaluated the evidence, or examine the probative value of the evidence or the credibility of the witnesses—these are all matters within the purview of the fact finder.” Porter, 663 F.3d at 1249; see also Kalajdzic v. Sec’y of Health & Hum. Servs., No. 17- 792V, at 12 (Fed. Cl. Oct. 27, 2022) (ECF No. 79) (internal citations omitted), aff’d, No. 2023- 1321, 2024 WL 3064398 (Fed. Cir. June 20, 2024). Additionally, this Court should refrain from “‘second guess[ing] the Special Master[’]s fact-intensive conclusions’ particularly in cases ‘in which the medical evidence of causation is in dispute.’” Cedillo, 617 F.3d at 1338 (second alteration in original) (quoting Hodges v. Sec’y of Health & Hum. Servs., 9 F.3d 958, 961 (Fed. Cir. 1993)). “[R]eversible error is extremely difficult to demonstrate if the special master has considered the relevant evidence of record, drawn plausible inferences and articulated a rational basis for the decision.” Kirby v. Sec’y of Health & Hum. Servs., 997 F.3d 1378, 1381 (Fed. Cir. 2021) (alteration in original) (quoting Lampe, 219 F.3d at 1360). 34 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 35 of 52 In weighing the evidence, the special master has discretion to determine the relative weight of the evidence, including medical records. Burns v. Sec’y of Health & Hum. Servs., 3 F.3d 415, 417 (Fed. Cir. 1993); see Hibbard v. Sec’y of Health & Hum. Servs., 698 F.3d 1355, 1368 (Fed. Cir. 2012). A special master is “not required to discuss every piece of evidence or testimony in [his or] her decision,” as the special master is presumed to have considered the whole record. Snyder v. Sec’y of Health & Hum. Servs., 88 Fed. Cl. 706, 728 (2009) (citing Maza v. Sec’y of Health & Hum. Servs., 67 Fed. Cl. 36, 38 (2005)); see Moriarty v. Sec’y of Health & Hum. Servs., 844 F.3d 1322, 1328 (Fed. Cir. 2016) (internal citations omitted) (“We generally presume that a special master considered the relevant record evidence even though he does not explicitly reference such evidence in his decision. However, this presumption does not apply, as in this case, where a special master indicates otherwise.”). The purpose of the Vaccine Act’s standard of proof is “to allow the finding of causation in a field bereft of complete and direct proof of how vaccines affect the human body,” even if the alleged link is “hitherto unproven in medicine.” Althen, 418 F.3d at 1280. Therefore, “close calls regarding causation are resolved in favor of injured claimants.” Id. (citing Knudsen, 35 F.3d at 549). In the present action, Petitioner alleges an off-table injury; therefore, she must prove by a preponderance of the evidence that the MMR and Tdap vaccines caused her AIH. Capizzano, 440 F.3d at 1319−20; see also 42 U.S.C. §§ 300aa-13(a)(1), 11(c)(1)(C)(ii)(I). Petitioner contends that the Chief Special Master erred in his Decision by (i) articulating and applying an erroneous legal standard for Althen prong one, (ii) reaching conclusions on Althen prong two that were contrary to 35 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 36 of 52 law, and (iii) failing to analyze Althen prong three. In sum, Petitioner argues that the Chief Special Master committed reversible legal error with respect to each Althen prong. As described more fully below, the Decision’s analysis lacks the clarity, specificity, and clear rationales for its conclusions that are necessary to determine whether the Chief Special Master committed legal error. Accordingly, pursuant to 42 U.S.C. § 300aa-12(e)(2)(C), the Court remands this action to the Chief Special Master to more thoroughly state the rationale for his rulings regarding Althen prongs one and two in accordance with applicable legal standards. After remand, it may be that the Chief Special Master either changes his ultimate conclusions or not; in either instance, any decision issued on remand must clearly and thoroughly state the rationale for each ruling with citation to the evidentiary and legal bases for each ruling, along with a clear statement of the legal standard being applied. I. Althen Prong One While the Decision articulated the correct legal standard for Althen prong one, it failed to articulate adequate rationale for the conclusions it reached. Accordingly, for the reasons stated below, the Court remands this action to the Chief Special Master to clearly articulate his Althen prong one analysis, stating any rationale for his conclusions and providing citations to record evidence. A. The Decision Articulated the Correct Legal Standard for Althen Prong One. At Althen prong one, a petitioner must demonstrate that the relevant vaccine can cause Petitioner’s alleged injury. Pafford, 451 F.3d at 1355–56. Accordingly, to satisfy Althen prong one, a petitioner must provide “a medical theory causally connecting the vaccination and the injury.” Althen, 418 F.3d at 1278. This means that “a petitioner must provide a reputable medical or scientific explanation that pertains specifically to the petitioner’s case, although the explanation need only be ‘legally probable, not medically or scientifically certain.’” See Trollinger v. Sec’y of 36 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 37 of 52 Health & Hum. Servs., 167 Fed. Cl. 127, 136 (2023) (quoting Broekelschen v. Sec’y of Health & Hum. Servs., 618 F.3d 1339, 1345 (Fed. Cir. 2010)). As noted, the Petitioner must satisfy Althen prong one by a preponderance of evidence. Boatmon, 941 F.3d at 1355. In evaluating whether a special master failed to recognize a proposed theory, the Court reviews whether Petitioner offered reliable evidence on the record to support the theory. See Broekelschen, 618 F.3d at 1350–51 (affirming a finding of failure at prong one where the evidence relied upon (literature review) was weak and there was little evidence in the record regarding whether the influenza vaccine could cause the asserted injury). Petitioner argues that the Chief Special Master erred by “conflat[ing] the burden of proof linking a petitioner’s vaccine to injury – preponderant evidence – from the standard of certainty required of petitioner’s medical theory – plausibility.” Mot. at 7 (citing LaLonde v. Sec’y of Health & Hum. Servs., 746 F.3d 1334, 1340 (Fed. Cir. 2014)). The parties agree, as they must, that Petitioner must prove Althen prong one by a preponderance of the evidence. Mot. at 8; Resp. at 12−13; see also 42 U.S.C. § 300aa-13(a). The crux of their dispute is what Petitioner had to demonstrate − and how she could make that showing − to meet this burden. Mot. at 7−8; Resp. at 12. Petitioner posits that “preponderantly proving a biologically plausible scientific explanation connecting the vaccinations and the injury can establish” Althen’s first prong. Mot. at 11.34 34 Petitioner takes issue with the Decision’s discussion of plausibility. Mot. at 6−8. While the Decision’s statement that “the Federal Circuit has consistently rejected the contention that [Althen prong one] can be satisfied merely by establishing the proposed causal theory’s scientific or medical plausibility,” may be a slight overstatement, it is of no moment because the Decision clearly stated the proper legal standard for Althen prong one. Exum, 2024 WL 4291116, at *9 (citing Kalajdzic, 2024 WL 3064398, at *2); Bechel, 168 Fed. Cl. 602, 617−19 (2023). Indeed, the Decision even acknowledged that “[p]lausibility . . . in many cases may be enough to satisfy Althen prong one.” Exum, 2024 WL 4291116, at *9 (citing Contreras v. Sec’y of Health & Hum. Servs., 121 Fed. Cl. 230, 245 (2015), vacated on other grounds, 844 F.3d 1363 (Fed. Cir. 2017)). 37 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 38 of 52 Respondent contends that Petitioner must prove a reputable, sound, reliable, and persuasive theory. Resp. at 12, 19−20. Federal Circuit precedent establishes that a petitioner must provide a reputable medical theory based on a sound and reliable medical or scientific explanation to satisfy Althen prong one. Boatmon, 941 F.3d at 1359 (first quoting Grant, 956 F.2d at 1148; and then quoting Knudsen, 35 F.3d at 548−49); Kirby, 997 F.3d at 1384−85. The Decision correctly articulated that standard here. Indeed, the Federal Circuit recently affirmed a different decision of the Chief Special Master in which he articulated the standard in nearly the same way. See Kalajdzic, 2024 WL 3064398, at *2. Here, the Decision held that Petitioner had not “preponderantly established that it is likely that the MMR and Tdap vaccines—alone or in combination—can cause AIH.” Exum, 2024 WL 4291116, at *13. It explained that petitioners must provide a “reputable medical theory” based on a “sound and reliable medical or scientific explanation,” and noted that the theory need only be “legally probable, not medically or scientifically certain.” Id. at *9 (first quoting Pafford, 451 F.3d at 1355−56; and then quoting Knudsen, 35 F.3d at 548−49). These are correct statements of Federal Circuit precedent. Boatmon, 941 F.3d at 1359 (first quoting Grant, 956 F.2d at 1148; and then quoting Knudsen, 35 F.3d at 548−49); Kirby, 997 F.3d at 1384−85. Indeed, Vaccine Act petitioners must set forth some indicia of reliability to support their prong one theory. Boatmon, 941 F.3d at 1359−60. The standards the Chief Special Master articulated here plainly comport with that principle. Thus, the Decision articulated the proper standard at Althen prong one. B. The Decision Did Not Sufficiently Articulate the Legal, Factual, and Evidentiary Rationales for its Althen Prong One Conclusion. Although the Decision correctly articulated the legal standard for Althen prong one, Petitioner asserts that the Chief Special Master erred by incorrectly applying that standard. 38 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 39 of 52 Specifically, Petitioner contends that (1) the Chief Special Master’s application of the “sound and reliable” standard was legal error, and that he impermissibly required her to prove a persuasive theory; (2) the Chief Special Master erred by requiring her to “provide specific biological mechanisms”; and (3) the Chief Special Master improperly “disguise[d] the application of an improper burden” in terms of evidentiary persuasiveness and as a credibility determination. Mot. at 8−9, 13−14. Each of Petitioner’s arguments is an extension of the same contention—that the Chief Special Master held Petitioner’s Althen prong one theory to too high an evidentiary standard. The Court concludes that the Chief Special Master insufficiently articulated in the Decision his legal, factual, and evidentiary rationales for his conclusions related to Althen prong one, and accordingly, the action must be remanded. The Chief Special Master’s prong one analysis involved two steps. First, he identified numerous weaknesses in the logical underpinnings of Dr. Gish’s theories, made factual findings based on those identified weaknesses, and concluded that Dr. Gish’s testimony alone could not “imbue” any of the missing pieces with credibility, as he is not an immunologist. Exum, 2024 WL 4291116, at *13−14. Second, the Chief Special Master found Petitioner’s case report evidence to be only minimally probative, due to the stated weakness of case reports as evidence generally and because only a few of the case reports in the record “involved a relevant vaccine.” Id. at *14. As explained further below, because the Chief Special Master’s analysis did not adequately engage with the medical literature and appeared to reject the case report evidence out of hand, it is unclear whether the Chief Special Master properly applied the proper legal standard—i.e., evaluated the medical literature “not through the lens of the laboratorian, but instead from the vantage point of the Vaccine Act’s preponderant evidence standard.” Andreu v. Sec’y of Health & Hum. Servs., 569 F.3d 1367, 1380 (Fed. Cir. 2009). 39 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 40 of 52 The Chief Special Master’s analysis did not directly engage with specific items of medical literature filed in this case, other than one passing reference to Saliba & Elias.35 See Exum, 2024 WL 4291116, at *13−15. For example, the Chief Special Master first found that “[Dr. Gish’s] points about the immune-suppressive character of the MMR vaccine . . . relied on a false equivalence between the impact of the measles wild virus and vaccine.” Id. at *13. However, his analysis does not provide a rationale for rejecting the Nanan and Munyer articles (two items of literature Dr. Gish cited in support of this theory); the Decision’s analysis merely asserts its conclusion on the basis that “this kind of argument has been rejected in the Program before.”36 Id. at n.6. While it is not legal error for a special master to review medical literature and conclude that it does not support a petitioner’s theory, the special master should “provide[] logical reasoning for finding certain articles unreliable.” K.L. v. Sec’y of Health & Hum. Servs., 134 Fed. Cl. 579, 607 (2017) (citing Cedillo, 617 F.3d at 1345–46) (“The Federal Circuit has found that it is not error for a Special Master to consider the medical literature offered by an expert witness . . . and after review find it does not support the petitioner’s theory of causation, so long as the Special Master 35 Rather, the Decision describes the medical literature only in the context of summarizing of the hearing witnesses’ testimony. See Exum, 2024 WL 4291116 at *3−8. 36 The Decision references this literature, but only in the portion of the Decision summarizing hearing witnesses’ testimony. Exum, 2024 WL 4291116 at *4, *7. Specifically, that summary describes how the Nanan and Munyer articles supported Dr. Gish’s theory. Id. at *4. The Decision also references Dr. MacGinnitie’s testimony that the Nanan and Munyer articles were “lacking in clinical value or [] outdated,” and cites the more recent medical literature Dr. MacGinnitie cited supporting that the distinction between the wild-type and vaccine measles infections is a meaningful one. Id. at *7. However, the Decision’s analysis section lacks any discussion of the rationale for crediting Dr. MacGinnitie’s testimony over Dr. Gish’s based on the merits of the relevant literature (including the Nanan, Munyer, and Mina articles, and the excerpt of the Red Book). To the extent the Chief Special Master is adopting Dr. MacGinnitie’s rebuttal of the Nanan and Munyer articles as his own, he should make that clear in his decision, and articulate his rationale for doing so. 40 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 41 of 52 provides logical reasoning for finding certain articles unreliable.”). Given the lack of any real discussion in the Decision regarding which items of medical literature the Chief Special Master found more persuasive and why, the legal standard he applied to come to his conclusion is unclear.37 Indeed, while the Decision concluded that Dr. Gish “made assumptions about the impact of the Tdap vaccine . . . that rely more on supposition than independent evidence,” the Decision’s analysis did not address, for example, the Antunes article cited in support of Dr. Gish’s contentions about the Tdap vaccine.38 Further, while the Chief Special Master’s conclusions were largely consistent with Dr. MacGinnitie’s testimony, the extent to which the Chief Special Master credited Dr. MacGinnitie’s testimony or why he did so was not clear on the face of the Decision.39 See Exum, 2024 WL 4291116, at *13−14. Not only was the Decision’s analysis ambiguous as to whether it was wholly crediting Dr. MacGinnitie’s testimony, insofar as the Chief Special Master 37 Additionally, in her Motion, Petitioner cites two items of medical literature that the Decision does not directly address—Rennick and McMahon. The Court recognizes that a special master need not address every piece of medical literature a petitioner files or references. Hazlehurst, 604 F.3d at 1352. However, under these particular facts, failure to mention apparently relevant studies adds to the lack of clarity regarding the standard under which the Chief Special Master evaluated the evidence before him. 38 Like the Nanan and Munyer articles, the Decision references the Antunes article only in its discussion of the Hearing Witnesses’ testimony, and the Chief Special Master’s finding is consistent with Dr. MacGinnitie’s testimony criticizing the article and doubting its relevance to Petitioner. Exum, 2024 WL 4291116, at *7. To the extent that the Chief Special Master intends to adopt Dr. MacGinnitie’s position regarding this aspect of Dr. Gish’s theory on remand, the Decision must make that clear and provide a rational basis for doing so. 39 Specifically, the Decision only directly credits Dr. MacGinnitie’s testimony with respect to two of the Chief Special Master’s factual findings. Exum, 2024 WL 4291116, at *13 (“In fact, as Dr. MacGinnitie noted, the measles vaccine’s impact is to make immune suppression less likely—and there is a contradictory quality to arguing that immune suppression would cause a disease reaction that occurs due to an uncontrolled immune response.”) (emphasis added); id. at *14 (“Dr. Gish has not made this showing [of a specific homology]—which, as Dr. MacGinnitie noted, is by itself not necessarily sufficient evidence to conclude an autoimmune process linked to vaccination has been established.”) (emphasis added). 41 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 42 of 52 was doing so, the Decision’s analysis section failed to sufficiently engage with the evidence in the record to explain why. The Chief Special Master’s rejection of case report evidence adds to the lack of clarity regarding the legal standard he applied. It is well-established that a special master cannot “requir[e] conclusive evidence in the medical literature” connecting the relevant vaccine and the relevant injury. Andreu, 569 F.3d at 1378. While case reports “do not purport to establish causation definitively, and this deficiency does indeed reduce their evidentiary value . . . the fact that case reports can by their nature only present indicia of causation does not deprive them of all evidentiary weight.” Echols v. Sec’y of Health & Hum. Servs., 165 Fed. Cl. 9, 17–18 (2023) (quoting Paluck v. Sec’y of Health & Hum. Servs., 104 Fed. Cl. 457, 475 (2012), aff’d, 786 F.3d 1373 (Fed. Cir. 2015)). The Decision correctly noted only a few of the case reports cited by Petitioner involved a relevant vaccine. Exum, 2024 WL 4291116, at *14. However, other than brushing them aside as generally weak evidence of causation, the Decision’s analysis did not address the few case reports that do involve a relevant vaccine. Id. at *13–14. Indeed, the Decision could be interpreted as rejecting the case reports cited by Petitioner out of hand. See id. at *13 (finding that Dr. Gish’s contention “that both vaccines administered at the same time raise the risk of an aberrant response” was “barely-plausible” and “lack[ing] corroboration” in the record, notwithstanding filed case reports describing patients who developed AIH after receiving multiple vaccines concomitantly). Particularly considering Petitioner’s argument that these case reports are relevant because they involve either relevant vaccine antigens or patients who received multiple vaccinations concomitantly, the Chief Special Master must explain his rationale fully to the extent he continues 42 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 43 of 52 to find these case reports unpersuasive or distinguishable after reevaluation on remand.40 See Mot. at 10, 21; Exum, 2024 WL 4291116, at *6−8. Accordingly, the Court concludes that these aspects of the Chief Special Master’s analysis warrant remand as “the Althen prong one standard required him to evaluate the overall reputability, soundness, and reliability of the posited medical or scientific theory,” and it is unclear on the face of the Decision how the Chief Special Master applied that legal standard here.41 Bechel, 168 Fed. Cl. at 620. The Court recognizes that the Chief Special Master need not address every piece of medical literature a petitioner files or references, and “has discretion to determine the relative weight to give to evidence in the record, provided he or she offers a rational basis.” K.L., 134 Fed. Cl. at 608 (emphasis added) (citing Andreu, 569 F.3d at 1379); Hazlehurst, 604 F.3d at 1352. The Court further does not intend to second-guess credibility determinations where the Decision articulates a rational basis for such determinations. See K.L., 134 Fed. Cl. at 608. However, the Chief Special Master must provide a rationale for crediting or discrediting the medical literature filed in this case; such a rationale supporting any conclusions here is necessary to confirm that the 40 The Court does not make any finding as to the strength of the case report evidence, particularly because the Court does “not reweigh the factual evidence, assess whether the special master correctly evaluated the evidence, or examine the probative value of the evidence or the credibility of the witnesses.” Porter, 663 F.3d at 1249; Echols, 165 Fed. Cl. at 18; but see Patton v. Sec’y of Health & Hum. Servs., 157 Fed. Cl. 159, 169 (2021) (concluding that a theory was sound and reliable where it was supported by “the expert opinion of an experienced neurologist, four case reports, three medical articles, and the diagnoses of four treating physicians”). Rather, the Court finds that it is necessary for the Chief Special Master to discuss the merits of the medical literature, or lack thereof, to ensure application of the proper legal standard. 41 While the Decision acknowledges that “[p]etitioners may satisfy the first Althen prong without resort to medical literature, epidemiological studies, demonstration of a specific mechanism, or a generally accepted medical theory,” and states that the Chief Special Master “reviewed all of the medical literature submitted,” those statements do not resolve any lack of clarity with respect to how he evaluated the medical literature filed in this case, and any reasons for crediting certain articles over others. Exum, 2024 WL 4291116, at *9 (citing Andreu, 569 F.3d at 1378−79), *12. 43 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 44 of 52 prong one legal standard was correctly applied. In sum, the Decision did not sufficiently articulate the legal, factual, and evidentiary bases of its conclusion that Petitioner failed to carry her prong one burden. See id. at 607 (citing Cedillo, 617 F.2d at 1345−46). Under these circumstances, remand is appropriate to ensure that the Chief Special Master does not require more of Petitioner’s theory than the Althen prong one standard requires. Indeed, as “close calls regarding causation are resolved in favor of injured claimants,” the Court agrees with Petitioner that, on this particular record, remand is appropriate. Althen, 418 F.3d at 1280; see Mot. at 5. Specifically, on remand, the Chief Special Master should provide a more fulsome explanation to the extent he makes conclusions regarding (1) the probative weight of the medical literature Petitioner cited, including Petitioner’s case reports involving relevant vaccines and vaccine antigens, (2) his rationale for accepting or rejecting that evidence; and, as necessary, (3) the extent to which he is crediting each expert’s testimony; and (4) his rationale for doing so. Moberly, 592 F.3d at 1326 (“What Andreu prohibited was for the finder of fact to reject evidence based on an unduly stringent legal test while characterizing the rejection as based on the reliability of particular evidence or the credibility of a particular witness.”). In other words, the Chief Special Master must support any analysis of conclusions on remand to provide a more fulsome discussion of the “quantity and quality” of the medical literature presented. See, e.g., Howard v. Sec’y of Health & Hum. Servs., No.16-1592V, 2023 WL 4117370, at *6 (Fed. Cl. May 18, 2023) aff’d, No. 2023-1816, 2024 WL 2873301 (Fed. Cir. June 7, 2024) (per curiam) (affirming the Chief Special Master’s application of prong one where “[t]he Decision grappled with the quality and quantity of the evidence—not its circumstantiality—and found both metrics lacking”); Bechel, 168 Fed. Cl. at 622 (“Given the extensive and well-reasoned analysis provided by the Chief Special Master, the Court rejects Petitioners’ argument that he improperly discounted evidence because it was 44 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 45 of 52 circumstantial rather than direct and improperly heightened the legal standard of the first Althen prong.”). II. Althen Prong Two Under Althen prong two, Petitioner must prove actual causation by a preponderance of the evidence. Boatmon, 941 F.3d at 1355. Specifically, to prevail on prong two, a petitioner must prove “a logical sequence of cause and effect showing that the vaccination was the reason for the injury” by a preponderance of the evidence. Oliver, 900 F.3d at 1361 (quoting Althen, 418 F.3d at 1278). This “means what it sounds like” – a petitioner’s “theory of cause and effect must be logical.” Capizzano, 440 F.3d at 1326. A showing of a proximate temporal relationship between vaccination and injury, or a “simplistic elimination of other potential causes of the injury” is insufficient to prove actual causation. Althen, 418 F.3d at 1278; see also Moberly, 592 F.3d at 1323 (quoting Althen, 418 F.3d at 1278). Despite this, the law is clear that “a special master may not require the petitioner to shoulder the burden of eliminating all possible alternative causes in order establish a prima facie case.” Stone, 676 F.3d at 1380.42 However, “when petitioners attempt to eliminate other possible causes to buttress their theory of causation, the special master should evaluate such evidence in determining whether a prima facie case has been established.” Doe, 601 F.3d at 1358. Here, with respect to Althen prong two, the Chief Special Master concluded that the record does not support the assertion that Petitioner’s Tdap and MMR vaccinations caused her AIH for two reasons. Exum, 2024 WL 4291116, at *14. First, the Decision noted that “[n]othing in the medical record (beyond the symptoms Petitioner began to experience post-vaccination) tends to 42 The petitioner may, instead, “rule out possible alternative causes to prove causation-in-fact when evidence as to the Althen requirements is insufficient.” de Bazan, 539 F.3d at 1352 n.3 (citing Walther, 485 F.3d at 1149–50). 45 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 46 of 52 support the conclusion that the vaccines caused her AIH,” and declined to “elevate” the temporal proximity of the vaccine and injury into evidence of causation. Id. (citing Grant, 956 F.2d at 1148). In so holding, the Chief Special Master declined to give weight to Petitioner’s post-vaccination symptoms and the fact that she exhibited no evidence of liver disease or hepatitis pre-vaccination. Id. n.7. Second, the Chief Special Master considered the evidence of alternative causes of Petitioner’s AIH, including her post-vaccination foreign travel, anti-malarial medication, supplements, her IUD, and her Epstein-Barr infection. Id. at *5, *13–14. The Chief Special Master concluded that each of these causes were “reasonably-likely”; and therefore, (i) “there are too many other possible explanations to find the vaccines were a substantial factor as well,” and (ii) “collectively [the other possible explanations] further undermine Petitioner’s showing.” Id. at *14. Petitioner contends that the Decision’s conclusions concerning prong two are contrary to law because (1) she preponderantly proved a logical sequence of cause and effect, (2) Respondent did not meet its purported burden to prove “that an alternative causal factor was principally responsible for causing [her] AIH illness,” and (3) the Chief Special Master’s consideration of alternative causes was improper. Mot. at 16−18. First, Petitioner argues that the Decision’s conclusion that Petitioner failed to satisfy Althen prong two is contrary to law as Petitioner has preponderantly proven a logical sequence of cause and effect. Mot. at 17. Petitioner challenges the Chief Special Master’s conclusion that “[n]othing in the medical record (beyond the symptoms Petitioner began to experience post-vaccination) tends to support the conclusion that the vaccines caused her AIH” as legal error. Exum, 2024 WL 4291116, at *14; Mot. at 16. Specifically, she asserts that in addition to the mere temporal association between the vaccines and her AIH, (1) Dr. Gish’s testimony, (2) the medical literature, 46 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 47 of 52 and (3) Petitioner’s medical records, each support her logical sequence of cause and effect. Mot. at 16−24. The Decision reflects that the Chief Special Master considered Petitioner’s evidence and found that it was not specific or persuasive enough to have probative weight at prong two. The Decision acknowledges Dr. Gish’s testimony that “the timing of symptoms, the timing of laboratory tests, the liver biopsy, all fits a classic triggering event and onset of autoimmune disease.” Id. at *4. The Chief Special Master’s reference to this testimony, taken together with his ultimate conclusion that “[n]othing in the medical record (beyond the symptoms Petitioner began to experience post-vaccination) tends to support that the vaccines caused her AIH” indicates that he considered Dr. Gish’s testimony but did not find it sufficiently probative of a logical sequence of cause and effect. Id. at *14. The Court declines to “reweigh the factual evidence, assess whether the special master correctly evaluated the evidence, or examine the probative value of the evidence or the credibility of the witnesses.” Porter, 663 F.3d at 1249. However, Petitioner also emphasizes that her prong one theory supports her logical sequence of cause and effect at prong two; specifically, she points to the “relevance of the case report evidence supporting [her] factual circumstances,” noting similarities in her case and the case reports, such as “receiving multiple vaccine antigens,” including the antigens included in the Tdap and MMR vaccines, and that some studies were relevant to Petitioner given her “personal hepatitis A vaccine history.” Mot. at 19−21. Thus, to the extent that, on remand, the Chief Special Master’s analysis of prong one affects his findings pertaining to Petitioner’s prong two logical sequence of cause and effect, the Chief Special Master should revise and explain those findings accordingly.43 43 The Court does not suggest or direct that, on remand, the Chief Special Master’s analysis should or necessarily will result in a different outcome; rather, the Court reaches its decision based on the 47 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 48 of 52 Second, Petitioner contends that the Chief Special Master committed legal error because “[i]t cannot be preponderantly concluded that an alternative causal factor was principally responsible for causing [Petitioner’s] AIH illness.” Mot. at 17−18 (citing Knudsen, 35 F.3d at 549); OA Tr. 71:17−72:5. Under 42 U.S.C. § 300aa–13(a)(1)(B), compensation may only be awarded to a petitioner if, on the record as a whole, “there is not a preponderance of the evidence that the illness, disability, injury, condition, or death described in the petition is due to factors unrelated to the administration of the vaccine described in the petition.” 42 U.S.C. § 300aa– 13(a)(1)(B) (noting that “[t]he special master or court may not make such a finding based on claims of a petitioner alone, unsubstantiated by medical records or by medical opinion”). The respondent carries the burden to prove that a “factor[] unrelated” to the vaccine was the sole cause of a petitioner’s injury. Doe, 601 F.3d at 1357. However, the burden only shifts to the respondent if the special master concludes that petitioner has proven her prima facie case. Id. at 1357−58 (first citing Doe/11 v. Sec’y of Health & Hum. Servs., 87 Fed. Cl. 1, 12 (2009); then citing Pafford, 451 F.3d at 1357–59; and then citing Shyface, 165 F.3d 1344). Thus, the Chief Special Master correctly did not shift the burden to Respondent here, because he concluded that Petitioner had failed to meet Althen prong one, and a petitioner must prove all three prongs of Althen to prove her prima facie case. Oliver, 900 F.3d at 1361. Third, Petitioner argues that the Chief Special Master’s consideration of evidence of potential alternative causes for her ailment was legal error because he “applied an erroneous ‘reasonable theory’ legal standard to conclude that [Petitioner] ‘did not persuasively limit or exclude all’ other possibilities.” Mot. at 16−18 (quoting Exum, 2024 WL 4291116, at *14). need for additional reasoning to confirm application of the correct legal standard, which could result in a different outcome. 48 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 49 of 52 Petitioner contends that the Chief Special Master cannot “deviate from the correct ‘reputable,’ ‘sound and reliable,’ standard and articulate a lower ‘reasonably-likely’ standard for alternate causation, to then erroneously conclude that [Petitioner] could not prove a prima facie case.” Id. at 18. As noted, the Chief Special Master can consider evidence of alternative causes in his evaluation of Petitioner’s prima facie case. Doe, 601 F.3d at 1358. However, the manner in the Decision considered this evidence gives the Court pause. Specifically, the Decision states, “[w]hile Dr. Gish did observe the absence of many risk factors for AIH relevant to Petitioner, he did not persuasively limit or exclude all of them.” Exum, 2024 WL 4291116, at *14 (emphasis added). In reaching this conclusion, the Chief Special Master also emphasized the importance of these possible alternative causes. Id. (“More important are the circumstances in which Petitioner received these vaccines.”) (emphasis added). While the Federal Circuit has held that a “petitioner as a practical matter may be required to eliminate potential alternative causes where the petitioner’s other evidence on causation is insufficient,” and that the government may present evidence of alternative causes, the law is clear that “a special master may not require the petitioner to shoulder the burden of eliminating all possible alternative causes in order establish a prima facie case.” Walther, 485 F.3d at 1149−50 (citing Pafford, 451 F.3d at 1359); Stone, 676 F.3d at 1380; see Doe, 601 F.3d at 1358. Although the Decision elsewhere acknowledges that “claimants are never obligated to rule out alternative causes as part of their initial burden,” its problematic framing of the alternative causation discussion can lead to a reasonable conclusion that the Chief Special Master may have violated that axiom. Exum, 2024 WL 4291116, at *14 (citing Stone, 676 F.3d at 1380). Particularly, as noted, the Decision emphasized this aspect of the analysis—describing the failure to rule out alternative causes as “[m]ore important” than the weakness in Petitioner’s other 49 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 50 of 52 prong two arguments—and specifically noted that Petitioner did not “persuasively limit or exclude all of” the possible alternative causes. Id. (emphasis added). The Federal Circuit has recognized that there is a “fine line between a court properly considering evidence in the record, and improperly placing the burden on the petitioner to prove that her [injury] was not caused by [an alternative cause],” and the Court finds that, the Decision, as worded, may fall on the wrong side of that line. Sharpe v. Sec’y of Health & Hum. Servs., 964 F.3d 1072, 1082 (Fed. Cir. 2020) (internal citation omitted). However, due to the lack of elaboration and conflict between the recitation of the legal standard in the analysis section of the Decision (which correctly noted that “claimants are never obligated to rule out alternative causes as a part of their initial burden”) and the analysis itself, it is unclear whether that line was definitively crossed. Exum, 2024 WL 4291116, at *14. Indeed, the Decision could potentially be read as proper, given its determination that the other evidence supporting Petitioner’s claim was insufficient—which Doe, Walther, and Pafford permit—but also could be understood as requiring Petitioner to “shoulder the burden of eliminating all possible alternative causes,” which Doe, Walther, and Stone forbid. The noted lack of clarity regarding prong one, that the Chief Special Master’s prong one analysis influenced his conclusion on prong two, and the Decision’s above-noted reference to Petitioner’s failure to rule out alternate causes, supports Petitioner’s request for remand. See id. (“In this context, there are too many other possible explanations to find the vaccines were a substantial factor as well (especially given the thin showing overall on the “can cause” prong)—and collectively they further undermine Petitioner's showing.”). On remand, the Chief Special Master must (1) revise his findings on prong two, only to the extent that his prong one analysis on remand affects those findings, (2) revise his analysis pertaining to alternative causes, insofar as he improperly required Petitioner to “persuasively limit 50 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 51 of 52 or exclude all of them,” and, importantly, (3) fully describe his rationale for all of his prong two conclusions in the remand decision. III. Althen Prong Three Petitioner argues that the Chief Special Master’s failure to analyze Althen prong three constituted legal error. Mot. at 24. As Respondent correctly notes, “it is well-established in the Vaccine Program that a petitioner’s failure to satisfy even a single Althen prong is dispositive. Resp. at 26 (citing LaLonde v. Sec’y of Health & Hum. Servs., 110 Fed. Cl. 184, 201 (2013), aff’d, 746 F.3d 1334 (Fed. Cir. 2014)); then citing Trollinger, 167 Fed. Cl. at 142; and then citing Hibbard, 698 F.3d at 1365). Petitioner must establish all three prongs of Althen by a preponderance of evidence, and failure to establish any one of them is dispositive. Oliver, 900 F.3d at 1361. Indeed, the Federal Circuit has repeatedly stated that a special master is not required to decide Althen prong three if he properly decided the Petitioner failed at prongs one or two. See Henkel v. Sec’y of Health & Hum. Servs., No. 2023-1894, 2024 WL 3873569, at *1 (Fed. Cir. Aug. 20, 2024) (“Because we conclude that the special master’s finding on Althen prong three was not arbitrary or capricious . . . and because Appellants needed to prevail on all three prongs to have their petition granted, we affirm the petition’s denial without reaching the prong-two finding.”); Koehn v. Sec’y of Health & Hum. Servs., 773 F.3d 1239, 1244 (Fed. Cir. 2014) (“Because [petitioner] failed to meet her burden under the third Althen prong, however, and failure to do so under any one of the Althen prongs is dispositive of this case, the Special Master correctly denied [petitioner’s] petition.”); Broekelschen, 618 F.3d at 1344, 1351 (affirming the special master’s decision where he determined the petitioner failed at prong one, and therefore declined to rule on prongs two and three); see also Trollinger, 167 Fed. Cl. at 142 (same); Contreras v. Sec’y of Health & Hum. Servs., 107 Fed. Cl. 280, 295 (2012) (citing Broekelschen, 618 F.3d at 1350–51) (“[T]here 51 Case 1:21-vv-01513-EMR Document 85 Filed 03/20/25 Page 52 of 52 is no per se rule forbidding a special master to deny compensation upon a finding that a petitioner has failed to meet one of the Althen prongs . . . .”); LaLonde, 110 Fed. Cl. at 206 (affirming petitioner failed to prove causation where it failed at prongs one and two, but where the special master agreed “there was a clear temporal relationship”). Accordingly, the Chief Special Master appropriately declined to consider Althen prong three in his Decision. On remand, he must only consider Althen prong three if his remand analysis of Althen prong one and prong two lead to a conclusion that Petitioner satisfied each of those prongs. CONCLUSION For the reasons stated above, Petitioner’s Motion for Review (ECF No. 76) is GRANTED IN PART. The Chief Special Master’s Decision (ECF No. 74) is VACATED and REMANDED for further action in accordance with this Memorandum and Order. Pursuant to 42 U.S.C. § 300aa- 12(e)(2)(C), the Chief Special Master shall issue a remand decision within 90 days. The parties are directed to CONFER and FILE a Notice within 14 days, attaching a proposed public version of this sealed Memorandum and Order. IT IS SO ORDERED. Eleni M. Roumel ELENI M. ROUMEL Judge Dated: February 26, 2025 Washington, D.C. 52 ================================================================================ DOCUMENT 4: USCOURTS-cofc-1_21-vv-01513-cl-extra-11091098 Date issued/filed: 2025-07-08 Pages: 1 Docket text: Supplementary opinion from CourtListener cluster 10624510 -------------------------------------------------------------------------------- In the United States Court of Federal Claims OFFICE OF SPECIAL MASTERS No. 21-1513V ************************* PORTIA EXUM, * Chief Special Master Corcoran * Petitioner, * Dated: May 27, 2025 * v. * * SECRETARY OF HEALTH AND * HUMAN SERVICES, * * Respondent. * * ************************* Amber Diane Wilson, Wilson Science Law, Washington, DC, for Petitioner. Mary Novakovic, U.S. Department of Justice, Washington, DC, for Respondent. DECISION ON REMAND 1 On June 25, 2021, Portia Exum filed a petition seeking compensation under the National Vaccine Injury Compensation Program (the “Vaccine Program”). 2 Petitioner alleges that the tetanus-diphtheria-acellular pertussis (“Tdap”) and measles-mumps-rubella (“MMR”) vaccines she received on August 20, 2018, caused her to develop autoimmune hepatitis (“AIH”). Pet. at 1. A one-day Entitlement Hearing was held on March 7, 2024, and after listening to the witnesses’ testimony and evaluating the record, I determined that Petitioner was not entitled to compensation. However, Petitioner prevailed on a motion for review, and the Court has ordered me on remand to more fully describe the rationale for my conclusions (including my decisions to accept, reject, and/or credit certain medical literature and expert testimony), and to revise my analysis pertaining to alternative causes. Remand Order, dated Feb. 26, 2025 (ECF No. 82) 1 Under Vaccine Rule 18(b), each party has fourteen (14) days within which to request redaction “of any information furnished by that party: (1) that is a trade secret or commercial or financial in substance and is privileged or confidential; or (2) that includes medical files or similar files, the disclosure of which would constitute a clearly unwarranted invasion of privacy.” Vaccine Rule 18(b). Otherwise, the whole Ruling will be available to the public in its present form. Id. 2 The Vaccine Program comprises Part 2 of the National Childhood Vaccine Injury Act of 1986, Pub. L. No. 99-660, 100 Stat. 3758, codified as amended at 42 U.S.C. §§ 300aa-10 through 34 (2012) (“Vaccine Act” or “the Act”). Individual section references hereafter will be to § 300aa of the Act (but will omit that statutory prefix). (“Remand Order”) at 44, 50–51. I have now done so—but I reach the same conclusion that I did after hearing. For, as discussed below, Petitioner was unable to preponderantly establish that the Tdap and MMR vaccines can cause AIH, or did so in her case. I. Factual Background Pre-Vaccination History Ms. Exum was born on January 29, 1988. Prior to the vaccinations at issue, she had a history of gastrointestinal reflux issues, small intestinal bacterial overgrowth, and kidney stones. Ex. 2 at 9–12; Ex. 3 at 273–75, 265–71. Notably, during a May 2018 ER visit for treatment of kidney stones, Petitioner’s AST and ALT levels (liver enzymes) were tested but found to be normal. Ex. 3 at 268. She also reported to an endocrinologist (who she saw in July 2018 for follow- up regarding her kidney stone issues) that she had been taking certain mushrooms as an immune booster, in anticipation of a trip she planned for later that year. Ex. 1 at 14. Petitioner began preparing for overseas travel to Kenya and Tanzania in mid-August 2018. See Declaration, dated June 8, 2021, filed as Ex. 11 (ECF No. 7-2) (“Exum Decl.”) at 1 ¶7. As part of that preparation, she received anti-malarial medication on August 17, 2018. Ex. 3 at 74. She was instructed to begin taking the medication two days before visiting areas with high risk for malaria, and to continue taking it for seven more days after leaving. Id. Three days later, on August 20, 2018, as additional preparation for her trip, she received the MMR and Tdap vaccines from her employer’s health clinic, but declined the typhoid vaccine. Id. at 72–73; Exum Decl. at 1 ¶7. Petitioner also at this time was provided traveler’s advisory information about risks of mosquito- borne illnesses, diarrhea, and “malaria prophylaxis.” Ex. 3 at 72. There is no medical record evidence that Petitioner experienced any immediate reaction to either of the vaccines she received on August 20th, or any notable symptoms in the more than one- week period before travelling abroad. Post-Vaccination Period and Symptoms Onset Petitioner traveled to Kenya and Tanzania as planned, from August 29 to September 8, 2018. Ex. 4 at 35; Exum Decl. at 1 ¶8. While abroad, she reports having received four or five bug bites. Ex. 4 at 35. Upon return, she felt fatigued, and had symptoms of gastroesophageal reflux disease (“GERD”) and indigestion in late September. Id.; Ex. 4 at 8. There is no other record evidence from the month of September suggesting Petitioner was experiencing unusual inflammation or signs of an infectious process. 2 Petitioner has alleged that she began to experience daily nausea in October 2018. Ex. 4 at 35; Exum Decl. at 1 ¶¶10–11. But there is no record evidence she sought treatment for it at this time. At most, in a medical encounter in January 2019, Petitioner stated that her nausea felt especially strong after a workout in mid-October. Ex. 4 at 8. Later that same month, on October 26, 2018 (now over two months since the vaccinations at issue—and six weeks after return from travel), Petitioner had a routine physical for life insurance purposes. The record from this visit memorializes no complaints or reports of gastrointestinal concerns, fatigue, or any other clinical symptoms. However, testing performed at this time revealed the presence of elevated liver enzymes. Ex. 4 at 42 (ALT of 818 U/L with a 0-45 U/L normal range, AST of 546 U/L with a 0-33 U/L normal range). She did not at this time, however, test positive for biomarkers supporting the presence of inflammation, like “BUN” or creatinine, 3 and she tested negative for Hepatitis C antibody (which would have suggested the presence of an acute or chronic infection that could result in liver disease). Id. at 40–41. Petitioner followed up with a gastroenterologist a month later, on November 28, 2018, to address both the elevated liver enzymes and her ongoing nausea, as well as related GI symptoms. Ex. 3 at 280. An abdominal exam was unremarkable, with no signs of liver enlargement or tenderness. Id. A physician’s assistant (“PA”) noted her recent abnormal liver function tests, however, and that Petitioner reported right-sided distress. Id. at 282. The PA recommended testing for an H. pylori bacterial infection, and that Petitioner try an over-the-counter anti-acid medication, plus diet modifications to ease her GERD and related symptoms. Id. Petitioner was also referred to a hepatologist to have an MRI of her liver. Id. at 283. Test results two days after this visit showed even higher AST and ALT levels, but yielded negative results for H. pylori. Id. at 67–69. Petitioner’s next treatment event occurred over five weeks later, at a visit to her primary care physician (“PCP”) on December 7, 2018. Ex. 3 at 61. She now reported upper right quadrant abdominal pain, nausea, fatigue, and yellow eyes. Id. An abdominal exam was unremarkable, and her PCP referred her to a hepatologist. Id. at 63. She also had her inter-uterine device (“IUD”) removed on December 6, 2018, to eliminate it as a potential source for her liver-related issues. Id. at 242–43. She then visited the same PCP on December 14, 2018. Id. at 57. She now reported that she had not completed the antimalarial drug course prescribed for her, and that some “doctor 3 The BUN (or “blood urea nitrogen”) test is used to measure the amount of urea nitrogen in the blood. See Blood Urea Nitrogen (BUN) Test, Mayo Clinic, https://www.mayoclinic.org/tests-procedures/blood-ureanitrogen/about/pac- 20384821 (last visited on May 27, 2025). Urea nitrogen is a chemical waste product usually removed from the body through the kidney, so a higher-than-normal BUN test result can stand as evidence that the kidneys or liver may not be working properly. Id. Creatinine is a chemical waste product produced by muscle metabolism, and also filtered out by the kidneys (and thus a high reading is further proof of kidney issues). See Creatine Test, Mayo Clinic, https://www.mayoclinic.org/tests-procedures/creatinine-test/about/pac-20384646 (last visited on May 27, 2025). An elevated BUN to creatinine measurement is evidence of blood volume depletion. McKown v. Sec. of Health & Human Services, No. 15-1451V, 2019 WL 4072113, at *15 (Fed. Cl. Spec. Mstr. July 15, 2019). 3 friends” of hers had expressed informal views that her condition could be the product of malaria or other insect diseases resulting from big bites she had received while in Tanzania. Id. The PCP ordered additional lab work, and referred her to an infectious disease specialist. Ex. 3 at 59. The lab work again showed elevated AST and ALT, but autoantibody testing for biomarkers associated with AIH (anti-nuclear antibodies and anti-smooth muscle antibodies) were negative. Id. at 58. On December 19, 2018, Petitioner saw hepatologist Dr. Omobonike Oloruntoba for evaluation of her elevated liver enzymes. Ex. 3 at 232–38. Petitioner denied the presence of known risk factors for liver disease, such as alcohol consumption or IV drug use, as well as any medicines or supplements (with the exception of “starting Reishi mushrooms” at some unspecified time). Id. at 232. She did, however, acknowledge taking antimalarial medication for ten days in connection with her oversees travel in August-September. Id. Dr. Oloruntoba noted that Petitioner displayed no signs of decompensated liver disease, including icterus, jaundice, confusion, melena, hematochezia, hematemesis, bruising, weight loss, or abdominal swelling, and an abdominal exam was again unremarkable. Ex. 3 at 232–33, 235. But a liver MRI revealed the presence of two hyper-intense lesions consistent with adenomas versus focal nodular hyperplasia (“FNH”), and asymmetric dilation of the left renal vein. Id. at 235–36. The diagnostic differential offered by Dr. Oloruntoba included “persistently elevated” liver function tests (“LFTs”), but with a “negative serologic work up,” deeming lab results to be “fortunately . . . not consistent with acute liver failure,” and hepatic adenoma versus FNH. Id. at 237. Additional lab results again showed elevated LFTs, but no signs of an active hepatitis infection. Ex. 8 at 73. Dr. Oloruntoba ordered a liver biopsy and a repeat liver MRI with contrast to be performed in six months. Ex. 3 at 237. Subsequent Treatment for Hepatitis Petitioner underwent the liver biopsy on January 3, 2019. Ex. 3 at 227–31. Results established the presence of “marked chronic inflammation,” as well as “patchy moderate interface necrosis.” Id. at 229. The findings were deemed by treaters to support a “broad differential diagnosis” that included “infection, the effects of medications/drugs/herbal remedies, Wilson disease, 4 and autoimmune hepatitis.” Ex. 3 at 229. 4 Wilson disease is a rare, inherited disorder in which the body fails to eliminate excess copper, leading to its accumulation in organs such as the liver or eyes. Wilson Disease, Dorland’s Medical Dictionary Online, https://www.dorlandsonline.com/dorland/definition?id=70938&searchterm=Wilson+disease (last visited on May 27, 2025). The build-up of copper can cause significant organ damage and various symptoms, including liver problems. Id. 4 The next day, Petitioner saw hematology and oncology specialist Dr. Charles Eisenbeis, who prepared a write-up/summary of his views on January 12, 2019. Ex. 3 at 221–26. The medical history obtained at this time was consistent with what is described above—that testing had begun to reveal abnormal LFTs in October 2018 and remained elevated thereafter, along with the liver MRI findings. Id. at 223. Dr. Eisenbeis also noted, however, that Ms. Exum had experienced no more than mild fatigue as a clinical symptom, and that she had not tested positive for the presence of hepatitis B or C. Id. And his own physical exam revealed nothing but the prior-reported nausea plus dyspepsia. Id. at 225. Dr. Eisenbeis observed elevated serum ferritin (iron) levels, which he attributed to “obvious liver disease” (adding that testing for a hereditary condition that could cause excess iron deposits was negative). Ex. 3 at 222. He also suggested Petitioner was experiencing hepatitis, but noted that “[w]orkup so far has been unrevealing for a cause of her liver disease.” Id. In mid-January, Petitioner received additional treatment for kidney stones and the lower quadrant pain/nausea she had previously reported. Ex. 2 at 28–30. Labs from this visit also revealed “very elevated” ALT and AST levels. Id. at 28. Petitioner also purports to have received an AIH diagnosis around this time frame—although no direct record proof has been offered in which Dr. Oloruntoba, or any other qualified hepatologist, is memorialized to have offered this diagnosis. On January 29, 2019, petitioner saw an infectious disease specialist, Henry Wu, M.D., for a second opinion regarding the purported AIH diagnosis she had just received. Ex. 4 at 6. At this time, her international travel from the early fall of 2018 was discussed, and she reported that she had entered bodies of water (“she did swim in the Indian Ocean and was in a bay to wade in the water to access the boats”), received several insect bites, and had felt extreme fatigue upon return. Id. at 8. Dr. Wu noted that Petitioner was taking a four-to-six-week course of prednisone. Id. at 6. He affirmed Petitioner’s hepatitis diagnosis (deeming it more likely chronic than attributable to an acute infection) and ordered lab work. Id. at 8. The results revealed Petitioner had experienced an Epstein-Barr viral infection at some prior point. Id. at 12; Ex. 3 at 207. Her LFTs had also improved but were still elevated. Ex. 3 at 204. Otherwise, no infectious explanation for Petitioner’s AIH could be identified. Id. at 7. Petitioner’s LFT levels thereafter trended downwards during February and March 2019. Ex. 3 at 43–51. During a GI visit for reflux management in February, Petitioner’s treater noted that she was taking kidney-oriented medication in addition to the prednisone to treat her liver issues. Id. at 197. Her PCP later noted in April 2019 that her AIH was “improving.” Id. at 36–37. A visit to a hepatologist that same month revealed continued LFT improvement, although levels remained above normal. Id. at 192–96. She also continued to report some ongoing fatigue. Id. at 34. 5 Petitioner visited her hepatologist again in August 2019. Ex. 3 at 162–65. Her LFTs remained elevated, and the hepatologist ordered a metabolic screen to rule out hepatoxicity, and instructed her to continue with her previously-prescribed medications. Id. at 165. Labs taken shortly thereafter in September 2019 showed slightly elevated LFTs, but otherwise normal results. Id. at 20–31. By the first half of 2020, Petitioner’s liver concerns had mostly resolved, and testing from this time to 2022 revealed normal LFTs. Ex. 10 at 56–61; Ex. 3 at 154. A repeat liver biopsy performed in February 2021, however, showed “chronic hepatitis with minimal interface activity and mild portal fibrosis (stage 1 of 4).” Ex. 14 at 41; Ex. 15 at 83. But a hepatology follow-up in March 2022 revealed no signs of liver disease, and the latest records filed in this case show no signs of liver disease through November 2023. Ex. 14 at 36–41; Ex. 46 at 6–7. II. Hearing Witnesses A. Petitioner’s Expert – Dr. Robert Gish, M.D. Dr. Gish prepared two reports in this case. Gish First Report, dated July 11, 2022, filed as Ex. 16 (ECF No. 18-1) (“First Gish Rep.”); Gish Supplemental Report, dated Mar. 21, 2023, filed as Ex. 38 (ECF No. 28-1) (“Second Gish Rep.”). He also testified at the hearing. Tr. at 5–116. Dr. Gish was the sole expert presented at trial in support of Petitioner’s claim. Dr. Gish received his M.D. from the University of Kansas, and completed his internship and residency at the University of California, San Diego. Curriculum Vitae, filed on July 11, 2022, as Ex. 37 (ECF No. 20-1) (“Gish CV”) at 3. He then completed a fellowship in gastroenterology and hepatology, with a special rotation in liver transplantation, at UCLA. Id. He is board-certified in internal medicine and gastroenterology, and has a separate board certification for hepatology that is part of the Certificate of Advanced Qualification in liver transplantation. Id. at 2. He is a member of multiple professional societies including the National Viral Hepatitis Round Table, the American Association for the Study of Liver Disease, and the American Liver Foundation. Id. at 4. He is a licensed physician in California, Arizona (inactive), and Nevada. Id. at 2. He has been active as a clinician and researcher for thirty-six years and has served on the editorial boards of many prestigious journals in his field, including Hepatology and the Journal of Viral Hepatitis. Gish First Rep. at 1. Presently, Dr. Gish is a Clinical Adjunct Professor of Medicine at the University of Nevada School of Medicine in both Reno and Las Vegas, and UCSD Skaggs School of Pharmacy and Pharmaceutical Sciences. Gish CV at 1. He is also the Medical Director of the Hepatitis B Foundation, which is the nation’s leading nonprofit research and advocacy organization for hepatitis B (HBV). Id. Dr. Gish acknowledged, however, that he is not an expert in immunology 6 (and significantly for purposes of this decision, no such expert was presented by Petitioner). Tr. at 90. Dr. Gish began his testimony by discussing Petitioner’s medical history prior to vaccination—which he deemed not to suggest the existence of developing liver disease or alternative causes. Tr. at 15. For example, she had no physical exam results indicating liver issues, and four normal liver panel tests before receiving the vaccine. Id. When a patient has normal liver enzyme tests, “the chance of that person having active liver disease that is hidden in some way is extremely small.” Id. at 18. He also noted that liver disease patients typically present with symptoms like fatigue, liver pain, jaundice, rashes, and mental confusion. Id. at 19. When reviewing Petitioner’s medical history, Dr. Gish looked for common causes of liver disease, such as alcoholism, needle sharing, high-risk sexual behavior, and having medical procedures in developing countries—but no such factors were evident. Id. at 19–20. Dr. Gish further pointed out that Petitioner had tested negative for Epstein-Barr virus and Hepatitis B and C, which are also significant risk factors. Id. at 22. Dr. Gish admitted that Petitioner’s receipt of anti-malarial medication before traveling to Africa was a risk factor for AIH, “but that’s typically brief, transient, and doesn’t result in autoimmune disease long-term.” Tr. at 22. He compared Petitioner’s course to that of the patient in a case report whose hepatitis presented acutely after taking an anti-malarial medication. Id.; B. Beretta-Piccoli et al., Atovaquone/Proguanil-Induced Autoimmune-Like Hepatitis, 1 Hepatology Comm. 293 (2017), filed as Ex. A Tab 10 (ECF No. 25-10) (“Beretta-Piccoli”). The patient evaluated in Beretta-Piccoli displayed symptoms like jaundice and dark urine—obvious clinical signs of liver disease, but unlike Petitioner (at least when her elevated LFT levels were first observed). Tr. at 82; Beretta-Piccoli at 293. Further, Petitioner had already stopped taking all of her medications and supplements after receiving her October 2018 lab results. Tr. at 80. Thus, had the two herbal supplements Petitioner had been taking caused her elevated liver enzymes, the levels should have normalized once she stopped taking them—but she continued to have elevated liver enzymes. Id. The above, plus Dr. Gish’s view that her disease onset had begun within a few weeks of vaccination, permitted him to conclude that she fit the “ideal profile” for an adverse reaction to the vaccine. Id. at 22. In proposing how the vaccines Petitioner received could have caused AIH, Dr. Gish focused on the measles component of the MMR vaccine as capable of triggering an immune- mediated disease process. Tr. at 38. AIH, he maintained, would usually be initiated by some kind of environmental trigger. Id. at 23. The MMR vaccine Petitioner received is an attenuated but live vaccine, which contains components that can “live in the body as a virus” and thereby “manipulate the immune system.” Id. at 35; First Gish Rep. at 11. As a result, the measles component could temporarily suppress the immune system so that the virus can replicate and persist. Tr. at 36. In an individual with a functioning immune system, regulatory safeguards can turn back on, regulating 7 the virus and shutting down the immune response. Id. But Petitioner’s immune response remained chronically activated. Id. at 49. In support, Dr. Gish pointed to filed literature that he maintained established the capacity of the MMR vaccine to suppress the immune response, in ways comparable to the wild measles virus. Tr. at 38–42; R. Nanan et al., Measles Virus Infection Causes Transient Depletion of Activated T. Cells from Peripheral Circulation, 12 J. of Clin. Virology 201 (1999), filed as Ex. 31 (ECF No. 19-7) (“Nanan”); T. Munyer et al., Depressed Lymphocyte Function after Measles- Mumps-Rubella Vaccination, 132 J. of Infectious Diseases 75 (1975), filed as Ex. 32 (ECF No. 19-8) (“Munyer”); First Gish Rep. at 22 (“[s]ufficient clinical studies confirm that MMR vaccine, even though attenuated, can induce a temporary immune suppression that can last for months”). Here, the suppression of bystander immune cells by the measles virus component of the vaccine allowed an autoimmune cross-reaction to occur. Tr. at 58. Dr. Gish proposed that the pathogenic mechanism responsible for the onset of Petitioner’s AIH involved the breaking of self- tolerance to hepatic autoantigens (located on the surface or in the mitochondria of liver cells). Id. at 54–55. Normally, a healthy person’s immune cells will not cross-react with these hepatic autoantigens, in part from T cell regulation. Id. But when T cells are dysregulated, they can incorrectly recognize the hepatic autoantigens on a person’s liver cells as being foreign—and attack them. Id. at 58. Dr. Gish thus theorized that, in clearing the vaccine-induced measles infection from Petitioner’s body, non-measles specific immune cells remained chronically activated thereafter, resulting in a persistent autoimmune condition affecting her liver. Id. at 46– 49. In addition, Dr. Gish maintained that the measles component of the MMR vaccine could directly infect immune cells. Tr. at 38; L. Rennick, Live-Attenuated Measles Virus Vaccine Targets Dendritic Cells and Macrophages in Muscle of Nonhuman Primates, 89 J. of Virology 2192-2000 (2015), filed as Ex. 33 (ECF No. 19-9) (“Rennick”). This was additional confirmation of the possibility that the measles virus could not only persist in the body post-vaccination but could negatively impact immune function (or at least engage in ongoing immune suppression). First Gish Rep. at 20, 23. An autoimmune reaction to the measles vaccine was likely compounded by Petitioner’s simultaneous receipt of the Tdap vaccine. Tr. at 62. 5 Petitioner’s age and records confirmed for 5 Dr. Gish’s initial report also suggested that an adjuvant (a compound included in a vaccine to boost immunogenicity) in the Tdap or MMR vaccine may have also played a role in causing injury. First Gish Rep. at 10, 21, 23. However, at trial he explicitly stepped away from reliance on this possible mechanism. Tr. at 60, 166–68. This was wise—the Program has consistently rejected causation theories relying on the pathogenic impact of vaccine adjuvants. McKown v. Sec'y of Health & Hum. Servs., No. 15-1451V, 2019 WL 4072113, at *50 (Fed. Cl. Spec. Mstr. July 15, 2019) (noting that the ASIA theory, “which posits the aluminum vaccine adjuvant as contributing to the purported pathologic immune response, is especially suspect from a scientific standpoint”) (citations omitted). 8 Dr. Gish the fact that Petitioner had previously received a whole cell pertussis-containing vaccine (since replaced by the acellular form due to concerns about adverse events). First Gish Rep. at 12, 21–22. Studies have established the need for pertussis boosters to maintain immunity—and also that production of a specific kind of T helper cell 6 “believed to play an important role in the development of a variety of autoimmune diseases, including autoimmune liver disease” is encouraged in individuals who had previously received the whole cell pertussis form of the vaccine, but then receive as a booster the acellular form. Id. at 22; F. Lafdil et al., Th17 Cells and Their Associated Cytokines in Liver Diseases, 7 Cellular & Molecular Immuno. 250–54 (2010) (ECF No. 20-2) (“Lafdil”). 7 The antigen-specific response generated by this booster vaccine may have amplified the existing response to the measles vaccine, and also itself peaked more quickly (since Petitioner was receiving a booster). Tr. at 62; First Gish Rep. at 23. As additional support for causation, Dr. Gish relied on a number of case reports (discussed below). He deemed them reasonable evidence of causation under the circumstances, since vaccine injury was rare as a general matter, and given the absence of relevant larger-scale epidemiologic studies. Second Gish Rep. at 1–2. Case reports, he proposed, were at least “signals of issues to be aware of” for clinicians, and they stood as real-world evidence of how a proposed theory might actually unfold. Id. at 2, 3 (“if something did happen in another person, then logically the event can happen in this patient”). At the same time, Dr. Gish accepted the possibility of mere coincidence between receipt of a vaccine and development of AIH. Id. at 1. Dr. Gish then briefly discussed an item of literature that he proposed established a secondary explanation for how an individual like Petitioner might experience AIH. See S. Subramanian et al., Postinfectious Autoimmune Hepatitis-Induced Liver Failure: A Consequence of Hepatitis A Virus Infection, 7 ACG Case Reports J. 1 (2020), filed as Ex. 25 (ECF No. 19-1) (“Subramanian”). But he did not reference Subramanian for its primary findings (which focused on how a hepatitis A wild virus infection could secondarily result in autoimmune hepatitis), but instead for a separate item of literature it discussed, “Vento” (which Petitioner never filed in this case). 8 In Vento, researchers followed family groups that developed autoimmune hepatitis after hepatitis A infections. Tr. at 66–68. The results of the Vento study supported the concept that a genetic disposition could render patients susceptible to AIH, and Dr. Gish felt that this in turn 6 T helper cells are a kind of immune cell that assist B cells in the production of antibodies. Zacharski v. Sec'y of Health & Hum. Servs., No. 21-317V, 2025 WL 1235431, at *18 (Fed. Cl. Spec. Mstr. Mar. 26, 2025). They serve a different purpose from the type of T cells responsible for directly attacking foreign pathogens. 7 Although Lafdil is identified on Petitioner’s Exhibit List (ECF No. 45-4) as Exhibit 35, it is erroneously marked as Ex. 36 in the filed copy. 8 See Exhibit List, filed December 26, 2023 (ECF No. 45-4). Despite the fact that Vento was never filed as evidence in this case, Dr. Gish characterized it as a “very, very interesting and compelling report,” as well as “a[n] excellent paper that would describe what happened to Ms. Exum.” Tr. at 67, 69. It is exceedingly difficult to understand why Petitioner (despite demonstrated opportunity) never chose to file this article, if it is in fact so compelling and persuasive. 9 suggested that Petitioner was likely genetically susceptible as well. Id. at 69. But he admitted that no genetic testing had been performed that would corroborate the contention about Petitioner’s susceptibility. Id. at 96. (And of course, as already noted, the vaccines Petitioner received did not include hepatitis A). Dr. Gish also reviewed Petitioner’s clinical course, deeming it consistent with his causal theory. Tr. at 70. In particular, he opined that Petitioner’s AIH symptoms onset began within an acceptable timeframe for an environmental trigger (in this case the vaccine). Id. He pointed to Petitioner’s fluctuating but elevated liver enzymes (as evidenced by test results obtained between October 2018 and January 2019) as establishing the existence of ongoing AIH, confirmed by the biopsy taken in January 2019. Id. at 70–74, 75. Thus, he concluded that “the timing of symptoms, the timing of laboratory tests, the liver biopsy, all fits a classic triggering event and onset of autoimmune disease.” Id. at 82. Dr. Gish did not provide a precise proposal for Petitioner’s most likely true onset, however. On the one hand, in his first expert report he seemed to embrace the discovery of elevated LFT results, in connection with Petitioner’s October 26, 2018 physical exam (occurring 68 days post- vaccination) as a significant evidentiary point establishing the presence of AIH at that time. First Gish Rep. at 24; Second Gish Rep. at 10. But during the hearing, he refined his view, maintaining that onset likely occurred sometime before these testing results were obtained. Tr. at 114. Ultimately, Dr. Gish seemed to embrace any onset as occurring within ten weeks of vaccination as medically acceptable. Id. at 70. But he also seemed to view a timeframe of up to five or six months as acceptable, based on science suggesting that the immune response could remain robust for such a period of time. Second Gish Rep. at 10; Claire-Anne Siegrist, Vaccine Immunology, in Plotkin’s Vaccines 16-34 (S. Plotkin et al. eds., 7th ed. 2018) (“Siegrist”), filed as Ex. 20 (ECF No. 18-5). On cross-examination, Dr. Gish acknowledged that he has seen patients who developed AIH after traveling, and after taking herbal supplements as well. Tr. at 91–92. He denied that Petitioner’s previous small bowel overgrowth (“SIBO”) could have caused her AIH, explaining that SIBO is linked to a specific type of AIH which Petitioner did not have. Id. at 94. He acknowledged that Petitioner’s AIH could have been idiopathic, however, and admitted that an environmental trigger can typically only be identified in half of cases. Id. at 95. When asked about the molecular mimicry aspect of his causal theory, Dr. Gish agreed that he had not identified a specific homology between any amino acid sequences found in proteins of the relevant vaccine components and liver proteins. Tr. at 108. He also attempted to further explain the immune suppression mentioned in his earlier testimony and report, and how the MMR vaccine “both suppresses and activates the immune system” at the same time. Id. at 112–16. He specified that the innate immune response is suppressed, leading the adaptive immune response to 10 compensate. Id. at 113. Concurrently, a variety of antigen-presenting cells are activated, producing “off-target effects.” Id. Then, in a genetically susceptible individual, “[y]ou end up stimulating an arm of the immune system that isn’t getting turned off. These are the T-regs that are suppressed in some ways or can[no]t be activated and the immune system goes down this long pathway.” Id. B. Respondent’s Experts 1. Jeffrey Crippin, M.D. — Dr. Crippin authored one report in this case, and testified at the hearing. Crippin Report, dated Oct. 31, 2022, filed as Ex. A (ECF No. 23-1) (“Crippin Rep.”); Tr. 117–41. Dr. Crippin received his medical degree from the University of Kansas, and completed an internal medicine residency at Kansas University Medical Center, where he served as chief resident. Curriculum Vitae, dated Mar. 4, 2024, filed as Ex. E (ECF No. 56-1) (“Crippin CV”) at 1–2. He then completed a three-year fellowship in Gastroenterology and Hepatology at the Mayo Clinic in Rochester, Minnesota. Crippin CV at 2. He currently works at the Barnes-Jewish Hospital in St. Louis, and is a Professor of Medicine at the Washington University School of Medicine. Id. at 1. He is board certified in internal medicine and gastroenterology, and has received the Certificate of Added Qualification in transplant hepatology. Id. at 6–7. He has extensive experience in treating patients with autoimmune hepatitis—he has treated 300–400 patients with the disease over the course of his career. Crippin Rep. at 1. Dr. Crippin agreed with Petitioner’s AIH diagnosis, but denied that the vaccines she received were more likely than not the cause of her illness. Tr. at 123. Rather, he pointed out numerous other potential causal factors in her record, although he was unable to specify one as most likely. Id. at 125–27. These factors included Petitioner’s international travel in the months prior to her illness; her use of anti-malarial medication and herbal supplements; and a prior history of kidney stones, an IUD, and her SIBO. Id. at 125–27, 128–29. Further, she had tested positive for Epstein-Barr virus antibodies in December 2018. Id. at 127; Ex. 3 at 207. Dr. Crippin admitted, however, that it was impossible to determine when she had Epstein-Barr from that test (“[i]t could have been earlier that year, it could have been five years ago”). Tr. at 127. Although Petitioner experienced fatigue (a symptom of the virus) upon returning from travel, she was not tested for the virus at the time. Id. at 128. He also noted that a large number of AIH cases are idiopathic, meaning that no specific trigger can be identified. Id. at 130. Dr. Crippin then discussed one of the case reports Petitioner filed most relevant to this case, pointing out differences from Petitioner’s clinical course. Tr. at 131; W. Saliba & M. Elias, Acute Hepatitis Following MMR Vaccination, 16 Euro. J. of Internal Med. 379 (2005), filed as Ex. 21 (ECF No. 18-6) (“Saliba”). Although Saliba involved the MMR vaccine, it featured a patient who experienced acute hepatitis rather than AIH, with a post-vaccination onset of two weeks (not the 11 six to eight weeks likely in this case). Tr. at 131–32; Saliba at 379. The Saliba patient had also recently given birth, putting her at greater risk of viruses due to pregnancy-related immune suppression, and no liver biopsy was performed to help determine the cause of her hepatitis. Tr. at 131–32; Saliba at 379. Dr. Crippin also noted that he had been unable to locate any controlled studies showing a link between AIH and either the MMR or Tdap vaccines. Tr. at 130. And he similarly was unaware of studies establishing that the combined administration of both vaccines at once constituted a risk factor for AIH. Id. at 133. On cross, he reiterated his prior testimony that he could not determine when Petitioner was infected with Epstein-Barr virus, and that there were no other infections noted in her records. Id. at 135. Ultimately, Dr. Crippin declined to identify which of the various factors he deemed the most likely cause, and stated again that this could be an idiopathic case. Id. at 137– 38, 140–41. 2. Andrew MacGinnitie, M.D., Ph.D. — Dr. MacGinnitie wrote one report in this case, and testified at the hearing. MacGinnitie Report, dated Oct. 27, 2022, filed as Ex. C (ECF No. 23-3) (“MacGinnitie Rep.”); Tr. at 141–92. Dr. MacGinnitie is the Chief of the Division of Allergy, Asthma, and Immunology at Children’s Hospital of Wisconsin, and a Professor of Pediatrics at Medical College of Wisconsin. Tr. at 142–43. He graduated from the University of Chicago Pritzker School of Medicine with both an M.D. and a Ph.D. from the Department of Pathology. Curriculum Vitae, dated Oct. 31, 2022, filed as Ex. D (ECF No. 23-4) (“MacGinnitie CV”). He then completed a residency in pediatrics in the Boston Combined Residency Program, training at Boston Children’s Hospital and Boston Medical Center, followed by an allergy/immunology fellowship at Boston Children’s Hospital. Id. at 1. He is board certified in both allergy/immunology and pediatrics. Id. at 11. He maintains an active clinical practice seeing more than 1600 patients annually and has extensive experience in caring for children and adults with a variety of immunologic diseases, including reactions to vaccines. MacGinnitie Rep. at 2. Dr. MacGinnitie also performs research and has published articles in a number of areas related to allergy/immunology including food allergy, vaccine reactions, and primary immunodeficiency. Id. Dr. MacGinnitie was the sole immunology expert to offer testimony in this case. Dr. MacGinnitie opined that the vaccines Petitioner received had no likely relationship to her AIH. Tr. at 148. First, he criticized Dr. Gish’s reliance on case reports (in the absence of epidemiological studies connecting AIH and the Tdap and MMR vaccines). Id. at 150. In his view, case reports cannot reliably connect a vaccine to an illness because they do not provide an accurate comparison with the baseline rate of an illness in the general population. Id. Further, none of the case studies filed involved instances of simultaneous administration of the Tdap and MMR vaccines. Id. at 151; see, e.g., M. van Gemeren et al., Vaccine-Related Autoimmune Hepatitis: The 12 Same Disease as Idiopathic Autoimmune Hepatitis? Two Clinical Reports and Review, 52 Scandinavian J. of Gastroenterology 18 (2017) (involving a combination of Tdap and hepatitis A vaccines), filed as Ex. 26 (ECF No. 19-2) (“van Gemeren”); see also P. Perumalswami et al., Vaccination as a Triggering Event for Autoimmune Hepatitis, 29 Seminars in Liver Disease 331 (2009) (discussing hepatitis A and yellow fever vaccines), filed as Ex. 27 (ECF No. 61) (“Perumalswami”). And although Saliba did involve the MMR vaccine, the relevant patient only experienced an acute form of hepatitis. Tr. at 152; Saliba at 379. In another case report offered by Dr. Gish, the patient received six vaccines at the same time, and although the MMR vaccine was one of them, it was impossible to isolate the effects of only one or two of the listed vaccines. Tr. at 152–53; G. Veerappan et al., Vaccination-Induced Autoimmune Hepatitis, 50 Digestive Diseases and Sci. 212 (2005), filed as Ex. 24 (ECF No. 58-1) (“Veerappan”). Second, Dr. MacGinnitie took issue with Petitioner’s invocation of molecular mimicry as a possible mechanism for vaccine-induced AIH. Tr. at 156. After explaining the concept briefly, he noted that Dr. Gish had not identified any specific homology (meaning molecular similarity) between amino acid sequences in the vaccines’ protein components and the liver cell antigens where an autoimmune cross-reaction would begin or occur—a crucial starting point if molecular mimicry was to stand as a reasonable explanation for Petitioner’s injury. Id. at 158. Moreover, even a demonstration of homology would not be sufficient to prove the theory in Dr. MacGinnitie’s view, as there is a “massive overlap between microbial and human proteins” in nature that does not commonly result in autoimmunity. Id. He also criticized Petitioner’s reliance on bystander activation of secondary/nonspecific immune cells as a possible disease mechanism, noting that articles filed in the case specific to AIH did not consider this to be a pathologic explanation. Id. at 160; C. Mack et al., Diagnosis and Management of Autoimmune Hepatitis in Adults and Children: 2019 Practice Guidance and Guidelines from the American Association for the Study of Liver Diseases, 72 Hepatology 671 (2020), filed as Ex. A, Tab 1 (ECF No. 25-1) (“Mack”). Beyond this, Petitioner had not displayed clinical signs of significant inflammation, which would have occurred shortly after vaccination had such an autoimmune response been underway. Tr. at 159. Dr. MacGinnitie also addressed Petitioner’s argument that her immune system was likely suppressed by the measles vaccine, allowing an autoimmune response to occur. He noted the absence of strong evidence showing that the measles vaccine (as opposed to the wild virus) suppresses the immune system pathologically. Tr. at 162; MacGinnitie Rep. at 8–9. He deemed articles filed to support this contention as lacking in clinical value and/or outdated. Tr. at 162–64; Nanan (published in 1999); Munyer (published in 1975). Up-to-date clinical manuals relied upon by treaters, however, acknowledge the immune-suppressive nature of the wild measles virus, but not the vaccine (the receipt of which functions to prevent this immune suppression in the first place). Tr. at 165–66; American Academy of Pediatrics, Red Book (2021): Report of the Committee on Infectious Diseases 503 (32d ed. 2021), filed as Ex. C, Tab 4 (ECF No. 26-4) (“AC of Pediatrics”); see also M. Mina, Measles, Immune Suppression, and Vaccination: Direct and 13 Indirect Nonspecific Vaccine Benefits, 74 J. Infection S10, S15 (2017), filed as Ex. C, Tab 3 (ECF No. 26-3) (“Mina”) (noting the benefit of measles vaccine in blunting the immunosuppressive character of a wild measles virus infection). Dr. MacGinnitie also noted that a theory dependent on immunosuppression did not fit with AIH’s likely pathogenesis. Since AIH is considered autoimmune in character, it reflects an aberrantly overstimulated/overactive immune process—not one that has been suppressed (allowing another opportunistic infectious process might occur). Tr. at 162. Dr. MacGinnitie challenged Dr. Gish’s argument that whole cell pertussis 9 could itself stimulate a class of T-helper cells (which encourage the production of certain proinflammatory cytokines)—and thus, because Petitioner had likely received the whole cell pertussis vaccine as a child, the Tdap booster she had received in 2018 might have increased the possibility of a comparable immune memory response. Tr. at 169. He acknowledged the importance of the relevant T-helper cells in fighting bacterial and fungal infections, but deemed the re-stimulation of them unlikely to cause autoimmune disease. Id. at 170. Thus, although Petitioner had offered a study showing that patients vaccinated with whole cell pertussis produced more inflammatory cytokines than those initially vaccinated with acellular pertussis, the study did not also establish that the produced cytokines rose to levels anywhere near sufficient to propagate an autoimmune inflammatory environment. Id. at 171–72; R. da Silva Antunes et al., Th1/Th17 Polarization Persists Following Whole-Cell Pertussis Vaccination Despite Repeated Acellular Boosters, 128 J. Clin. Investigation 3853 (2018), filed as Ex. 34 (20-1) (“da Silva Antunes”). And since Petitioner had not been tested for these cytokines, it was pure speculation to propose she likely possessed them in pathologic levels after vaccination. Tr. at 173. Dr. MacGinnitie concluded with a brief consideration of the onset interval of one to five months Dr. Gish proposed for vaccine-induced AIH. Tr. at 174. Although he opined that case reports should carry little evidentiary weight, he noted that the case reports Dr. Gish cited showed documented hepatitis (not simply the first symptoms) beginning within a far shorter timeframe: ten to thirty days of vaccination. Id.; see, e.g., T. Sasaki et al., Autoimmune Hepatitis Following Influenza Virus Vaccination: Two Case Reports, 97 Med. 1 (2018), filed as Ex. 28 (ECF No. 19- 4) (“Sasaki”) (documenting one week onset and one month onset). Other items of literature Petitioner referenced for a shorter onset timeframe involved distinguishable diseases or vaccines. Tr. at 175–76; L. Schonberger et al., Guillain-Barré Syndrome Following Vaccination in the National Influenza Immunization Program, United States, 1976-1977, 110 Am. J. of Epidemiology 105, filed as Ex. 39 (ECF No. 28-2) (“Schonberger”) (discussing the flu vaccine and Guillain- Barré syndrome (“GBS”)). 9 The now largely-discontinued DPT vaccine included whole cell pertussis, but the version administered today (Tdap) employs an acellular form of pertussis thought to be less likely to cause certain side effects. See Andreu v. Sec'y of Health & Hum. Servs., 569 F.3d 1367, 1375 n.1 (Fed. Cir. 2009) for discussion of case law on the safety concerns prompting the switch to an acellular formulation. 14 III. Review of Filed Literature Ample Program authority establishes that special masters are not required to describe and/or analyze in a written decision every item of literature filed in support of or against a claim. See, e.g., Snyder v. Sec'y of Health and Hum. Servs., 36 Fed. Cl. 461, 466 (1996), aff'd, 117 F.3d 545 (Fed. Cir. 1997). Indeed, the failure to specifically mention a filed item in a decision does not allow for the inference that it was not included in the special master’s overall weighing of evidence. Hazlehurst v. Sec'y of Health and Hum. Servs., 604 F.3d 1343, 1352 (Fed. Cir. 2010) (noting that a reviewing court presumes that the fact finder has considered all of the material in the record, regardless of whether it is individually mentioned in his or her decision); see also Moriarty v. Sec’y of Health & Hum. Servs., No. 2015–5072, 2016 WL 1358616, at *5 (Fed. Cir. Apr. 6, 2016) (“[w]e generally presume that a special master considered the relevant record evidence even though he does not explicitly reference such evidence in his decision”) (citation omitted); Paterek v. Sec’y of Health & Hum. Servs., 527 F. App’x 875, 884 (Fed. Cir. 2013) (“[f]inding certain information not relevant does not lead to—and likely undermines—the conclusion that it was not considered”). There is also the fact that this matter went to a live hearing. A hearing provides the parties the opportunity to succinctly but fully explain their take on a case in the best possible manner. In holding hearings, special masters reasonably focus their attention on the items of literature the parties deem most worthy of verbal mention during an expert’s testimony. Presenting an entitlement claim is not a game of “hiding the ball,” where a claimant seeds the record with numerous items of literature, references only some at hearing, and then later objects on appeal when certain filed items do not receive a full airing in a written decision. Echols v. Sec’y of Health & Hum. Servs., 165 Fed. Cl. 9, 12 (2023) (“the evidence heard by the special master should be the “main event” rather than a mere “tryout”). The Remand Order nevertheless has identified some items of literature as requiring more discussion, in order to disclose the full extent of my reasoning. Remand Order at 40–44. Accordingly—and because I ultimately reach the same conclusion that I initially did—I will provide a detailed summary of every single item of literature filed by Petitioner in this case. 10 10 Petitioner filed a relatively modest 22 articles or studies. See Petitioner’s Exhibit List as of December 26, 2023, filed Feb. 9, 2024 (ECF No. 53-2). 15 A. Petitioner’s Literature 11 1. Mack Both sides offered this article. Mack provides an overview of AIH, and guidelines for its diagnosis and treatment. See generally Mack. Petitioner offered Mack to explain AIH’s immunopathogenesis, and to establish that Petitioner was properly diagnosed with AIH. First Gish Rep. at 7. But Petitioner’s diagnosis is not questioned in this case. To the extent Mack bears on causation, it is discussed in greater detail in the analysis section of this Decision. 2. U. Christen & E. Hintermann, Pathogens and Autoimmune Hepatitis, 195 Clin. and Experimental Immuno. 35-51 (2019), filed as Ex. 18 (ECF No. 18-3) (“Christen”). Petitioner has offered Christen in support of her argument that multiple viruses, including the measles virus, are implicated in the pathogenesis of AIH. First Gish Rep. at 10. Christen is a review article discussing some of the possible environmental triggers for AIH. Christen at 35. Unquestionably, the article mentions “pathogen infections and vaccinations” as possible environmental factors that can interact with a preexisting genetic risk factor. But Christen solely discusses wild viral or bacterial pathogens, focusing on the most obvious (hepatitis viruses) or the Epstein-Barr virus. Id. at 40–43. In a brief section addressing “other pathogens” possibly capable of triggering AIH, Christen notes the existence of “two studies from the 1980s” in which AIH patients were found to possess evidence of a measles virus infection, but adds that the studies relied on diagnostic definitions for AIH that would no longer be valid—and that another epidemiologic study had subsequently revealed “no significant difference” between a studied population and AIH patients who generated measles virus antibodies. Christen at 43. 12 At most, Christen posits that some case reports involving AIH after a measles infection allow for the hypothetical possibility of measles virus as an infectious trigger—although the sole reference for this case report is the same article mentioned by Dr. Gish but never filed, Vento. Id. at 43 n.111. Christen also acknowledges that little evidence supports the hypothesis that AIH is driven by molecular mimicry, although (unlike Mack) Christen does mention bystander activation, at least as a theoretical mechanism. Id. at 37, 38. 11 I refer to an article’s abbreviated title in all cases where the item was previously defined in this manner in this Decision. 12 Petitioner filed one of the two 1980s articles referenced herein—Robertson (see Christen at 43 n.109), plus the epidemiologic article that Christen notes undermined a measles virus—AIH connection (Mieli-Vergani I—Christen at 43 n.110). Both are discussed below. 16 3. C. Benn et al., A Small Jab – A Big Effect: Nonspecific Immunomodulation by Vaccines, 34 Trends in Immuno. 431-39 (2013), filed as Ex. 19 (ECF No. 18-4) (“Benn”). Petitioner cites Benn to support her contention that vaccines can activate nonspecific bystander immune cells. First Gish Rep at 10. Benn notes that “[r]ecent epidemiological studies have shown that, in addition to disease-specific effects, vaccines against infectious diseases have nonspecific effects on the ability of the immune system to handle other pathogens.” Benn at 431. The authors of Benn explain that each exposure to infection or vaccination leaves an imprint on a person’s immune system, which can affect future innate and adaptive responses to new pathogens. Id. at 433. This concept of “heterologous immunity” could explain why vaccines may have nonspecific effects—because the vaccines encode antigens that cross-react with other pathogens. Id. The authors conclude, therefore, that cross-reactive T-cell-mediated heterologous immunity is likely a common determinant in the pathogenesis of infections. Id. at 433–34. Benn, however, primarily focuses on the positive rather than pathologic indirect effects of vaccination. In Benn’s discussion of the measles vaccine, for example, the authors emphasize the vaccine’s observed survival benefits. Benn at 432, 436 (“[e]xisting studies suggest a general pattern, namely that the live vaccines: [including measles vaccine] are associated with beneficial nonspecific effects, leading to reduced all-cause mortality . . . .” (emphasis added)). Measles- vaccinated children have substantially lower mortality than can be explained by measles-related deaths, suggesting that the vaccine comes with a host of nonspecific beneficial effects. Id. at 432. Benn does not purport to state how vaccines most likely induce these nonspecific effects, but it does not support the conclusion that the live vaccines it discusses have pathologic potential due to their nonspecific effects (at best allowing for the need to identify when those effects could be detrimental, so that concurrent therapeutic interventions could be developed to inhibit negative outcomes). Id. at 437. 13 And Benn says nothing specific about AIH and its purported vaccine association. 4. Siegrist Siegrist is an excerpt from a larger publication, and it provides a general explanation for how a vaccine activates the immune system. Among other things, it highlights the role of T cells in the induction of high-affinity antibodies and immune memory. Siegrist at 16. It also notes that live vaccines (like MMR) “rapidly disseminate throughout the vascular network to reach their target tissues” in a pattern that is “very similar to that occurring after a natural infection.” Id. at 20. 13 At most, Benn contains a discussion of some instances where “detrimental heterologous immunity can lead to severe immunopathology.” Benn at 434. But the instances discussed involve studies featuring immunization of animal subjects with different vaccines, resulting in other forms of disease not bearing on this case, or where receipt of one form of a vaccine can “lock” an immune response to subsequent forms, causing a vaccine to have “detrimental effects on the outcome of secondary infections.” Id. at 435. 17 But Siegrist also, in Petitioner’s estimation, has something to say about the impact of receipt of the non-live, Tdap vaccine. She received Adacel, a Tdap booster, and that vaccine was expected to activate Petitioner’s immune memory cells and result in a rapid increase of antibody titer. First Gish Rep. at 23. According to Figure 2.3 in Siegrist, booster exposure to antigen reactivates immune memory and results in an increase of IgG antibody titer within seven days of receipt. Siegrist at 24. Short-lived plasma cells responsible for production of antibodies thereafter maintain peak antibody levels for a few weeks. Id. And six months after booster vaccination, long- lived plasma cells reach survival niches in the bone marrow and continue to produce antigen specific antibodies. Id. Petitioner cited to Siegrist to support her arguments about the medically-acceptable timeframe in which her AIH manifested post-vaccination. First Gish Rep. at 24. Petitioner started to experience fatigue in the weeks after vaccination, but then continued to suffer increased symptoms in the five months up to her formal diagnosis in January 2019. Petitioner argues that this symptom progression fits within the one to five-month timeframe suggested in Siegrist. First Gish Rep. at 24. 5. Saliba As discussed above, Petitioner has offered Saliba to support her argument that the MMR vaccine can cause a person to develop hepatitis. Saliba is a one-page “letter to the editor” which reports an instance in which a 24-year-old woman developed acute hepatitis two weeks after receiving the MMR vaccine, with her hepatitis thereafter resolving within a month (as reflected by LFT results). Saliba at 379. The sequence of events, together with the lack of potential causes for elevated liver enzymes, “strongly suggest[ed]” to its authors that the patient’s development of hepatitis was related to vaccination. Id. The proposed mechanism was a cytotoxic, cell-mediated, immunological response with injury of the hepatocytes. Id. But Saliba notes (at least as of the time of its publication) that “there is still no evidence that [the vaccine’s viral components] are directly cytopathic to the hepatocytes,” although it referenced an older article (not filed in this case) purportedly establishing that biopsies of patients with rubella infection have revealed “necrosis of liver cells” and suggesting that “cytotoxin T cell lymphocytes play an important role in liver injury.” Id. Saliba’s short onset timeframe is self-evidently distinguishable from this case. 6. J. McMahon et al., Measles Vaccine Virus RNA in Children More Than 100 Days after Vaccination, 11 Viruses 636-48 (2019), filed as Ex. 22 (ECF No. 18-7) (“McMahon”). McMahon is another instance of an article cited by Petitioner as supporting a point that the article itself only stands for secondarily. Noting the general dangers of a wild measles infection (especially because of its immunosuppressive character), and the corresponding benefit of the measles vaccine, McMahon’s authors evaluated some instances of “extremely delayed” detection 18 of the measles vaccine in a sample of more than 9,000 children. McMahon at 638-39. Ordinarily, RNA from a measles virus strain found in the vaccine is commonly detected for up to at least 14 days post-vaccination. Id. at 638, 643. But McMahon confirmed that the strain can be detected between 100- and 800-days post-vaccination, albeit based on a subset of only eleven samples. Id. at 638. McMahon’s findings were deemed consistent with the understood persistence of a wild virus measles infection, and its authors also noted the significance of the fact that the vaccine component RNA was specifically identified in the respiratory tract of the studied patients (underscoring the degree to which lymphoid tissue—to which a natural infection would spread as immune cells encountered the virus—was a likely situs for the virus to remain in the body). McMahon at 643. But its authors in no way implicated the vaccine as dangerous or pathologic in connection with its immune persistence (except in the limited circumstance of a person known to be immunodeficient or receiving immunosuppressive treatments). Id. Indeed, McMahon’s authors expressly observed that the vaccine remained safe and highly important in the prevention of measles, and that the exceedingly small sample size relied upon for its findings prevented drawing larger conclusions from the study. Id. at 644. Dr. Gish relied in part on McMahon for the contention that persistence of the measles virus in Petitioner could have later contributed to her development of chronic liver inflammation. Tr. at 50; First Gish Rep. at 24. But McMahon certainly does not equate persistence with pathogenicity— active or potential. Indeed, as Dr. MacGinnitie observed, McMahon did not show that the studied children actually had an infection in their liver—the measles vaccine virus RNA was only present in their respiratory secretions. Tr. at 176. And although the eleven samples had more often than not presented pre-detection with some infectious-like symptoms, McMahon’s authors noted that they could not confirm whether other, concurrent viral infections were not explanatory—and even more importantly, that “detection of [vaccine component measles RNA] alone does not allow for any assessment of whether infectious virus is present.” McMahon at 644. 7. P. Berry & G. Smith-Laing, Hepatitis A Vaccine Associated with Autoimmune Hepatitis, 13 World J. of Gastroenterology 2238-39 (2007), filed as Ex. 23 (ECF No. 18-8) (“Berry”). Berry is a case report in which a 56-year-old man developed acute liver injury consistent with autoimmune hepatitis ten days after he received the hepatitis A vaccine. Berry at 2238. Notably, the patient in Berry had also been diagnosed with acute hepatitis five months before the administration of the vaccine. Id. This case is thus distinguishable from Petitioner’s case, involving not only an entirely different vaccine—the hepatitis A vaccine—but a patient who had experienced a relapse of hepatitis post-vaccination. 19 8. Veerappan Veerappan is another case study offered for the general proposition that autoimmune hepatitis is associated with vaccination. First Gish Rep. at 16. In Veerappan, a 35-year-old male developed severe flu-like symptoms one week after receiving multiple vaccinations—typhoid, hepatitis A, oral polio, diphtheria/tetanus, and MMR. Veerappan at 212. A liver biopsy performed one month after initial presentation showed severe chronic hepatitis, which was deemed to be consistent with AIH. Id. The authors concluded that AIH may be a complication in patients who receive multiple vaccinations simultaneously. Id. at 213. But Veerappan’s authors provide no explanation for the significance of the receipt of so many vaccines at once, deeming them “a novel inciting event” worthy of consideration (but not shown to be likely pathogenic). Id. And Petitioner’s onset was not nearly so quick in this case. 9. Subramanian Subramanian is yet another, facially-inapposite case report. Here, a 45 year-old woman who had been diagnosed with a hepatitis A infection was hospitalized a month later, and her presenting symptoms and lab work were later deemed consistent with AIH. Subramanian at 1–2. Thus, the studied individual had not received any vaccine at all (let alone the MMR or Tdap vaccines), and was suspected to have developed AIH from her prior hepatitis infection (evidence of which was detected after her disease onset and which “remained positive” during her treatment. Id. at 2. Petitioner nevertheless (as noted above) relied on Subramanian, with Dr. Gish maintaining that it stood as evidence of the genetic susceptibility for AIH. Tr. at 69. But as noted above, Dr. Gish’s primary interest in Subramanian arises from its reference to an unfiled article (Vento) in which two relatives developed autoimmune hepatitis within five months of an acute hepatitis infection. Subramanian at 2 n.4. The authors concluded that a genetic disposition (specifically, a type of T cell defect) made the patients susceptible to AIH following the impact of infection. Id. In Dr. Gish’s view, Petitioner similarly likely suffered some kind of “T cell defect” due to genetic susceptibility, like the patients in Vento, but triggered here by a different acute immunologic stimulus. Id. at 69. But Dr. Gish later admitted that no genetic testing had been performed that would corroborate Petitioner’s susceptibility. Id. at 96. And Subramanian itself does not suggest that exposure to a measles wild virus or vaccine component could have the same impact on a genetically susceptible individual as a hepatitis A infection. 10. van Gemeren van Gemeren discusses two women in their 20s who developed AIH after receiving various vaccines. van Gemeren at 18–19. One developed AIH a month after receiving vaccines against hepatitis A and hepatitis B. Id. at 18. The other developed AIH ten days after she was vaccinated 20 against hepatitis A, diphtheria, whooping cough, and tetanus. Id. at 19. The article suggested that vaccination, especially vaccination against hepatitis A, may trigger AIH in genetically susceptible individuals. Id. at 21–22. However, van Gemeren acknowledges that no conclusive evidence has been found for a causal association between vaccines and the occurrence of autoimmune diseases. Id. at 21. Otherwise, this case report does not involve the MMR vaccine (the focus of Petitioner’s causation theory), does not discuss the impact of the tetanus-containing vaccine to any significant degree, and does a better job underscoring the possible impact of hepatitis-oriented vaccines. 11. Perumalswami The Perumalswami case report discussed a 31-year-old woman who developed autoimmune hepatitis 11 days after receiving hepatitis A and yellow fever vaccines. Perumalswami at 331. After vaccination and prior to developing symptoms, she had traveled to Nigeria for five days. Id. Perumalswami’s authors raised the possibility that these two vaccines may have been a triggering agent for AIH (but admitted that this was a novel finding). Id. at 333. Like the other case reports discussed above, however, this article says less about the potential pathogenicity of the vaccines at issue than it does about the risks of a hepatitis vaccine. 12. Sasaki Sasaki is the final case report offered by Petitioner to substantiate a vaccine-AIH relationship. In Sasaki, two female patients presented with AIH within one week and one month, respectively, after receiving the flu vaccine. Sasaki at 1–2. The authors admitted that a causal link could not be established, but hypothesized that the flu vaccine could trigger the development of AIH, given the possible link between immunization and other autoimmune diseases. Id. at 3. But as Dr. MacGinnitie pointed out, flu vaccine administration is so widespread that it is very likely that the development of AIH after vaccination in these cases was mere coincidence. Tr. at 155. And yet again—Sasaki, like prior case reports, does not involve the relevant vaccines in this case. 13. D. Robertson et al., Persistent Measles Virus Genome in Autoimmune Chronic Active Hepatitis, 330 The Lancet 9-11 (1987), filed as Ex. 29 (ECF No. 19-5) (“Robertson”). Robertson, a study from 1987, involves the measles virus and its putative association with “chronic active hepatitis.” Robertson at 9. 12 out of 18 studied patients with confirmed autoimmune chronic active hepatitis were found also to possess the measles virus genes. Id. at 10. Robertson’s authors concluded that the presence of high-titer antibodies to the measles virus in patients with AIH “suggests that these particular viruses may have a causal role in the condition.” Id. They also surmised that the patients’ exposure to measles resulted in a persistent incomplete infection occurring as a result of continued production of measles antigen and ineffective elimination of the virus. Id. at 11. 21 The Robertson study briefly mentions the measles vaccine but does not offer a potential causal mechanism, and suggests even that the measles vaccine might have prevented some instances of measles-caused AIH (resulting in onset only in older cohorts). Robertson at 10. In addition (and as noted in my discussion of Christen above), there is reason to doubt whether the defined group of individuals with “autoimmune chronic active hepatitis” would be suffering from what is currently understood to be AIH. Otherwise, Robertson’s authors admitted that the finding of persistent measles virus in the small set of subjects could simply be attributable to an “epiphenomenon” 14—meaning a secondary effect arising from, but not causal of, a primary process (and thus not causal of the studied, hepatitis-like illness). 14. G. Mieli-Vergani et al., Measles and Autoimmune Chronic Active Hepatitis, 334 The Lancet 688 (1989), filed as Ex. 30 (ECF No. 19-6) (“Mieli-Vergani I”). Petitioner deemed Mieli-Vergani I to substantiate an association between the measles vaccine and AIH. Mieli-Vergani I’s authors (in a single-paragraph summary 15 published in the Lancet) mentioned a study observing that 8 out of 12 children with autoimmune hepatitis had received the measles vaccination and had tested positive for low titers of measles antibody. Mieli- Vergani I at 688. The authors surmised that there could be a causal link between measles and autoimmune hepatitis, at least in childhood. Id; First Gish Rep. at 19. But the cursory discussion of these findings prevents any greater scrutiny of their reasonableness. And as noted expressly in Christen—published 30 years later, and thus with the benefit of further study (as well as perhaps a full copy of the article)—Mieli-Vergani I did not find the existence of the measles antibody titers significant, when comparing sick individuals with a control, healthy population—thereby reducing the evidentiary value of this somewhat-stale article. Christen at 43. 15. Nanan Nanan’s authors sought to investigate the impact of measles infection-induced immune suppression (which has also been observed to a lesser extent in vaccination) by seeking to analyze T cells extracted from serum of four pediatric subjects with measles infections, plus four older individuals who had received the measles vaccine. Nanan at 202. In particular, it sought to observe the expression of leukocyte function-associated antigen 1 (LFA-1)—a cell surface protein found on human T cells, and deemed important to a functioning immune process. Id. at 201–02. 14 “Epiphenomenon” is defined as “an accessory, exceptional, or accidental occurrence in the course of an attack of any disease.” Epiphenomenon, Dorland’s Medical Dictionary Online, https://www.dorlandsonline.com/dorland/definition?id=16902&searchterm=epiphenomenon (last visited on May 27, 2025). 15 Petitioner has not filed a full version of Mieli-Vergani I. 22 Nanan found that there was a “remarkable loss” of LFA-1-bright cells during natural measles infection, and after measles vaccination. Nanan at 204–05. The findings suggested to the authors that sequestration of T cells is a feature of the measles virus infection and vaccination. Id. at 209. This is problematic, since the integration and control of immune responses depend on regulated trafficking of lymphocytes. Id. The disruption of lymphocyte trafficking by random distribution of T cells in all areas of lymphoid organs could impair host defenses and result in immune suppression. Id. Petitioner cited Nanan to support her contention that the measles component of the MMR vaccine could initiate immune dysfunction, leading in some form to an autoimmune response (although Nanan itself does not discuss such secondary disease in the context of measles-induced immunosuppression). Tr. at 40–41; First Gish Rep. at 19. While Dr. Gish admitted that there is no evidence in this case that Petitioner likely ever suffered from a prolonged measles vaccine-induced suppression, he contended that this was not necessary to meet Petitioner’s burden of proof on causation. Tr. at 45–46. And it was likely in any event that immune activation persisted even if Petitioner’s system had cleared measles post-vaccination. Id. at 49. In response, Dr. MacGinnitie emphasized that the authors of Nanan did not provide evidence that the observed decrease of LFA- 1 was clinically meaningful, nor did they offer evidence that the small group of patients they considered had experienced any actual immune suppression sufficient to cause disease. Tr. at 163. There is no reason to doubt the validity of Nanan’s specific findings, and I deem its methodology reliable. Indeed, its findings are consistent with the already-understood immunosuppressive impact of the wild measles virus. But Nanan cannot be read to support the conclusion that receipt of a measles-containing vaccine is likely pathologic for this same reason – or that AIH is more likely in the context of a prior measles vaccination. It thus stands as somewhat weak evidence overall for the contention that the MMR vaccine has the capability to produce disease-encouraging immune suppression. 16. Munyer Munyer is a 1975 study that sought to consider the impact of receipt of the version of MMR vaccine used at the time on T cell responses in the blood of children. Sera was drawn from an unspecified number of vaccinated children (pre and post-vaccination), then stimulated ex vivo. Munyer at 75–76. An impairment in lymphocyte response to stimulation with antigen was observed in the vaccinated samples (via an in vitro test), with the impairment lasting for one to five weeks post-vaccination. Id. at 77. From this, Munyer’s authors concluded that the MMR vaccine could cause a depression of lymphocyte function - although the degree of impairment was deemed likely more pronounced for an active infection than vaccination. Id. at 77–78. Munyer also, however, noted the following: 23 no significant alteration was observed in the absolute number of lymphocytes in the peripheral blood of vaccinated subjects, either in comparison with base line (before vaccination) counts or with counts from a group of unvaccinated controls. Similarly, no decrease in either the percentage or the absolute number of peripheral blood T-lymphocytes was observed after vaccination. Munyer at 76. Thus, although experimental stimulation of blood samples revealed an impairment in immune cells, actual, in vivo vaccination did not. It is the results of the latter that are ultimately in contention in this case. Petitioner cites Munyer for the same reason as Nanan—to support her argument that the measles vaccine could have induced immunosuppression in Petitioner, leading to the development of AIH. First Gish Rep. at 19. Dr. MacGinnitie criticized this article during his testimony, however, noting that it was 50 years old (and hence outdated), and claiming that its authors used “rather primitive techniques.” Tr. at 163. More importantly, however, Dr. MacGinnitie observed that Munyer did not provide evidence that the immunosuppression observed was meaningful from a clinical standpoint (as opposed simply to an observed, absolute phenomena). Id. The above- referenced block quote citation from the article directly corroborates this opinion. My reaction to Munyer is consistent with my reading of Nanan. While Munyer’s findings may narrowly be based on a methodologically-reliable experiment, the article stands only as a single (and facially-outdated) “brick” in the causation theory “wall” Petitioner seeks to build— and it does not itself establish vaccine-related pathology. Rather, it constitutes additional evidence that the measles component of the MMR vaccine may cause an experimentally-observable amount of immune suppression—but whether that is of a magnitude sufficient to result in an autoimmune disease is not addressed. And it cannot be concluded from Munyer that the vaccine when actually administered in vivo does cause observable immune suppression, and/or has pathologic outcomes. Munyer’s own findings suggest the opposite. 17. Rennick Rennick noted that despite the widespread use of measles vaccines, “little is known about the attenuation profile of the vaccine virus or what cells it targets upon vaccination.” Rennick at 2197. Accordingly, Rennick’s authors sought to compare the immunogenicity of the vaccine compared to its biologic viral parent, specifically by looking to identify the vaccine’s antigenic targets after administration by injection. Id. The study (using animal subjects) determined that infected cells after vaccination are predominantly macrophages and dendritic cells in subcutaneous tissues, found abundantly at the site of injection (rather than muscle cells). Id. at 2199. 24 Petitioner has cited Rennick as establishing that the measles vaccine virus strain likely infected Petitioner’s immune cells. Tr. at 38. But the means by which the immune system takes up the vaccine does not also lead to the conclusion that pathology was an expected, or even possible, outcome due to vaccination. And Rennick says other things about the impact of a measles infection that are inconsistent with Petitioner’s theory. For example, Rennick notes that the measles wild virus has a much shorter, preclinical latency period after infection (10 to 14 days) than what is proposed in this case, undermining Petitioner’s general argument that once vaccinated, pathology remains possible months later. Rennick at 2192. Rennick also underscores the principal danger of a wild measles infection—the increase in “susceptibility to opportunistic infections”—in addition to direct risk from the infection itself (and here, the evidence that Petitioner’s AIH is attributable to an opportunistic hepatitis infection is wholly lacking). 18. da Silva Antunes da Silva Antunes constitutes one of the few articles offered in this case to link the Tdap vaccine to Petitioner’s injury. Its authors sought mainly to better understand the effects of the transition from the use of whole cell pertussis-containing vaccines to the acellular form (which in the U.S. replaced whole cell pertussis, due to concerns that the former version was associated with adverse events). da Silva Antunes at 3856. Accordingly (and in the wake of evidence that pertussis disease was increasing even in places where the acellular form was used), da Silva Antunes’s authors attempted to compare the immune responses of children who received whole cell pertussis originally versus those who first received the acellular form, comparing both groups after they received an acellular pertussis booster. Id. at 3855. The study revealed that subjects who had been previously vaccinated with whole cell pertussis produced more of a specific form of T helper cell (Th17 cells). Id. at 3856–58. In effect, despite the adverse events associated with the largely- discontinued whole cell pertussis, receipt of that form of the vaccine was deemed to impart greater immunity overall. Id. at 3869–70. Petitioner cited da Silva Antunes to show how an increase in Th17 cells could lead to autoimmune hepatitis. Tr. at 169–70. Dr. Gish reasoned that Th17 cells are critical to regulate both protective and pathogenic immune responses. First Gish Rep. at 22. Because Petitioner was likely administered the whole cell pertussis vaccine as a child, she would produce more Th17 cells after she received the Tdap booster vaccine. Id. Dr. MacGinnitie argued in response, however, that Dr. Gish had never explained how the production of Th17 cells would actually result in AIH (specifically by causing damage to cells in the liver). Tr. at 173. And Petitioner’s Th17 levels were never tested, so there was no way to know if they were elevated at all. Id. As with other items of literature filed by Petitioner in this case, there is no reason to doubt the validity of da Silva Antunes’s findings. But the article does not seek to evaluate vaccine pathology, but instead to measure vaccine effectiveness. And the fact that it suggests that the Tdap vaccine can cause an increase of a certain kind of immune cell does not mean that the ordinary 25 receipt of the vaccine is likely to cause that immune cell to proliferate so much that it becomes the driver of a pathologic autoimmune process. 19. Lafdil Lafdil appears to have been offered to link the findings from da Silva Antunes discussed above to Petitioner’s theory in this case. Lafdil is a review article discussing other studies that have observed the role that Th17 T-helper cells play in the development of autoimmune liver disease. Lafdil at 250. It defines Th17 cells to be “a subset of T helper cells that play important roles in host defense against extracellular bacteria as well as in the pathogenesis of autoimmune disease.” Id. Studies show that IL-17 is significantly elevated in a variety of chronic liver diseases, and Lafdil specifically discusses (a) a laboratory animal model form of hepatitis driven by T cells, (b) alcoholic liver disease, (c) chronic hepatitis B and C viral-induced liver infections, and (d) autoimmune liver disease. Id. at 251–52. The latter category arguably relates to AIH (although that term is not used in the section discussing autoimmune liver disease), but Lafdil refers mainly to studies showing increased levels of a T helper cell-associated cytokine in studies involving cirrhosis 16—which Ms. Exum does not have—and otherwise the authors only say that the mechanisms for why these T helper cells increase in this context are unknown, along with their role in aiding pathogenesis of disease. Id. at 252. 20. I. Amanna et al., Duration of Humoral Immunity to Common Viral and Vaccine Antigens, 357 N. Eng. J. Med. 1903-15 (2007), filed as Ex. 36 (ECF No. 20-3) (“Amanna”) Amanna sought to evaluate “the issue of antibody maintenance after infection or vaccination,” by reviewing 630 serum samples drawn from 45 subjects, and where the blood serum samples had been drawn regularly and “banked” over an average period of 15 years. Amanna at 1905. The study’s authors looked to evaluate the temporal length of antibody maintenance (and whether the antibodies were at protective levels to fight off future disease) for a number of infections, including most of the viruses that the vaccines Petitioner received were aimed against (such as the MMR components). Id. at 1906). Amanna’s authors determined that the antibody responses to a live viral infection were generally longer than to responses to the kind of nonreplicating protein antigens often contained in vaccines. Id. at 1911. But even exposure to the latter conferred some long-term benefit; the authors specifically found a comparatively-rapid decrease in tetanus-specific antibodies over a more than ten-year period. Id. at 1908. Dr. Gish generally relied upon Amanna to support his contentions about the medically- acceptable timeframe in which Petitioner’s post-vaccination AIH began, although he did not 16 Cirrhosis is a condition in which an individual’s liver is found to be scarred and permanently damaged, due to alcoholism or some other disease process. Cirrhosis, National Institute of Diabetes and Digestive and Kidney Diseases, https://www.niddk.nih.gov/health-information/liver-disease/cirrhosis#:~:text=Print%20All%20Sections- ,Definition%20%26%20Facts,your%20liver%20begins%20to%20fail. (last visited on May 27, 2025). 26 explain in detail how it supported his contentions (which seemed more to embrace the idea that the Tdap booster caused a faster immune response due to Petitioner’s prior receipt of the whole cell pertussis form of vaccine). First Gish Rep. at 23. 21. Schonberger Schonberger is an epidemiologic study performed after the 1970s swine flu epidemic, and considers the impact of the immunization program initiated by the federal government in response. The study evaluated over 1,000 individuals who had experienced Guillain-Barré syndrome (“GBS”) in the 1976–77 timeframe, comparing those who received the version of the vaccine used at that time (now nearly fifty years ago) versus those who did not, and finding that the incidence rate for GBS was higher among those who had received the vaccine. Schonberger at 109. Schonberger also made findings about the post-vaccination timeframe in which individuals developed GBS, peaking within two to three weeks but significantly declining after ten. Id. at 112. Schonberger is consistently cited in the Program by virtually any claimant seeking to establish how the flu vaccine could cause a demyelinating autoimmune disease of the peripheral or central nervous system. Hence, it has no direct relevance to this case, which involves different vaccines and a different injury. Schonberger is also commonly invoked to support arguments about what constitutes a reasonable post-vaccination timeframe for development of an antibody-driven autoimmune disease - and here, Dr. Gish contended that it supported the conclusion that there was risk of a possible autoimmune, post-vaccination injury up to ten weeks after. Second Gish Rep. at 10. 22. Excerpts, Institute of Medicine, Adverse Effects of Vaccines: Evidence and Causality, 556- 62 (Kathleen Stratton, Andrew Ford, Erin Rusch & Ellen W. Clayton, eds., 2012), filed as Ex. 45 (ECF No. 45-3) (“2012 IOM Rep.”) The 2012 IOM Report is a book-length evaluation of different risks associated with a variety of commonly-administered vaccines. Petitioner has offered a collection of excerpts from it, highlighting a few points: (a) that evaluating a potential adverse effect of vaccination involves consideration both of what the underlying natural infection does as well as the adverse event’s known pathophysiology (2012 IOM Rep. at 40); (b) what the committee did in evaluating the adequacy of evidence of a particular outcome (Id. at 12–13); (c) that no studies (as of 2012) were considered in assessing the risk of hepatitis due to the MMR vaccine (Id. at 211); and (d) that case studies have associated the MMR vaccines with hepatitis, but that the mechanistic evidence of an association (whether with respect to the MMR or hepatitis A vaccine) is weak, given what is known about the natural infection (Id. at 212, 429–30). 27 B. Respondent’s Literature 17 1. G. Mieli-Vergani et al., Autoimmune Hepatitis, 4:18017 Nat. Rev. Dis. Primers 1-21 (2018), filed as Ex. A Tab 2 (ECF No. 25-2) (“Mieli-Vergani II”) The primary author of this review article is the same as Mieli-Vergani I, cited by Petitioner. Mieli-Vergani II notes some basic facts about AIH, largely consistent with Mack. However, it also makes observations about AIH that are somewhat contrary to what Petitioner gleaned from Mieli- Vergani I. In particular, Mieli-Vergani II deems the cause of AIH to be unknown (Mieli-Vergani II at 10), and in discussing potential mechanisms for its pathogenesis, like molecular mimicry, it makes no mention of measles virus (as Christen noted Mieli-Vergani I had done), focusing instead on case reports involving hepatitis infections (Id. at 4). But Mieli-Vergani II does propose a role for T helper cells in propagating disease, as well as the loss of immune tolerance—both of which Petitioner relies upon in her causation theory. 2. Beretta-Piccoli Beretta-Piccoli is a case report showing the counter-risk posed by anti-malarial medicine in causing AIH. It discusses a 65-year-old woman who made yearly visits to Tanzania, and took an anti-malarial drug, Malarone (atovaquone/proguanil), on each trip. Beretta-Piccoli at 293–94. The year before the illness at issue, she had become jaundiced with an acute hepatitis following her trip, and her illness was thought to be drug-induced liver injury due to an antibiotic (although she had also been taking Malarone), although it resolved in two weeks. Id. at 294, 296. The following year, she returned to Tanzania and again took Malarone. Id. at 294. Shortly after she returned, she went to the hospital with fatigue, jaundice, and dark urine. Id. at 293. She reported that she had stopped taking Malarone four days earlier due to the appearance of jaundice. Id. at 294. After performing a liver biopsy and several lab tests, doctors tentatively diagnosed the patient with AIH. Id. at 295. The patient’s liver inflammation took a long time to resolve, allowing a firm diagnosis only three years after presentation. Id. at 297. Beretta-Piccoli’s authors concluded that the anti-malarial medication was the likely cause of the patient’s liver pathology, but they acknowledged that a second case would be needed to confirm “the rare but potentially severe hepatotoxicity of this commonly used antimalarial prophylaxis/treatment.” Id. at 296–97. Respondent cited Beretta-Piccoli as evidence that anti-malarial medication can cause AIH. Crippin Rep. at 4–5. And there are similarities between this patient and Ms. Exum. Both traveled to Tanzania, and both needed prolonged therapy with corticosteroids/prednisone after falling ill. However, there are also significant factual differences. The patient in Beretta-Piccoli developed 17 Respondent offered 38 items of literature. Exhibit List, filed January 24, 2024 (ECF No. 49). But Respondent does not bear the burden of proof in this matter, and therefore it is far less critical from a fairness standpoint that I unpack each item of literature he filed. I instead review herein only those items filed by Respondent that are most important to my analysis. 28 very clear signs of liver injury (jaundice, dark urine) while she was actively taking the anti-malarial medication, but Petitioner did not develop symptoms (other than fatigue) in such a short timeframe. 3. 2012 IOM Report 18 Respondent also referenced portions of the 2012 IOM Report, in support of his contention that Petitioner had not presented sufficient evidence to support a molecular mimicry mechanism. Tr. at 184. The relevant excerpts of the 2012 IOM Report confirm that proof of homology (between different amino acid sequences in a foreign antigen and self protein structure) is insufficient to prove a molecular mimicry reaction. See 2012 IOM Report at 60 (deeming it “problematic” to prove autoimmunity due to molecular mimicry, and noting that homology is common in nature and usually not pathogenic). Yet Dr. Gish did not even attempt to demonstrate homology in the first place. Additionally, the 2012 IOM Report notes that pathogenic molecular mimicry may serve as a causal explanation for an autoimmune disease if the theory is corroborated with evidence of an autoimmune attack in vivo, evidenced by proof of “local binding of antibody with activation of the complement cascade, activation of the appropriate co-stimulatory T cells signals and cytokines, and/or involvement of other pathogenic effector mechanisms in a biologically relevant tissue site.” 2012 IOM Report at 71. Thus, Dr. MacGinnitie contended, Petitioner would need to show that there were antibodies or T cells that cross-reacted in her case with vaccine components, and that they were actually present in vivo. Tr. at 185. Furthermore, Petitioner would have to show that these immune cells were actually capable of mediating organ damage. Id. But no such evidence existed in this matter. 4. Mina Mina is a review article discussing the significantly positive impact of receipt of the measles vaccine worldwide. See Mina at S11. It notes that “[m]easles immune suppression is an invisible hallmark of measles infection, predisposing to secondary infections, the major cause of measles associated mortality.” Mina at S13. But “[m]easles vaccination programs have been among the greatest public health achievements” in eliminating the measles infection across the globe. Id. at S10. This is attributed to “direct heterologous benefits of the measles vaccines that enhance innate and adaptive immune responses.” Id. Receipt of the measles vaccine thus not only prevents directly a subsequent measles infection, but reduces the likelihood of experiencing some secondary, opportunistic infection or illness (since the immunosuppression caused by an initial measles infection is eliminated). Id. at S13–15. The measles infection can have a longer-term impact on the immune system—what Mina terms “measles virus associated immune-amnesia.” Id. at S14. 18 See Ex. C Tab 2 (ECF No. 26-2)—the portions filed by Respondent are different than what Petitioner highlighted. 29 Respondent cited Mina to refute Petitioner’s argument that the measles vaccine is capable of suppressing the immune system to any comparable pathologic degree. Tr. at 164; MacGinnitie Rep. at 8–9. As Dr. MacGinnitie explained, the measles vaccine in fact prevents the profound immune suppression caused by the measles virus (precisely what Petitioner argues in part caused her to experience AIH). Tr. at 165. 5. AC of Pediatrics AC of Pediatrics is an annually-updated clinical manual relied upon by treaters. It acknowledges the immune-suppressive nature of the wild measles, but not the vaccine. It specifically notes that “children who have had measles have long-term blunted immune responses to other pathogens and increased mortality attributable to the known effects of the measles virus on lymphocytes.” AC of Pediatrics at 503. It then discusses the importance of measles prevention (i.e. by receiving the measles vaccine). Id. at 503–04. Like Mina, AC of Pediatrics was cited to refute Petitioner’s argument that the measles vaccine can cause clinically meaningful immune suppression, in comparison to the known impact of the underlying wild virus. Tr. at 165–66. 6. T. Safranek et al., Reassessment of the Association between Guillain-Barre Syndrome and Receipt of Swine Influenza Vaccine in 1976-1977: Results of a Two-State Study, 133 Am. J. of Epidemiology 940-51 (1991), filed as Ex. C-19 (ECF No. 26-19) (“Safranek”). Safranek, which involved the swine flu vaccine and GBS, found that there was an increased risk of developing GBS within six weeks of vaccination, with no increased risk after. Safranek at 940. Respondent cited Safranek to support his argument that the onset of autoimmune diseases (if vaccine-related) typically occurs no more than six weeks of vaccination (rather than up to five months, as Petitioner contended); Tr. at 176 (Dr. MacGinnitie deeming six weeks “the outer limit” for a vaccine-triggered autoimmune injury). IV. Procedural History As noted above, the case was initiated in 2021. Respondent filed his Rule 4(c) Report disputing Petitioner’s right to compensation on August 19, 2022. Expert reports were filed through the end of 2022, and the trial was held in March 2024. I initially denied entitlement on August 29, 2024. On September 30, 2024, Petitioner filed a motion for review. The Court granted the motion in part, and remanded the case on February 26, 2025, with instructions to elaborate on my rational for my conclusions. In particular, the Court has directed the following: - “provide a rationale for crediting or discrediting the medical literature filed in this case; such a rationale supporting any conclusions here is necessary to 30 confirm that the prong one 19 legal standard was correctly applied,” in order to “sufficiently articulate the legal, factual, and evidentiary bases” for my conclusion that the first prong for causation was not met (Remand Order at 43– 44); - “provide a more fulsome explanation . . . regarding (1) the probative weight of the medical literature Petitioner cited, including Petitioner’s case reports involving relevant vaccines and vaccine antigens, (2) his rationale for accepting or rejecting that evidence; and, as necessary, (3) the extent to which he is crediting each expert’s testimony; and (4) his rationale for doing so” (Remand Order at 44); - “to the extent that, on remand, . . . analysis of prong one affects [my] findings pertaining to Petitioner’s prong two logical sequence of cause and effect, [I] should revise and explain those findings accordingly” (Remand Order at 47); and - “(1) revise [my] findings on prong two, only to the extent that [my] prong one analysis on remand affects those findings, (2) revise [my] analysis pertaining to alternative causes, insofar as [I] improperly required Petitioner to “persuasively limit or exclude all of them,” and, importantly, (3) fully describe [my] rationale for all of his prong two conclusions in the remand decision” (Remand Order at 50–51). V. Applicable Legal Standards A. Petitioner’s Overall Burden in Vaccine Program Cases To receive compensation in the Vaccine Program, a petitioner must prove either: (1) that he suffered a “Table Injury”—i.e., an injury falling within the Vaccine Injury Table— corresponding to one of the vaccinations in question within a statutorily prescribed period of time or, in the alternative, (2) that his illnesses were actually caused by a vaccine (a “Non-Table Injury”). See Sections 13(a)(1)(A), 11(c)(1), and 14(a), as amended by 42 C.F.R. § 100.3; § 11(c)(1)(C)(ii)(I); see also Moberly v. Sec’y of Health & Hum. Servs., 592 F.3d 1315, 1321 (Fed. Cir. 2010); Capizzano v. Sec’y of Health & Hum. Servs., 440 F.3d 1317, 1320 (Fed. Cir. 2006). 20 There is no Table injury for AIH, so Petitioner can only assert a causation-in-fact claim. 19 Prong references are to the Federal Circuit’s decision that established the causation standard applied in Vaccine Program cases—Althen v. Sec'y of Health and Hum. Servs., 418 F.3d 1274, 1278 (Fed. Cir. 2005). 20 Decisions of special masters (some of which I reference in this ruling) constitute persuasive but not binding authority. Hanlon v. Sec’y of Health & Hum. Servs., 40 Fed. Cl. 625, 630 (1998). By contrast, Federal Circuit rulings concerning legal issues are binding on special masters. Guillory v. Sec’y of Health & Hum. Servs., 59 Fed. Cl. 121, 31 For both Table and Non-Table claims, Vaccine Program petitioners bear a “preponderance of the evidence” burden of proof. Section 13(1)(a). That is, a petitioner must offer evidence that leads the “trier of fact to believe that the existence of a fact is more probable than its nonexistence before [he] may find in favor of the party who has the burden to persuade the judge of the fact’s existence.” Moberly, 592 F.3d at 1322 n.2; see also Snowbank Enter. v. United States, 6 Cl. Ct. 476, 486 (1984) (mere conjecture or speculation is insufficient under a preponderance standard). Proof of medical certainty is not required. Bunting v. Sec’y of Health & Hum. Servs., 931 F.2d 867, 873 (Fed. Cir. 1991). In particular, a petitioner must demonstrate that the vaccine was “not only [the] but-for cause of the injury but also a substantial factor in bringing about the injury.” Moberly, 592 F.3d at 1321 (quoting Shyface v. Sec’y of Health & Hum. Servs., 165 F.3d 1344, 1352–53 (Fed. Cir. 1999)); Pafford v. Sec’y of Health & Hum. Servs., 451 F.3d 1352, 1355 (Fed. Cir. 2006). A petitioner may not receive a Vaccine Program award based solely on his assertions; rather, the petition must be supported by either medical records or by the opinion of a competent physician. Section 13(a)(1). In attempting to establish entitlement to a Vaccine Program award of compensation for a Non-Table claim, a petitioner must satisfy all three of the elements established by the Federal Circuit in Althen v. Sec'y of Health and Hum. Servs., 418 F.3d 1274, 1278 (Fed. Cir. 2005): “(1) a medical theory causally connecting the vaccination and the injury; (2) a logical sequence of cause and effect showing that the vaccination was the reason for the injury; and (3) a showing of proximate temporal relationship between vaccination and injury.” Each Althen prong requires a different showing. Under Althen prong one, petitioners must provide a “reputable medical theory,” demonstrating that the vaccine received can cause the type of injury alleged. Pafford, 451 F.3d at 1355–56 (citations omitted). To satisfy this prong, a petitioner’s theory must be based on a “sound and reliable medical or scientific explanation.” Knudsen v. Sec’y of Health & Hum. Servs., 35 F.3d 543, 548 (Fed. Cir. 1994). Such a theory must only be “legally probable, not medically or scientifically certain.” Id. at 549. Petitioners may satisfy the first Althen prong without resort to medical literature, epidemiological studies, demonstration of a specific mechanism, or a generally accepted medical theory. Andreu v. Sec’y of Health & Hum. Servs., 569 F.3d 1367, 1378–79 (Fed. Cir. 2009) (citing Capizzano, 440 F.3d at 1325–26). Special masters, despite their expertise, are not empowered by statute to conclusively resolve what are essentially thorny scientific and medical questions, and thus scientific evidence offered to establish Althen prong one is viewed “not through the lens of the laboratorian, but instead from the vantage point of the Vaccine Act’s preponderant evidence standard.” Id. at 1380. Distinguishing between “preponderant evidence” and “medical certainty” is important because special masters must take care not to impose an evidentiary burden that is too 124 (2003), aff’d 104 F. App’x. 712 (Fed. Cir. 2004); see also Spooner v. Sec’y of Health & Hum. Servs., No. 13- 159V, 2014 WL 504728, at *7 n.12 (Fed. Cl. Spec. Mstr. Jan. 16, 2014). 32 high. Bunting v. Sec'y of Health & Human Servs., 931 F.2d 867, 873 (Fed.Cir.1991) (“The standard of proof required by the [Vaccine] Act is simple preponderance of evidence; not scientific certainty.... [I]t is not plaintiff's burden to disprove every possible ground of causation suggested by defendant nor must the findings of the court meet the standards of the laboratorian.”) (citations and internal quotation marks omitted). In discussing the evidentiary standard applicable to the first Althen prong, the Federal Circuit has consistently rejected the contention that it can be satisfied merely by establishing the proposed causal theory’s scientific or medical plausibility. See Kalajdzic v. Sec’y of Health & Hum. Servs., No. 2023-1321, 2024 WL 3064398, at *2 (Fed. Cir. June 20, 2024) (arguments “for a less than preponderance standard” deemed “plainly inconsistent with our precedent” (citing Moberly, 592 F.3d at 1322)); Boatmon v. Sec’y of Health & Hum. Servs., 941 F.3d 1351, 1359 (Fed. Cir. 2019); see also Demore v. Sec'y of Health & Hum. Servs., No. 20-1265V, 2024 WL 4542934 (Fed. Cl. Spec. Mstr. Sept. 26, 2024), aff'd, No. 20-1265V, 2025 WL 868902, at *4 (Fed. Cl. Mar. 20, 2025) (rejecting the argument that a petitioner’s burden is to prove that a causation theory is plausible and instead requiring petitioner to prove the theory by a preponderance of the evidence) (emphasis added). And petitioners always have the ultimate burden of establishing their overall Vaccine Act claim with preponderant evidence. W.C. v. Sec’y of Health & Hum. Servs., 704 F.3d 1352, 1356 (Fed. Cir. 2013) (citations omitted); Tarsell v. United States, 133 Fed. Cl. 782, 793 (2017) (noting that Moberly “addresses the petitioner’s overall burden of proving causation-in-fact under the Vaccine Act” by a preponderance standard). The second Althen prong requires proof of a logical sequence of cause and effect, usually supported by facts derived from a petitioner’s medical records. Althen, 418 F.3d at 1278; Andreu, 569 F.3d at 1375–77; Capizzano, 440 F.3d at 1326; Grant v. Sec’y of Health & Hum. Servs., 956 F.2d 1144, 1148 (Fed. Cir. 1992). In establishing that a vaccine “did cause” injury, the opinions and views of the injured party’s treating physicians are entitled to some weight. Andreu, 569 F.3d at 1367; Capizzano, 440 F.3d at 1326 (“medical records and medical opinion testimony are favored in vaccine cases, as treating physicians are likely to be in the best position to determine whether a ‘logical sequence of cause and effect show[s] that the vaccination was the reason for the injury’”) (quoting Althen, 418 F.3d at 1280). Medical records are generally viewed as particularly trustworthy evidence, since they are created contemporaneously with the treatment of the patient. Cucuras v. Sec’y of Health & Hum. Servs., 993 F.2d 1525, 1528 (Fed. Cir. 1993). Medical records and statements of a treating physician, however, do not per se bind the special master to adopt the conclusions of such an individual, even if they must be considered and carefully evaluated. Section 13(b)(1) (providing that “[a]ny such diagnosis, conclusion, judgment, test result, report, or summary shall not be binding on the special master or court”); Snyder v. Sec’y of Health & Hum. Servs., 88 Fed. Cl. 706, 746 n.67 (2009) (“Snyder II”) (“there is nothing . . . that mandates that the testimony of a treating physician is sacrosanct—that it must be accepted in 33 its entirety and cannot be rebutted”). As with expert testimony offered to establish a theory of causation, the opinions or diagnoses of treating physicians are only as trustworthy as the reasonableness of their suppositions or bases. The views of treating physicians should be weighed against other, contrary evidence also present in the record—including conflicting opinions among such individuals. Hibbard v. Sec’y of Health & Hum. Servs., 100 Fed. Cl. 742, 749 (2011) (not arbitrary or capricious for special master to weigh competing treating physicians’ conclusions against each other), aff’d, 698 F.3d 1355 (Fed. Cir. 2012); Veryzer v. Sec’y of Dept. of Health & Hum. Servs., No. 06-522V, 2011 WL 1935813, at *17 (Fed. Cl. Spec. Mstr. Apr. 29, 2011), mot. for review den’d, 100 Fed. Cl. 344, 356 (2011), aff’d without opinion, 475 F. Appx. 765 (Fed. Cir. 2012). The third Althen prong requires establishing a “proximate temporal relationship” between the vaccination and the injury alleged. Althen, 418 F.3d at 1281. That term has been equated to the phrase “medically-acceptable temporal relationship.” Id. A petitioner must offer “preponderant proof that the onset of symptoms occurred within a timeframe which, given the medical understanding of the disorder’s etiology, it is medically acceptable to infer causation.” de Bazan v. Sec’y of Health & Hum. Servs., 539 F.3d 1347, 1352 (Fed. Cir. 2008). The explanation for what is a medically acceptable timeframe must align with the theory of how the relevant vaccine can cause an injury (Althen prong one’s requirement). Id. at 1352; Shapiro v. Sec’y of Health & Hum. Servs., 101 Fed. Cl. 532, 542 (2011), recons. den’d after remand, 105 Fed. Cl. 353 (2012), aff’d mem., 503 F. Appx. 952 (Fed. Cir. 2013); Koehn v. Sec’y of Health & Hum. Servs., No. 11-355V, 2013 WL 3214877 (Fed. Cl. Spec. Mstr. May 30, 2013), mot. for rev. den’d (Fed. Cl. Dec. 3, 2013), aff’d, 773 F.3d 1239 (Fed. Cir. 2014). B. Legal Standards Governing Factual Determinations The process for making determinations in Vaccine Program cases regarding factual issues begins with consideration of the medical records. Section 11(c)(2). The special master is required to consider “all [ ] relevant medical and scientific evidence contained in the record,” including “any diagnosis, conclusion, medical judgment, or autopsy or coroner's report which is contained in the record regarding the nature, causation, and aggravation of the petitioner's illness, disability, injury, condition, or death,” as well as the “results of any diagnostic or evaluative test which are contained in the record and the summaries and conclusions.” Section 13(b)(1)(A). The special master is then required to weigh the evidence presented, including contemporaneous medical records and testimony. See Burns v. Sec'y of Health & Hum. Servs., 3 F.3d 415, 417 (Fed. Cir. 1993) (determining that it is within the special master's discretion to determine whether to afford greater weight to contemporaneous medical records than to other evidence, such as oral testimony surrounding the events in question that was given at a later date, provided that such determination is evidenced by a rational determination). 34 As noted by the Federal Circuit, “[m]edical records, in general, warrant consideration as trustworthy evidence.” Cucuras, 993 F.2d at 1528; Doe/70 v. Sec'y of Health & Hum. Servs., 95 Fed. Cl. 598, 608 (2010) (“[g]iven the inconsistencies between petitioner's testimony and his contemporaneous medical records, the special master's decision to rely on petitioner's medical records was rational and consistent with applicable law”), aff'd, Rickett v. Sec'y of Health & Hum. Servs., 468 F. App’x 952 (Fed. Cir. 2011) (non-precedential opinion). A series of linked propositions explains why such records deserve some weight: (i) sick people visit medical professionals; (ii) sick people attempt to honestly report their health problems to those professionals; and (iii) medical professionals record what they are told or observe when examining their patients in as accurate a manner as possible, so that they are aware of enough relevant facts to make appropriate treatment decisions. Sanchez v. Sec'y of Health & Hum. Servs., No. 11–685V, 2013 WL 1880825, at *2 (Fed. Cl. Spec. Mstr. Apr. 10, 2013); Cucuras v. Sec'y of Health & Hum. Servs., 26 Cl. Ct. 537, 543 (1992), aff'd, 993 F.2d at 1525 (Fed. Cir. 1993) (“[i]t strains reason to conclude that petitioners would fail to accurately report the onset of their daughter's symptoms”). Accordingly, if the medical records are clear, consistent, and complete, then they should be afforded substantial weight. Lowrie v. Sec'y of Health & Hum. Servs., No. 03–1585V, 2005 WL 6117475, at *20 (Fed. Cl. Spec. Mstr. Dec. 12, 2005). Indeed, contemporaneous medical records are often found to be deserving of greater evidentiary weight than oral testimony—especially where such testimony conflicts with the record evidence. Cucuras, 993 F.2d at 1528; see also Murphy v. Sec'y of Health & Hum. Servs., 23 Cl. Ct. 726, 733 (1991), aff'd per curiam, 968 F.2d 1226 (Fed. Cir. 1992), cert. den'd, Murphy v. Sullivan, 506 U.S. 974 (1992) (citing United States v. United States Gypsum Co., 333 U.S. 364, 396 (1947) (“[i]t has generally been held that oral testimony which is in conflict with contemporaneous documents is entitled to little evidentiary weight.”)). However, the Federal Circuit has also noted that there is no formal “presumption” that records are accurate or superior on their face to other forms of evidence. Kirby v. Sec’y of Health & Hum. Servs., 997 F.3d 1378, 1383 (Fed. Cir. 2021). There are certainly situations in which compelling oral or written testimony (provided in the form of an affidavit or declaration) may be more persuasive than written records, such as where records are deemed to be incomplete or inaccurate. Campbell v. Sec'y of Health & Hum. Servs., 69 Fed. Cl. 775, 779 (2006) (“like any norm based upon common sense and experience, this rule should not be treated as an absolute and must yield where the factual predicates for its application are weak or lacking”); Lowrie, 2005 WL 6117475, at *19 (“[w]ritten records which are, themselves, inconsistent, should be accorded less deference than those which are internally consistent”) (quoting Murphy, 23 Cl. Ct. at 733)). Ultimately, a determination regarding a witness's credibility is needed when determining the weight that such testimony should be afforded. Andreu, 569 F.3d at 1379; Bradley v. Sec'y of Health & Hum. Servs., 991 F.2d 1570, 1575 (Fed. Cir. 1993). 35 When witness testimony is offered to overcome the presumption of accuracy afforded to contemporaneous medical records, such testimony must be “consistent, clear, cogent, and compelling.” Sanchez, 2013 WL 1880825, at *3 (citing Blutstein v. Sec'y of Health & Hum. Servs., No. 90–2808V, 1998 WL 408611, at *5 (Fed. Cl. Spec. Mstr. June 30, 1998)). In determining the accuracy and completeness of medical records, the Court of Federal Claims has listed four possible explanations for inconsistencies between contemporaneously created medical records and later testimony: (1) a person's failure to recount to the medical professional everything that happened during the relevant time period; (2) the medical professional's failure to document everything reported to her or him; (3) a person's faulty recollection of the events when presenting testimony; or (4) a person's purposeful recounting of symptoms that did not exist. La Londe v. Sec'y of Health & Hum. Servs., 110 Fed. Cl. 184, 203–04 (2013), aff'd, 746 F.3d 1334 (Fed. Cir. 2014). In making a determination regarding whether to afford greater weight to contemporaneous medical records or other evidence, such as testimony at hearing, there must be evidence that this decision was the result of a rational determination. Burns, 3 F.3d at 417. C. Analysis of Expert Testimony Establishing a sound and reliable medical theory often requires a petitioner to present expert testimony in support of his claim. Lampe v. Sec’y of Health & Hum. Servs., 219 F.3d 1357, 1361 (Fed. Cir. 2000). Vaccine Program expert testimony is usually evaluated according to the factors for analyzing scientific reliability set forth in Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579, 594–96 (1993). See Cedillo v. Sec’y of Health & Hum. Servs., 617 F.3d 1328, 1339 (Fed. Cir. 2010) (citing Terran v. Sec’y of Health & Hum. Servs., 195 F.3d 1302, 1316 (Fed. Cir. 1999). Under Daubert, the factors for analyzing the reliability of testimony are: (1) whether a theory or technique can be (and has been) tested; (2) whether the theory or technique has been subjected to peer review and publication; (3) whether there is a known or potential rate of error and whether there are standards for controlling the error; and (4) whether the theory or technique enjoys general acceptance within a relevant scientific community. Terran, 195 F.3d at 1316 n.2 (citing Daubert, 509 U.S. at 592–95). In the Vaccine Program the Daubert factors play a slightly different role than they do when applied in other federal judicial settings, like the district courts. Typically, Daubert factors are employed by judges (in the performance of their evidentiary gatekeeper roles) to exclude evidence that is unreliable or could confuse a jury. By contrast, in Vaccine Program cases these factors are used in the weighing of the reliability of scientific evidence proffered. Davis v. Sec'y of Health & Hum. Servs., 94 Fed. Cl. 53, 66–67 (2010) (“uniquely in this Circuit, the Daubert factors have been employed also as an acceptable evidentiary-gauging tool with respect to persuasiveness of 36 expert testimony already admitted”). The flexible use of the Daubert factors to evaluate the persuasiveness and reliability of expert testimony has routinely been upheld. See, e.g., Snyder II, 88 Fed. Cl. at 742–45. In this matter (as in numerous other Vaccine Program cases), Daubert has not been employed at the threshold, to determine what evidence should be admitted, but instead to determine whether expert testimony offered is reliable and/or persuasive. Respondent frequently offers one or more experts in order to rebut a petitioner’s case. Where both sides offer expert testimony, a special master's decision may be “based on the credibility of the experts and the relative persuasiveness of their competing theories.” Broekelschen v. Sec'y of Health & Hum. Servs., 618 F.3d 1339, 1347 (Fed. Cir. 2010) (citing Lampe, 219 F.3d at 1362). However, nothing requires the acceptance of an expert's conclusion “connected to existing data only by the ipse dixit of the expert,” especially if “there is simply too great an analytical gap between the data and the opinion proffered.” Snyder, 88 Fed. Cl. at 743 (quoting Gen. Elec. Co. v. Joiner, 522 U.S. 146 (1997)); see also Isaac v. Sec'y of Health & Hum. Servs., No. 08–601V, 2012 WL 3609993, at *17 (Fed. Cl. Spec. Mstr. July 30, 2012), mot. for review den'd, 108 Fed. Cl. 743 (2013), aff'd, 540 F. App’x. 999 (Fed. Cir. 2013) (citing Cedillo, 617 F.3d at 1339). Weighing the relative persuasiveness of competing expert testimony, based on a particular expert's credibility, is part of the overall reliability analysis to which special masters must subject expert testimony in Vaccine Program cases. Moberly, 592 F.3d at 1325–26 (“[a]ssessments as to the reliability of expert testimony often turn on credibility determinations”); see also Porter v. Sec'y of Health & Hum. Servs., 663 F.3d 1242, 1250 (Fed. Cir. 2011) (“this court has unambiguously explained that special masters are expected to consider the credibility of expert witnesses in evaluating petitions for compensation under the Vaccine Act”). ANALYSIS I. Treatment of AIH in Prior Cases The parties agree that Ms. Exum was properly diagnosed with AIH. But even though this is undisputed, some brief discussion of AIH’s characteristics will help in the analysis of causation in this matter. According to Mack, AIH occurs when “a break in self-tolerance to hepatocyte autoantigens initiates immunological responses causing progressive hepatic necroinflammation and fibrogenesis.” Mack at 675, Figure 1. Mack deems AIH to be a “complex genetic disease that requires interplay among genetic, epigenetic, immunologic, and environmental factors.” Id. at 674. It allows that environmental factors like “viral infections or xenophobic disorders” can defeat immune tolerance against autoantigens in genetically-susceptible persons, although it does not mention vaccines. Id. Nonspecific symptoms like fatigue and arthralgias are common to its 37 presentation. Id. at 680; Crippin Rep. at 3, 6. An AIH diagnosis can be confirmed by liver tissue biopsy. Crippin Rep. at 6. The primary articles regarding AIH offered by either side do not appear to embrace the concept that vaccines might in rare cases cause it. At best, they propose an immune-mediated process for how it unfolds. Mack, for example, describes the pathogenesis of AIH as involving a breaking of immune tolerance mediated by a variety of T cells, while cross-reactive autoantibodies (here, presumably incurred due to vaccination) are generated. Mack at 674–76. This is largely consistent with Petitioner’s proposed mechanistic theory. Mack also sets forth a number of specific autoantibodies associated with AIH (although Petitioner has never been shown to have possessed any). Id. at 676–78. But Mack makes no mention of the measles virus as a potential cause of AIH— and its discussion of vaccination-related risks is limited to the context of existing AIH patients receiving immunosuppressive treatments, as opposed to individuals not already experiencing AIH. Id. at 686. 21 Indeed—immunosuppression is a favored treatment of AIH. Mieli-Vergani II at 1, 2, 11 (“AIH should always be treated with immunosuppressive drugs with very few exceptions”). The Vaccine Program has previously considered whether certain covered vaccines can cause AIH—but the trend seems to be against a finding of causation. See, e.g., Porter v. Sec’y of Health & Hum. Servs., 663 F.3d 1242 (Fed. Cir. 2011) (reversing Court’s rejection of special master determination that hepatitis B vaccine was not shown to cause AIH; special master’s decision was reasonably based on credibility determinations about the competing expert opinions, as well as other record evidence). In addition, most such prior claims logically focused on the hepatitis A or B vaccines, since their viral cognates are understood to lead to hepatitis (and indeed, the bulk of the case reports filed in this case better support that kind of causation case than what is advanced here). There are comparatively fewer cases involving the MMR or Tdap vaccines—but those that exist are not favorable to Petitioner. See, e.g., Rivas v. Sec'y of Health & Hum. Servs., No. 21- 1683V, 2025 WL 551570, at *2 (Fed. Cl. Spec. Mstr. Jan. 24, 2025) (“[P]etitioner has not carried her burden of presenting a minimally persuasive case that the Tdap vaccine and hepatitis A and B vaccines can cause and/or worsen autoimmune hepatitis”). II. Petitioner Has Not Met her Burden of Proof under Althen The failure to establish even one of the three Althen prongs in the context of a causation- in-fact claim is sufficient basis for a claim’s dismissal. Dobrydnev v. Sec’y of Health & Hum. Servs., 566 Fed. Appx. 976, 980 (Fed. Cir. 2014). Upon remand, I once again determine that Petitioner did not preponderantly establish causation—at least with respect to the first two Althen 21 Mack actually notes the importance of vaccinating “[p]atients unprotected against infection with hepatitis A virus (HAV) and hepatitis B virus )(HBC)” before they undergo immunosuppressive treatment for AIH. Mack at 686. 38 prongs. (But although the Remand Order affirms the fact that a special master is not compelled to perform analysis of each prong individually, if at least one is found not to have been satisfied (Remand Order at 51), I am including herein my analysis of all three prongs). A. Prong One Petitioner contends that the MMR and Tdap vaccines—alone or in combination—more likely than not can cause AIH. Some elements of the theory are wholly noncontroversial, since they begin with propositions rooted in what is known about the pathogenesis of AIH. Thus, AIH likely occurs due to some combination of individual susceptibility and an environmental trigger. But the theory in its totality lacks sufficient preponderant support, even if some individually- reliable items of literature have been offered in this case. In order to fully meet the Court’s remand mandate, I have explicitly broken down each element of my reasoning for why I find causation has not been demonstrated. 1. Petitioner has Not Preponderantly Demonstrated a Link Between the Measles Component of the MMR Vaccine and AIH The primary thrust of Petitioner’s causation argument was that the measles component of the MMR vaccine has the capacity to suppress the immune response, opening the door thereafter to AIH (with the Tdap vaccine possibly playing a secondary role). There are several flaws with the theory. To an overarching degree, Petitioner’s theory is rooted in a false equivalence between the immunologic impact of the measles wild virus versus the vaccine. 22 Certainly Program claimants often base their theories on the impact a vaccine’s wild viral or bacterial counterpart can have from a pathologic standpoint (since that opens the door to the possibility that a vaccine based on that same wild virus could achieve a comparable effect). And there is reliable evidence that the wild measles infection can cause pathologic harm due to immune suppression—even after the virus has been successfully treated and/or cleared. But the measles wild virus has not been shown to be directly associated with AIH (and instances of liver disease or even AIH associated with hepatitis infections of any kind cannot inform the analysis herein). And it cannot be disputed that the danger posed by the wild measles virus is far greater than the vaccine, all things being equal. See, e.g., McMahon at 635 (measles infections “complications, often due to [virus] induced immunosuppression, occur in up to 30% of cases, and can result in pneumonia, encephalitis, and, in rare cases, death”). Accordingly, it is not facially compelling for Petitioner to assume that vaccination per se involves a risk comparable to the impact of the wild measles infection. 22 See, e.g., Tr. at 37 (Dr. Gish responding affirmatively to the question, “[w]ould it be expected that Mrs. Exum suffered a mild vaccine strain measles infection from the administration of her vaccine?”). 39 More specifically, however, the contention that the measles vaccine is capable of pathologic immune suppression has not been preponderantly established—even if some of the items offered to support this concept have scientific reliability. Both Munyer and Nanan support the narrow proposition that the measles vaccine has been experimentally observed to produce some depression of T cell lymphocyte function—but that is where their findings end. Neither article stands for the conclusion that the studied patients experienced meaningful immune suppression, such that any disease became more likely after receipt of the vaccine (let alone AIH). See, e.g., Munyer at 76. The dated quality of these two items of literature further reduces the weight to be given to them, since they were never followed by confirmatory studies that substantiate the importance of their findings. If it has been known for over twenty years that a measles virus- containing vaccine could produce a dangerous degree of immune suppression, where are the subsequent studies evaluating or testing this purported risk? Thus, the concept that some fairly-old studies produced some evidence of possible vaccine- related suppression needed to be linked to other evidence fleshing out the proposition—not necessarily specific to AIH, but at least to some comparable autoimmune injury. But the evidence Petitioner has offered does not fill these holes in the theory very well. Christen, for example, only briefly mentions the measles vaccine, but notes that evidence connecting it to AIH was not corroborated over time. Christen at 43. Christen similarly mentions a case series article never filed in this case (Vento), and which observed only a temporal association between measles and AIH. And it references Mieli-Vergani I as the ultimately-uncorroborated measles virus-AIH connection—while the same primary author (in the more recently-published Mieli-Vergani II) made no mention at all of measles virus as a putative AIH trigger (suggesting that in the 30 years that passed between the two articles, the measles trigger hypothesis was no longer considered important). Robertson is fairly weak support for the proposed measles-AIH link. It may well show (in a small sample) that a preexisting measles infection might be associated with an AIH-like condition. Yet (and in addition to the fact, noted in Christen, that Mieli-Vergani I did not corroborate its potential findings—and that the illness considered may not be on all fours with AIH) it says little about the impact of receipt of a measles-containing vaccine. I therefore do not find that even the nascent possibility outlined in Nanan and Munyer has been subsequently confirmed or carried forward—meaning in turn that this aspect of Dr. Gish’s theory lacks sufficient reliable support to corroborate it. I also emphasize that the argument that the measles vaccine component can cause pathologic immune suppression is hardly new to the Program. In fact, it was a central pillar of the causation theory advanced in the Omnibus Autism Proceeding (the “OAP”) over 15 years ago, about the alleged capacity of the MMR vaccine to cause autism. But (after a matter characterized 40 by a lengthy and laborious degree of fact-finding unheard of in the Program, before or since) 23 the idea that pathologic immune suppression could be caused by this vaccine was firmly rejected. See, e.g., Snyder v. Sec'y of Health & Hum. Servs., No. 01-162V, 2009 WL 332044, at *104 (Fed. Cl. Spec. Mstr. Feb. 12, 2009) (“petitioners have failed to demonstrate that the MMR vaccine causes immunosuppression. There is no evidence that children receiving the vaccine have higher rates of infection in the months after vaccination than children who do not receive the vaccine”), mot. for review den’d, 88 Fed. Cl. 706 (2009). Notably, Nanan and Munyer were published before Snyder’s issuance—again raising the question as to why, if they stand as reliable and persuasive evidence of MMR vaccine-caused immune suppression, there are not any more recent follow-up studies corroborative of their findings. And subsequent decisions considering the same proposition (admittedly, also in the context of an autism injury claim) have rejected the theory again, even where such articles were expressly invoked in support. See, e.g., Reed v. Sec'y of Health & Hum. Servs., No. 08-650V, 2018 WL 6844458, at *47 (Fed. Cl. Spec. Mstr. Dec. 4, 2018) (rejecting contention that MMR vaccine can cause clinically meaningful immunosuppression resulting in autism, and discussing Munyer’s limits as persuasive evidence to that point). Petitioner’s immunosuppression argument is further weakened by Respondent’s counterevidence, which supports the conclusion that the measles vaccine actually makes immune suppression far less likely—simply by reducing the possibility of a measles infection in the first place. See e.g., Mina at S10 (noting that measles vaccine is correlated with large reductions in childhood mortality because direct heterologous benefits of the vaccine enhance innate and adaptive immune responses). And there is a contradictory quality to arguing that immune suppression would cause a disease reaction that is the product of an uncontrolled immune response—since autoimmunity involves an unregulated attack by the immune system against self. In fact, as Dr. Crippin noted, immunosuppressive treatments are used for AIH, and Petitioner herself received them (Crippin Rep. at 3). How does measles-induced immunosuppression lead to a disease that itself is treated by immune suppressive drugs? Mieli-Vergani II at 1, 2, 11. This contradiction is unanswered by Dr. Gish. Otherwise, the evidence of a direct MMR vaccine-AIH connection is largely absent. 24 It is limited to a single case report, Saliba (with Veerappan providing one additional case involving the 23 See Hooker v. Sec'y of Health & Hum. Servs., No. 02-472V, 2017 WL 3033940, at *4–6 (Fed. Cl. Spec. Mstr. Apr. 11, 2017), for a summary of the OAP process. The work performed by the three special masters who jointly heard evidence in the OAP, and then wrote the formidably-long entitlement decisions thereafter, was exemplary—and thus findings made therein that have relevance to other kinds of Vaccine Act claims deserve considerable weight, even if they do not control the outcome herein. 24 My observation that this evidence is lacking is not the same as requiring it. I am simply noting that the evidence of a more direct vaccine-AIH association is not evident (underscoring the degree to which Petitioner must rely on more indirect and circumstantial proof—and here, that proof too proves inadequate). 41 MMR, but too many other additional vaccines to separate out possible triggers). This is not enough of a link to remedy the other deficiencies in this aspect of Petitioner’s causation theory. I thus do not find on this record that it is preponderantly likely that the MMR vaccine can cause sufficient levels of immune suppression to have a clinically-meaningful impact—such that it could establish conditions for an autoimmune disease like AIH. 2. Evidence About the Putative Role of the Tdap Vaccine in Causing AIH is Weak or Lacking Dr. Gish devoted less time at trial to explaining his theory for how the Tdap vaccine could play into the proposed pathogenesis for AIH. But this aspect of the overall theory made assumptions about the impact of the Tdap vaccine (and its promotion of inflammation through stimulation of T-helper cells) that arise more from supposition than independent evidence. Petitioner contends that an upregulation of T helper cells due to receipt of a Tdap booster could in turn cause pro-inflammatory cytokines secreted by those T helper cells to encourage an autoimmune disease process. First Gish Rep. at 21–22. The limited evidence that he offered for this was unconvincing. In van Gemeren, for example, a woman developed AIH after receiving multiple vaccines, including the Tdap vaccine. van Gemeren at 19. But the authors of this case report did not include any discussion of the Tdap vaccine. Id. Instead, they narrowed in on the hepatitis A vaccine as a potential trigger. Id. at 21–22. da Silva Antunes admittedly provided some evidence relevant to this argument, finding that people previously vaccinated with the whole cell pertussis vaccine produce more IL17 cytokines after booster vaccination (for the subset of the sample that previously received a whole cell pertussis version of the vaccine—presumably true of Petitioner as well). da Silva Antunes at 3–4. But does this mean that the levels of cytokines generated in reaction would be enough to be pathogenic—if not in the specific context of AIH, then with respect to any autoimmune disease? da Silva Antunes does not say. And its more limited observation was rooted in an evaluation of the comparative immunologic value of acellular versus whole-cell pertussis - not the pathogenic potential of the Tdap vaccine. da Silva Antunes at 3855–56. The article includes no discussion of AIH. And Dr. MacGinnitie persuasively also pointed out that the sample size of the da Silva Antunes study was limited, that it did not observe large increases in the production of these cytokine-generating helper cells, and otherwise that these T cells themselves are not considered per se pathogenic in any event. First MacGinnitie Rep. at 9–10. Lafdil does not bridge this evidentiary gap sufficiently. It does observe that T-helper cells play some role in the development of autoimmune liver disease—in particular through encouragement of a kind of pro-inflammatory cytokine associated with different kinds of liver illnesses—some of which are analogous to AIH. Lafdil at 250, 251–52. Again, however—does 42 this lead to the conclusion that receipt of a Tdap booster is likely to raise these cytokines to pathogenic levels, and thereupon spur on AIH? Lafdil does not so conclude, and it is speculative to do so here. Petitioner has only shown that there is scientific support for the conclusion that this kind of T helper cell is involved in an AIH-like disease process. But that is not the same as the determination that vaccination likely leads to the disease process. There are too many missing links in the causation chain to so conclude. Overall, this element of the causation theory reflects Petitioner’s continued effort to transmute narrow, scientifically-reliable facts (derived from limited but methodologically reasonable studies) into a basis for pathology which itself is ultimately speculative. Even if a Tdap booster results in the production of certain T cells that could be associated with autoimmune disease, this does not mean they drive or initiate that disease—or that they are upregulated by vaccination in amounts sufficient to cause disease. And Petitioner’s showing, in the absence of other evidence implicating the Tdap vaccine (or its viral/bacterial components) to AIH, is even more faint in supporting causation. 3. Insufficient Evidence Was Offered to Establish The Risk of Receiving Two Vaccines at Once Dr. Gish argues that the administration of both vaccines at the same time raised the risk of an aberrant response. Tr. at 51, 63. But this is a barely plausible contention that lacked corroboration from materials filed in this case. No studies were offered that evaluated via a trustworthy methodologic experiment the impact of receiving two vaccines at the same time – in the context of any autoimmune disease. At most, some case reports were filed in which at least one of the relevant vaccines was administered. See, e.g., Veerappan, van Gemeren. While the authors of Veerappan suggest that AIH may be a complication in patients who receive multiple vaccinations simultaneously, they do not explain why. Veerappan at 212. And in Veerappan, the patient received four vaccines simultaneously, as opposed to Petitioner’s two. (Otherwise, and as discussed in greater detail below, there is no evidence in the contemporaneous medical record at all of any suspect, close-in-time reaction to the vaccines Petitioner received on August 20, 2018— further distinguishing the present case from Veerappan). 4. Dr. Gish’s Molecular Mimicry Mechanism for Driving AIH Due to Vaccination Was Inadequately Corroborated Admittedly, Petitioner in this case did not primarily rely on a theory that antigenic similarity between components of either vaccine she received and protein components in the liver caused an autoimmune cross-reaction, resulting in AIH. Dr. Gish, however, did invoke the concept as a reliable mechanistic explanation for autoimmune disease. See, e.g., First Gish Rep. at 10, 17, 43 20–21. But he did not substantiate it adequately either, such that I could find it might stand as a reliable mechanism explaining how the two relevant vaccines, alone or in combination, could lead to AIH. Some autoimmune diseases can be mediated by mistaken self-attacks propagated by antibodies generated in response to a foreign antigen that (due to molecular and/or structural similarities with a self-antigen protein) then cross-react with the self tissue, often in a chronic/persistent manner. See, e.g., Bielak v. Sec'y of Health & Hum. Servs., No. 18-761V, 2023 WL 35509, at *33 (Fed. Cl. Spec. Mstr. Jan. 3, 2023) (“[m]olecular mimicry is predominantly driven by B cell activity, occurring when antibodies are produced in response to antigenic components of the vaccine—but which (due to mimicry between the presenting vaccine antigens and self-tissues) cause harmful cross-reactions, by mistakenly attacking the self antigens”). Because vaccines are usually designed to encourage an adaptive response to a foreign antigen specifically by “teaching” the immune response to create antibodies to attack the antigen in future exposures, the mechanism of molecular mimicry fits well with theories that the immune response to vaccination could become pathologic. But litigants who invoke molecular mimicry to explain how a vaccine could have triggered an autoimmune disease commonly attempt to show at a minimum (a) what homology might exist between a vaccine’s antigens and a self-structure relevant to the situs of harm (here the liver), and (b) what evidence exists that the vaccine would cause the production of the likely pathogenic antibodies. See K.A. v. Sec'y of Health & Hum. Servs., No. 16-989V, 2022 WL 20213037, at *9 (Fed. Cl. Spec. Mstr. Apr. 18, 2022), mot. for review den’d, 164 Fed. Cl. 98 (2022), aff'd, 2024 WL 2012526 (Fed. Cir. May 7, 2024) (“[b]ecause homology is common in nature (given the total limited number of amino acids that constitute proteins), it is important to focus on homology specific to the “disease-related” situs for the cross- reactive attack”). Here, however, Dr. Gish has not made a homology showing—which, as Dr. MacGinnitie noted, is by itself not enough evidence to conclude an autoimmune process linked to vaccination has been established. He also did not otherwise offer evidence suggesting that the vaccines or their wild viral counterparts are associated with any antibodies thought to drive AIH or be involved in its pathogenesis. There is thus very little evidence in this record that would support molecular mimicry due to vaccination as a mechanistic explanation for AIH. In reaching my conclusion about the strength and applicability of molecular mimicry as a mechanism in this case, I acknowledge that petitioners need not offer any mechanism at all in proving causation. Andreu, 569 F.3d at 1378–79. But what does this mean, in a case where the Petitioner’s expert did offer several possible mechanisms? Is the special master obligated to avert his eyes from the strength of the evidence at issue? Must he simply assume a briefly-invoked mechanism reasonable, without consideration of the weaknesses noted in it by Respondent? Relevant and controlling case law says otherwise. Howard v. Sec'y of Health & Hum. Servs., No. 16-1592V, 2022 WL 4869354, at *24 (“[o]f course, petitioners are never required to 44 establish mechanism—but they often attempt to do so, and therefore it is reasonable to evaluate their success in the effort”) (Fed. Cl. Spec. Mstr. Aug. 31, 2022), mot. for review den’d, 2023 WL 4117370 (Fed. Cl. May 18, 2023), aff'd, 2024 WL 2873301 (Fed. Cir. June 7, 2024). I may evaluate whether a proposed pathologic mechanism has been evidentiarily supported—and this one has not. Claimants cannot both invoke a possible mechanism to flesh out their causation theory, but then evade its deficiencies by objecting they were never obligated to prove it in the first place. 5. Case Reports are Weak Causation Evidence, and Those Offered Were Largely Unhelpful to Petitioner Petitioner offers a number of case reports in support of her causation argument. See Saliba, Sasaki, Perumalswami, Subramanian, van Gemeren, Berry, Veerappan. At the outset, however, it is plain that several of them (Berry, Perumalswami, Sasaki) do not involve the Tdap or MMR vaccines (or even comparable wild virus infections). Berry, Perumalswami, and van Gemeren involve the hepatitis A and/or B vaccine; Subramanian a hepatitis A wild infection; and Sasaki the flu vaccine. This fundamental fact distinction greatly saps such case reports of evidentiary value in the context of this case. See Herms v. Sec'y of Health & Hum. Servs., No. 19-70V, 2024 WL 1340669, at *21 (Fed. Cl. Spec. Mstr. Mar. 4, 2024) (“Petitioner does not explain how data from other unrelated vaccines could be extrapolated to the vaccines at issue here and accordingly, the data is not persuasive”), mot. for review den’d, 173 Fed. Cl. 1 (2024); see also Deshler v. Sec'y of Health & Hum. Servs., No. 16-1070V, 2020 WL 4593162, at *19–21 (Fed. Cl. Spec. Mstr. July 1, 2020) (declining to attribute case reports on the flu vaccine to the causation potential of pneumococcal vaccines). Saliba is the most factually-relevant case report, since it involves a patient who developed hepatitis after receipt of the MMR vaccine. Saliba at 379. But the patient in Saliba experienced acute hepatitis, which is distinguishable from AIH, a chronic condition. Additionally, the patient in Saliba developed obvious symptoms of liver disease within two weeks of vaccination, while Petitioner’s first confirmed symptom (elevated liver enzymes) appeared two months post- vaccination. It is thus factually distinguishable in important respects. In a larger sense, case reports are of limited value in determining causation—even when they are factually relevant. Special masters have repeatedly observed that case reports present only a temporal sequence of events, and thus stand as very thin evidence of causation. Demore v. Sec'y of Health & Hum. Servs., No. 20-1265V, 2024 WL 4542934, at *7 (Fed. Cl. Sept. 26, 2024), aff'd, No. 20-1265V, 2025 WL 868902 (Fed. Cl. Mar. 20, 2025); see also Campbell v. Sec'y of Health & Hum. Servs., 97 Fed. Cl. 650, 668 (2011) (“‘[c]ase reports do not purport to establish causation definitively, and this deficiency does indeed reduce their evidentiary value,’ even if they should receive some weight”). 45 Dr. Gish devoted much of his supplemental expert report to attempting to defend case reports, especially given the rarity of vaccine injuries. See generally Second Gish Rep. at 1–4. But his reasoning rings hollow. A case report may be the place to start a causation inquiry, but that effort must then build upon other evidence that suggests the temporal/coincidental observation of post-vaccination injury is scientifically meaningful. And here, the paucity of case reports specific to the vaccines at issue and AIH do not appreciably add to the total picture. Dr. Gish reasons that case reports suggest a one-time occurrence might repeat elsewhere (Second Gish Rep. at 3 (“if something did happen in another person, then logically the event can happen in this patient”)—but this kind of logic does not pass muster in the Vaccine Program when uncorroborated with other evidence. 6. Other Proposed Mechanisms Were Inadequately Developed Petitioner’s causation showing included a number of additional independent theories or mechanisms that were only briefly touched upon, but never substantiated into something sufficient to be deemed preponderantly established. These contentions accordingly merit even less weight than the better fleshed-out aspects of the causation theory discussed above, like the proposed impact of measles vaccine-associated immune suppression. For example, as evidence for the contention that the measles vaccine component could literally “infect” certain immune cells, Petitioner referenced Rennick. But as I have noted above, an article like Rennick has more to say about the function of the measles vaccine from an immunologic standpoint than it does about the vaccine’s allegedly-pathogenic capacity (which is what is at issue in this case). Its observation about the way the vaccine’s antigens are taken up by immune cells cannot be alone stretched into a finding that this in turn increases the likelihood the vaccine will, at some later time, unexpectedly cause measles-associated immune suppression of some kind. Thus, Rennick stands as another instance in which Petitioner seeks to take anodyne scientific findings about vaccine performance and speculatively recast them into proof of pathology. Petitioner proposed bystander activation of nonspecific immune cells (and/or suppression leading to expansion of these immune cells) as another way AIH might occur. First Gish Rep. at 9, 10; Tr. at 42, 58. But there was inadequate evidence supporting this mechanism as likely causal of AIH due to vaccination. 25 Dr. MacGinnitie persuasively explained that usually bystander activation would only be thought to occur in the presence of active inflammation due to an infectious process (which was never shown to have happened in this case). Tr. at 158–60. And 25 In fact, articles like Mack did not even mention bystander activation as an understood mechanism for AIH (Tr. at 160)—although Dr. MacGinnitie admitted on cross-examination that Mina mentioned bystander activation as something a vaccine could encourage—blunting this contention somewhat. 46 articles like Benn are focused on the positive, secondary effects of this kind of nonspecific immune stimulation, rather than supporting the contention that vaccine-associated bystander activation is harmful. Benn at 432, 436–37. Dr. Gish also spoke generally of immune tolerance being broken by a T cell-driven process, resulting in harm to liver cells. Tr. at 53–54; Petitioner’s Post-Hearing Brief, filed May 31, 2024 (ECF No. 73) (“Br.”) at 9. This is consistent with how AIH likely unfolds—but a description of the pathogenesis of the disease in question does not also establish causation, if not yoked to sufficient reliable proof to conclude the vaccine can be an aspect of the disease process. I have already observed above that explanations like measles-associated immunosuppression, or Tdap booster-driven T helper cell increases, do not “work.” And certainly no other, more direct evidence was offered to show how these vaccines would break immune tolerance. Petitioner could not simply take a truism about the illness in question and then turn that into evidence of vaccine- instigated pathology, without better and more persuasive proof. 7. Respondent’s Experts Were More Persuasive Than Dr. Gish on the Question of Vaccine Causation Another factor bearing on my prong one determination is my assessment of the experts, who I saw and heard live at hearing. Dr. Gish was certainly qualified to offer an opinion in this case as a general matter, given his expertise in hepatology. But he has no specific expertise studying AIH’s pathogenesis (even if he has a background in the treatment of liver-associated diseases, and has some reasonable insights gleaned from that experience). In addition, he was matched against another, equally-qualified hepatologist (Dr. Crippin) who also reasonably relied on his own experience in questioning causation. Worse, Dr. Gish lacks demonstrated expertise in the field of immunology—and the opinions he offered on this subject were persuasively rebutted by Dr. MacGinnitie—the sole immunologist who testified herein. I therefore have given Dr. Gish’s generalized and somewhat broad contentions about the alleged immune process that could lead to AIH post-vaccination less weight than the Respondent’s experts’ testimony. This is not a case where I deemed an expert to have lacked core “credibility.” 26 But weighing of expert testimony is not limited to determining bare-bones questions of personal honesty or truthfulness. Nor does Program law ever compel me to accept an expert’s ipse dixit. Snyder II, 88 Fed. Cl. at 743. While Dr. Gish presented an opinion favorable to Petitioner, that was not the end of my evaluation of it—and as discussed herein, I deem it ultimately wanting, since 26 I do, however, share the opinion offered by Dr. MacGinnitie that it was “difficult to follow a logical, step by step theory of causation in Dr. Gish’s Report,” which was excessively wordy, meandering, and unclear in the theory it embraced. MacGinnitie Rep. at 6. His enunciation of that theory at hearing was not much more illuminating—and although I have attempted to summarize his views in a more ordered fashion, it has not been easy (and this also detracts from the theory’s persuasiveness). 47 it was unsupported by sufficient corroborating evidence. Dr. Gish too often tried to leverage things known about AIH into proof of vaccine pathology, without sufficient connective evidence; exaggerated the impacts of the measles vaccine into a disease process; and relied on older studies that have not been subsequently shown to have the same significance they might once have been thought to possess. Dr. Gish’s theory did not add up, independent of his expertise as a hepatologist, and even if some of its components were individually reliable. In summary: Petitioner was unable to establish that the Tdap vaccine and/or MMR vaccine can likely cause autoimmune hepatitis. I make this finding based on an in-depth review of all the evidence presented by both parties. Petitioner has not provided enough reliable evidence that the MMR vaccine causes clinically significant immunosuppression leading to an autoimmune disease like AIH. For these reasons, I find that the first Althen prong is unsatisfied. B. Althen Prong Two Under the second Althen prong, a petitioner must prove actual causation—that the vaccine(s) at issue “did cause” the alleged injury/illness—by a preponderance of the evidence. Boatmon, 941 F.3d at 1355. The evidence in the record for this matter does not so preponderate. I mostly base this determination on the absence of objective record proof from which it could be inferred that Petitioner’s August 20, 2018 vaccinations caused any aberrant reaction. Thus, Petitioner’s medical records contemporaneous to her vaccination date are devoid of evidence that she experienced any close-in-time vaccine reaction. In addition, she never tested positive for inflammation biomarkers that might corroborate that she was experiencing some kind of inflammatory event before her liver test values became elevated. Petitioner was not shown to have possessed an active measles infection (key to Dr. Gish’s opinion about suppression), and was not demonstrated to be experiencing any form of hepatitis infection, or even any other opportunistic infectious process that could be thought to have occurred in the wake of the alleged measles vaccine-caused immune suppression (and thus might demonstrate indirectly that she was then suffering from immune suppression). I also have not ascertained any instance where any of Petitioner’s treaters proposed the vaccinations explained her AIH (including Drs. Oloruntoba or Wu). What remains is the fact that Petitioner experienced some post-travel nonspecific symptoms which did not immediately merit treatment (and which arguably were consistent with her pre-vaccination health). While these concerns (in particular, fatigue) seem likely related to Petitioner’s subsequently-diagnosed AIH, they are not enough of a basis to conclude that the two vaccines Petitioner received “did cause” her AIH. Petitioner received the two vaccines, traveled abroad, then a few weeks later felt fatigue, and then inadvertently was found to possess elevated LFTs. To deem this sufficient to establish “a logical sequence of cause and effect” as required for 48 the “did cause” prong would be to elevate the temporal relationship between vaccination and injury (here, already somewhat attenuated) into compelling proof of causation. Grant v. Sec'y of Health & Hum. Servs., 956 F.2d 1144, 1148 (Fed. Cir. 1992) (“[a] proximate temporal association alone does not suffice to show a causal link between the vaccination and the injury”). 27 It is also very important to give weight to the circumstances in which Petitioner received these vaccines—for her vaccinations did not occur in a vacuum. While Dr. Gish did observe the absence of some risk factors for AIH relevant to Petitioner (for example, she had not tested positive for a hepatitis viral infection), he did not persuasively account for the risk factors that were present —even though he acknowledged the relevance of this kind of evidence to causation. Tr. at 20 (Dr. Gish testifying that reviewing an individual’s medication history is “really key” to determining what may have caused AIH). Petitioner’s recent post-vaccination foreign travel (which clearly could have exposed her to any number of possible pathogens), plus her acknowledged receipt of anti-malarial medications and supplements, were all potential causal factors. The anti-malarial medication Petitioner received is an example of the kind of confounding factor undermining vaccines as causal in this case. It is well-established that medication toxicity is a risk factor for liver dysfunction. See e.g., Tr. at 86 (Dr. Gish acknowledging the existence of drug-induced liver disease). And in Beretta-Piccoli, a patient developed long-term autoimmune hepatitis (comparable to AIH) while taking the same anti-malarial medication as Petitioner. Beretta-Piccoli at 293–95. The fact that this case report patient developed hepatitis on two separate occasions while taking this medication led the authors to conclude that the medication was “likely” the cause of the patient’s liver pathology. Id. at 296. And the patient in Beretta-Piccoli stopped taking the anti-malaria meds four days before she presented at the hospital, but still developed AIH. Beretta-Piccoli at 294. Admittedly, it cannot be concluded from this record that the anti-malarial medication likely caused Petitioner’s AIH. Dr. Gish reasonably noted that this medication typically does not result in long-term autoimmune disease, and/or should cause harm closer-in-time to when the medication is being taken. He similarly pointed out some factual differences in the form of hepatitis at issue, as well as the relevance of when the medication is taken in comparison to onset. And I am reluctant to give great weight to a case report of any kind – whether offered by Respondent or Petitioner. 28 27 For this same reason, I do not give weight to the pre-vaccination absence of evidence of liver disease or hepatitis as proof of the vaccine’s role in causing what manifested after. The fact a claimant was not sick before the vaccination, but sick after, is simply another form of post hoc ergo propter hoc reasoning that the Program rejects. 28 Of course, if the “signal” of otherwise-factually distinguishable case reports like Saliba should be viewed as credible evidence of causation—as Petitioner urges—then there is no reason to downplay the findings of Beretta-Piccoli simply because Dr. Gish observes some factual distinctions between that case and the present facts. The same distinctions are true for Saliba, which involved acute hepatitis and a short onset—and as the adage goes, “sauce for the goose is sauce for the gander.” I also note that Beretta-Piccoli is considerably more substantive in its analysis than Saliba – the most on-point case report offered by Petitioner, but which takes the form of a one-page “letter to the editor,” and includes far less consideration of causality. 49 But this medication is clearly something that had a demonstrated capacity to increase Petitioner’s possible hepatitis risk, and she received it after vaccination (and hence closer in time to her possible onset). I am not, on the basis of this record, able to determine what did likely cause Petitioner’s AIH—and I do not find Respondent preponderantly established a different trigger. But entitlement is not properly granted simply because Respondent cannot “prove” an alternative to vaccination as the cause. Winkler v. Sec'y of Health & Hum. Servs., 88 F.4th 958, 963 (Fed. Cir. 2023) (“the failure to prove an alternate cause does not obviate the need for proof of causation by the vaccine”). Only when a claimant has met his initial prima facie case is Respondent even burdened with proving a “factor unrelated.” Section 13(a)(1)(B); Althen, 418 F.3d at 1278. And I have not found the burden should be, or was, shifted here. 29 The Court’s Remand Order accurately observed that there can be a “fine line” between noting the existence of evidence of alternative explanations for a claimant’s injury, and actually requiring the Petitioner to disprove them. Remand Order at 50 (citing Sharpe v. Sec'y of Health & Hum. Servs., 964 F.3d 1072 (Fed. Cir. 2020)). And petitioners are never obligated formally to disprove alternative causal factors. Walther v. Sec'y of Health & Hum. Servs., 485 F.3d 1146, 1149–50 (Fed. Cir. 2007) (citing Pafford, 451 F.3d at 1359). But it is fully appropriate for special masters to evaluate and weigh record evidence of contrary possible explanations for an injury in assessing a claimant’s prong two success. Winkler, 88 F.4th at 963 (“contemplation of a potential causative agent when evaluating whether or not a petitioner has established a prima facie case is in accordance with the law”); Stone v. Sec'y of Health & Hum. Servs., 676 F.3d 1373, 1380 (Fed. Cir. 2012) (“[t]he special master is entitled to consider the record as a whole...and no evidence should be embargoed from the special master's consideration simply because it is also relevant to another inquiry under the statute”). This weighing reasonably includes review of evidence about the Petitioner’s health or other circumstances bearing on their illness. 30 29 I have conducted the burden-shifted “factor unrelated” analysis in cases where a petitioner carried his initial burden—and the outcome thereafter has varied, depending upon the record and expert evidence offered to interpret it. Compare White v. Sec'y of Health & Hum. Servs., No. 20-1319V, 2023 WL 4204568 (Fed. Cl. Spec. Mstr. June 2, 2023) (infection caused petitioner’s GBS as factor unrelated, even though prima facie Table claim of GBS after receipt of flu vaccine was met), mot. for review den’d, 168 Fed. Cl. 660 (2023), appeal docketed, No. 2024-1372 (Fed. Cir. Jan. 23, 2024), with Taylor v. Sec'y of Health & Hum. Servs., No. 22-335V, 2025 WL 1234906 (Fed. Cl. Spec. Mstr. Mar. 25, 2025) (Respondent did not preponderantly demonstrate factor unrelated of CMV infection as causal of petitioner’s GBS in flu-GBS Table claim). 30 I have done that very thing in many other cases, and my determinations have been subsequently upheld. For example, I denied entitlement in a case in which a claimant alleged the Tdap vaccine had caused him to experience GBS. See K.A. v. Sec'y of Health & Hum. Servs., No. 16-989V, 2022 WL 20213037 (Fed. Cl. Spec. Mstr. Apr. 18, 2022), mot. for review den’d, 164 Fed. Cl. 98 (2022), aff'd, 2024 WL 2012526 (Fed. Cir. May 7, 2024). I found (among other things) that the Petitioner’s personal medical records suggested that an upper respiratory infection he had experienced around the time of his GBS onset might have been causal of it, and therefore that this fact pattern inhibited his ability to meet the second Althen prong. K.A., 2022 WL 20213037, at *30–32. Many special masters have found Althen prong 50 The second prong is not a meaningless obligation, as the Circuit has noted. Capizzano, 440 F.3d at 1327. Petitioners do not simply prove the “can cause” element, and then rely on the fact of the injury itself to do all the work in establishing a “logical sequence of cause and effect.” Rather, in any Vaccine Act claim, many factors arising out of the circumstances in which a vaccination occurred can come into play in contributing to a disease or illness—and they are properly weighed even if the prong one, “can cause” requirement has indisputably been met. Petitioners must grapple with the actual record before them, and persuasively deal with factors undermining the conclusion that one or more vaccines caused an injury. This does not mean they must disprove alternative causes. In this case, there are simply too many confounding factors specific to Petitioner’s experiences in the six-to-eight-week post-vaccination period for me to conclude it more likely than not that the Tdap and MMR vaccines contributed to her AIH. Nor has she demonstrated other factors consistent with her theory (other than the circular point that she in fact developed AIH post- vaccination) that would corroborate it. The medical record simply does not contain sufficient facts suggesting the vaccines had anything to do with Petitioner’s disease. The second Althen prong has not been preponderantly established. C. Althen Prong Three Petitioner’s showing on this prong requires demonstrating (a) when her AIH most likely began, and then (b) whether that occurred in a medically-acceptable timeframe, measured from the date of vaccination. On the former fact question, the record does not permit a clear determination of any kind (making it impossible in turn to identify whether the timeframe from vaccination to onset of AIH was medically acceptable). Dr. Gish himself was ambivalent in identifying a specific onset date. He deemed significant Petitioner’s LFT findings from her late-October 2018 physical, citing them as clear support for the diagnosis. These findings were obtained 68 days, or more than two months, post-vaccination. This is facially a long timeframe, especially in the context of a record lacking much evidence of symptoms progression, or even an identifiable vaccine reaction. But arguably this could amount to confusing when an AIH diagnosis could be made with when Petitioner’s disease course actually began—the latter being the more important question for purposes of the third prong. Carson v. Sec'y of Health & Human Servs., 727 F.3d 1365, 1369 (Fed. Cir. 2013) (Vaccine Act limitations period begins to run from the manifestation of the first objectively cognizable symptom, whether or not that symptom is sufficient for diagnosis). It is highly likely Petitioner’s AIH began before the late October test results were obtained—and at trial Dr. Gish seemed to embrace an onset earlier than late October. one met in such cases—but this determination would not mean the same for prong two, if other factual evidence undermined the vaccine as specifically causal in a petitioner’s own circumstances. 51 Some faint evidence of fatigue and nausea experienced by Petitioner over a several-week period, from early September to mid-October, could constitute her AIH onset. These symptoms are nonspecific for AIH, while also being consistent with other comorbid concerns Petitioner suffered from, such as kidney stones or gastrointestinal issues (like GERD). But they are also reasonably associated with AIH. At the same time, Petitioner never reported any concerning or unusual reaction to the vaccines she received, and there is no record proof (clinical or testing results) of the presence of concerning inflammation in September or October 2018 either. And the purpose of Petitioner’s October physical was not to address any then-alarming symptoms, nor does it appear that Petitioner reported such concerns at that time (despite Petitioner’s contentions about daily nausea that month). All of the above makes it exceedingly difficult to pinpoint an onset date for evaluation under the third Althen prong. Treaters like Drs. Oloruntoba and Wu seem to have assumed, however, that Petitioner’s overall course—fatigue and some nausea after return from her travels, then the inadvertent discovery of LFT elevated levels, culminating in her December 2018 presentation—reflected a single disease process. Thus, she experienced some clinical features of early AIH within six to eight weeks of vaccination, later corroborated by the LFT test results, and progressing to more concerning symptoms that led her to seek treatment in December, after which she was more formally diagnosed. Such an onset would fall into the temporal interval proposed under Dr. Gish’s theory. Indeed, even Dr. MacGinnitie seemed to agree that an autoimmune process triggered by the immune stimulation of a vaccination might first manifest within six to eight weeks of the trigger. Tr. at 176. Accordingly—had I found the Tdap and MMR vaccines could cause AIH in the manner proposed by Dr. Gish, I would also be able to find Petitioner’s onset occurred in a medically- acceptable, post-vaccination timeframe. Of course, I have not found prong one was satisfied—and therefore it does not matter that Petitioner’s likely onset is consistent with that theory. I also note that the vagueness of the evidence relating to onset is comparable to the same overall lack of record support for prong two. Just as Petitioner’s own medical record does not preponderantly establish vaccination as the likely actual cause of her AIH, that record also makes it exceedingly difficult even to say when her AIH began. III. Comment on Application of Preponderance Test to Petitioner’s Showing The Court has concurred with my enunciation of the preponderance test as individually applicable to each Althen prong. Remand Order at 37–38. But the Remand Order nevertheless expressed concern that my vacated entitlement decision inadequately explained why this test was not met overall. Id. at 44. Hopefully the exhaustive re-review and discussion of the record I have now provided assuages those concerns. But it is possible that Petitioner will seek further review of my decision, arguing once again that her evidentiary showing did in fact meet the preponderance test. I will 52 therefore conclude with a few points about the application of the preponderance standard in Vaccine Act claims. Preponderance is not met on the basis of the amount of evidence filed. 100 items of evidence do not “beat” 50 simply due to numerical superiority, or the physical weight of paper if placed on a scale. And claimants do not “double-prove” their case by offering multiple overlapping items of literature that effectively say the same thing. What matters is the individual reliability of the items of evidence offered, coupled with how well each item knits together into an overall theory that does not amount to speculation or unreasonable extrapolation. Similarly, establishing preponderance does not turn on the fact that a claimant has offered something in support of their claim. Determining causation is not an exercise of ensuring that each Althen prong “bucket” has been filled with some evidence that is not obviously fraudulent or false. Rather, special masters are expressly called to weigh the totality of evidence offered, pro and con. In so doing, they make reliability findings for theories based on the chain of propositions or building-blocks offered. And in performing these assessments, they may find that a petitioner’s showing fails to cross the “more likely than not” line—even if individual items of evidence still merit weight. In addition, the fact that vaccine injuries are (thankfully) rare events does not excuse a claimant from the burden of the preponderant test—nor does it mean that preponderance becomes a function of what evidence is available at a given time. As the Court has recognized, “the standard of proof does not operate as a sliding scale that varies depending upon the quantity and quality of the scientific evidence that is available.” Caves v. Sec'y of Health & Hum. Servs., 100 Fed. Cl. 119, 143 (2011), aff'd, 463 F.App'x 932 (Fed. Cir. 2012). Even if there is generally little in the way of independent research or findings bearing on a proposed theory to begin with, petitioners do not get graded on a curve. My evaluation of this claim also does not amount to a heightening of the preponderant burden, requiring certainty even though the evidentiary test does not. It has been my experience as a special master that I can never be certain a vaccine did, or did not, cause a given injury— regardless of the case’s outcome. Special masters are called upon only to evaluate the likelihood of causality, based on the totality of evidence. Cases turn on how, and in what direction, that evidence tips. Here, a preponderant evidentiary showing has not been made—and it was not a close case. This is yet another instance in which a claimant wants to leverage a set of basic facts about a disease process and immunology into an explanation for pathology. But that is difficult to do— even if the core concepts are reasonable. As a special master, I have in the past 12 years reviewed hundreds of claims. In nearly every such disputed case where the injury was autoimmune in nature, a good faith argument could be made that vaccination (even where distantly-administered in time) could set up a process leading to the injury, simply due to the obvious fact that vaccination impacts the human immune system. There are any number of experts prepared to offer an opinion sketching 53 out the process of how that might occur, relying on what is medically/scientifically known about immunology. And they do so invariably in “a field bereft of complete and direct proof of how vaccines affect the human body,” (Althen, 418 F.3d at 1280). Even so, such claims do not automatically prevail. To meet the preponderant standard, sufficient evidence must be presented to allow for the conclusion that the vaccine “more likely than not” acted as proposed. That was not accomplished in this case, even though Petitioner has offered some reliable evidence plus an experienced hepatologist to convey her causation opinion. CONCLUSION Petitioner has had her day in Court. I was present for all testimony offered therein. As I initially discerned, and as I now reiterate after a second review of the entirety of the record, she did not meet her burden of proof. Accordingly, because this claim has not been supported with sufficient preponderant evidence, Petitioner is not entitled to compensation. In the absence of a motion for review filed pursuant to RCFC Appendix B, the Clerk of the Court SHALL ENTER JUDGMENT in accordance with the terms of this Decision. 31 IT IS SO ORDERED. s/ Brian H. Corcoran Brian H. Corcoran Chief Special Master 31 Pursuant to Vaccine Rule 11(a), the parties may expedite entry of judgment if (jointly or separately) they file notices renouncing their right to seek review. 54 ================================================================================ DOCUMENT 5: USCOURTS-cofc-1_21-vv-01513-4 Date issued/filed: 2025-09-30 Pages: 58 Docket text: JUDGE VACCINE REPORTED OPINION (PUBLIC VERSION) (reissued for publication of 93 JUDGE VACCINE OPINION, dated September 18, 2025). Signed by Judge Eleni M. Roumel. (jmc) Service on parties made. -------------------------------------------------------------------------------- Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 1 of 58 In the United States Court of Federal Claims PORTIA EXUM, No. 21-1513 Petitioner, Filed Under Seal: September 18, 2025 v. Publication: September 30, SECRETARY OF HEALTH AND 20251 HUMAN SERVICES, Respondent. Amber D. Wilson of Wilson Science Law, Washington, D.C. argued for Petitioner. Mary Novakovic, of the United States Department of Justice, Civil Division, Washington, D.C., argued for Respondent. With her on the briefs were Brett A. Shumate, C. Salvatore D’Alessio, Heather L. Pearlman, and Alexis B. Babcock, of the United States Department of Justice, Civil Division, Washington, D.C. MEMORANDUM AND ORDER Petitioner Portia Exum seeks compensation under the National Vaccine Injury Compensation Program (Vaccine Act). 42 U.S.C. §§ 300aa-10 et seq., alleging that she suffers from autoimmune hepatitis (AIH) caused by the measles-mumps-rubella (MMR) and tetanus- diphtheria-acellular pertussis (Tdap) vaccines she received on August 20, 2018. This action has a lengthy history, a summary of which provides helpful context to the present dispute. Petitioner initially filed this action on June 25, 2021, and on August 29, 2024, the 1 On September 18, 2025, this Court issued a sealed version of this Memorandum and Order. ECF No. 93. The Court informed the parties that any proposed redactions were to be submitted by September 29, 2025. Id. at 58. Having received no proposed redactions from the parties, the sealed and public versions of this Memorandum and Order are identical except for the publication date and this footnote. Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 2 of 58 Chief Special Master denied Petitioner’s claim. ECF No. 1 (Petition or Pet.); ECF No. 74 (First Entitlement Decision). Subsequently, Petitioner moved this Court for review of the Chief Special Master’s decision. ECF No. 76. Subsequently, this Court granted Petitioner’s motion for review in part—remanding the action and instructing the Chief Special Master to provide a more fulsome explanation of his weighing of the record evidence. Exum v. Sec’y of Health & Hum. Servs., 175 Fed. Cl. 681 (2025) (Exum I); ECF No. 85. On May 27, 2025, the Chief Special Master issued a thorough and well-reasoned second entitlement decision, again denying Petitioner’s claim. ECF No. 88 (Remand Decision). Pending before the Court is Petitioner’s Motion for Review of the Chief Special Master’s second decision — the Remand Decision — denying her petition for compensation. ECF No. 87. The difficulties associated with Petitioner’s circumstances are not lost on this Court. Despite this, after repeated judicial consideration of the evidentiary record in her case, it is evident that Petitioner’s arguments do not provide a sufficient legal basis for setting aside the Chief Special Master’s Decision. The Chief Special Master thoroughly “considered the relevant evidence of record, dr[ew] plausible inferences and articulated a rational basis for the decision”— comprehensively analyzing the record evidence and law relevant to this case. Kirby v. Sec’y of Health & Hum. Servs., 997 F.3d 1378, 1381 (Fed. Cir. 2021) (alteration in original) (quoting Lampe v. Sec’y of Health & Hum. Servs., 219 F.3d 1357, 1360 (Fed. Cir. 2000)); Hines v. Sec’y of Health & Hum. Servs., 940 F.2d 1518, 1528 (Fed. Cir. 1991). Accordingly, and for the reasons described below, Petitioner’s Motion for Review is DENIED. BACKGROUND The Chief Special Master’s Remand Decision, his First Entitlement Decision, and this Court’s prior opinion contain thorough discussions of the evidence of record in this case, familiarity with which is presumed. ECF No. 88 (Second Entitlement Decision or Decision) at 2– 2 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 3 of 58 30; ECF No. 74 (First Entitlement Decision); Exum I, 175 Fed. Cl. 681.2 What follows is a summary of the aspects of the record pertinent to issues raised in Petitioner’s present Motion for Review. I. Factual Background A. Petitioner’s Pre-Vaccination Medical History Prior to the receiving the vaccines at issue in this case, Petitioner’s medical history included gastrointestinal issues and kidney stones. Pet. Ex. 2 (ECF No. 6-2) at 9–12; Pet. Ex. 3 (ECF No. 6-3) at 273–75. On August 17, 2018, in preparation for a trip to Kenya and Tanzania, Petitioner received an anti-malarial medication, which she was instructed to begin taking beginning two days before she visited high-risk areas and to continue taking until seven days after her departure from those high risk areas. Pet. Ex. 3 at 74; Pet. Ex. 4 at 8 (ECF No. 6-4). On August 20, 2018, she also received the Tdap and MMR vaccines. Pet. ¶ 4; Pet. Ex. 3 at 72; Pet. Ex. 11 (ECF No. 7-2) (Exum Aff.) ¶ 7. B. Petitioner’s AIH Symptom Onset3 Petitioner traveled to Kenya and Tanzania from August 29, 2018 through September 8, 2018, and reported four or five bug bites during the trip. Exum Aff. ¶ 8; Pet. Ex. 4 at 35. When she returned, Petitioner reported feeling “extreme fatigue,” and by mid-late September she had 2 Citations throughout this Memorandum and Order reference the ECF-assigned page numbers, which do not always correspond to the pagination within the document. 3 Petitioner’s AIH diagnosis is undisputed. See ECF No. 87 (Motion or MFR) at 6 (“It is undisputed that Mrs. Exum developed autoimmune hepatitis (AIH) . . . .”); ECF No. 72 at 15 (“Respondent does not contest petitioner’s diagnosis of [AIH].”). 3 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 4 of 58 developed gastroesophageal reflux disease (GERD) symptoms and indigestion. Pet. Ex. 3 at 57; Pet. Ex. 4 at 35. By October 2018, she was experiencing daily nausea. Pet. Ex. 4 at 35. On October 26, 2018—two months after receiving the Tdap and MMR vaccines—a routine physical revealed that Petitioner’s liver enzyme levels were abnormally high. Pet. ¶ 5; Exum Aff ¶ 11; Pet. Ex. 4 at 42, 44. Prior to this test, her liver enzyme levels had been normal. Specifically, testing performed during a visit to the Emergency Room (ER) on May 16, 2018— three months before receiving the vaccines at issue—indicated that Petitioner’s liver enzyme levels were normal. Pet. Ex. 3 at 268. Lab testing performed in July 2018 also revealed normal liver enzyme levels. Pet. ¶ 9; Pet. Ex. 1 (ECF No. 6-1) at 22. Petitioner visited a gastroenterologist on November 28, 2018, for reporting elevated liver enzyme levels, nausea, and gastrointestinal (GI) symptoms. Pet. Ex. 3 at 280–83. Her abdominal exam did not reveal any signs of liver enlargement or tenderness, although Petitioner reported that she was experiencing “right-sided distress.” Id. at 282. A physician’s assistant (PA) noted the “unclear etiology” of Petitioner’s condition, referred her to a hepatologist for an MRI of her liver, and recommended that Petitioner undergo H. pylori testing, repeat liver function tests, take Pepcid, and make several changes to her diet. Id. at 282−83. Those tests revealed that Petitioner’s liver enzyme levels were “extremely elevated”—even higher than her previous levels—but were negative for H. pylori. Id. at 67−69. On December 6, 2018, a gynecologist removed Petitioner’s inter-uterine device (IUD) to eliminate the IUD as a possible cause of her liver issues. Id. at 242–45. The following day, Petitioner visited her primary care physician (PCP), reporting epigastric pressure and discomfort (specifically on her right side), nausea, fatigue, and that her eyes appeared yellow. Pet ¶ 9; Pet. Ex. 3 at 61. Her abdominal exam revealed no enlargement of the liver or spleen, and her viral 4 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 5 of 58 hepatitis panel came back negative, but her liver enzyme levels—including aspartate aminotransferase (AST) and alanine aminotransferase (ALT)—and her ferritin levels were elevated. Pet. Ex. 3 at 62−65; Pet. Ex. 4 at 31−33. Petitioner’s PCP referred her to a hepatologist. Pet. Ex. 3 at 63. On December 11, 2018, Petitioner had an MRI of her liver. Pet. Ex. 4 at 28−30. The MRI revealed two hyper-intense lesions (abnormal growth of cells or tissue in the liver) and asymmetric dilation of the left renal vein. Id. Radiologists recommended that she see a hepatologist for the hepatic lesions. Id. at 28. Petitioner returned to her PCP on December 14, 2018. Pet. Ex. 3 at 57. He ordered liver enzyme testing, which again revealed abnormally high levels of AST and ALT but excluded the possibility of an active hepatitis infection. Id. at 57–58. Petitioner’s PCP also referred her to an infectious disease specialist. Id. at 59. On December 19, 2018, Petitioner was evaluated by a hepatologist, and the records associated with that visit noted that Petitioner had no signs of decompensated liver disease and that her abdominal exam did not reveal abnormalities. Id. at 232−38; id. at 235 (“GI/Abdomen: soft, nontender, nondistended, normoactive bowel sounds”); id. at 232–33 (“Patient has no evidence of decompensated liver disease . . . .”). Lab results indicated that her AST and ALT levels remained elevated but did not indicate acute liver failure or an active hepatitis infection. Id. at 232, 237; Pet. Ex. 8 (ECF No. 6-8), at 73. Petitioner represented that her lifestyle did not present risk factors for liver disease (e.g., drug use, blood transfusions), but acknowledged taking anti- malarial medication during her recent trip to Kenya and Tanzania. Pet. Ex. 3 at 232. She also reported that reishi mushrooms were the only other over-the-counter medication or supplement 5 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 6 of 58 she was taking. Id. The hepatologist recommended that Petitioner have a liver biopsy and another liver MRI in six months. Id. at 237. Petitioner had a liver biopsy on January 3, 2019, which showed moderate interface and lobular hepatitis. Id. at 229. The liver biopsy “raise[d] a broad differential diagnosis which includes but [was] not limited to” infections, AIH, hepatitis secondary to the effects of medications or supplements, and Wilson’s disease (a genetic disorder that causes copper build up in the body). Id. The following day, Petitioner was evaluated by a hematology specialist. Id. at 222. He concluded that this elevated level was due to “obvious liver disease, whose etiology is as yet unknown” and diagnosed her with hepatitis. Id.; Pet. Ex. 7 (ECF No. 6-7) at 29. A follow-up evaluation by an infectious disease specialist on January 24, 2019, confirmed that a diagnosis of AIH was most likely. Pet. Ex. 4 at 6−8, 12–13. During this visit, Petitioner discussed her 2018 international travel, including that she had swam in the Indian Ocean, incurred several insect bites, and felt extremely tired fatigue upon her return; the records from that visit also noted that Petitioner was taking a four- to six-week course of prednisone, which she had begun earlier in January 2019. Id. at 6, 8. Testing indicated that Petitioner had previously (at an undetermined time) had an Epstein-Barr viral infection (EBV) and also showed that her liver enzyme levels were improving but remained abnormally high. Id. at 12 (noting that Petitioner was “EBV positive but indicative of a previous infection, not a current infection”); Pet. Ex. 3 at 201−08. In January 2019, Petitioner was also treated for thrush and a kidney stone. Pet. Ex. 3 at 52; Pet. Ex. 2 at 32−36; Pet. Ex. 4 at 12. C. Petitioner’s Treatment for AIH During February and March 2019, Petitioner’s liver enzyme levels improved, but remained elevated. Pet. Ex. 3 at 42−51. She took azathioprine and prednisone for her liver issues. Id. at 197. In April 2019, when Petitioner returned to her PCP to discuss symptoms unrelated to her 6 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 7 of 58 AIH (throat, thrush, chest pains), her PCP indicated that Petitioner’s AIH was “improving.” Id. at 36−37. Petitioner also returned to her hepatologist, reporting similar symptoms. Pet. Ex. 10 (ECF No. 7-1) at 6. Her liver enzyme levels were improving but had not returned to normal. Pet. Ex. 3, at 195; Pet. Ex. 10 at 10–11. The hepatologist recommended increasing her dose of azathioprine and decreasing her dose of prednisone. Pet. Ex. 3 at 195; Pet. Ex. 10 at 10. On August 26, 2019, Petitioner again returned to her hepatologist. Pet. Ex. 3 at 162−65. Testing performed during that visit revealed that her liver enzyme levels were no longer improving and instead were elevated relative to previous levels.4 Id. at 165. Petitioner’s hepatologist instructed her to continue taking azathioprine and ordered a metabolite screen to confirm that Petitioner was not suffering from hepatoxicity. Id. Testing performed in September 2019 showed improved liver enzyme levels that were slightly elevated. Id. at 29. On January 27, 2020, Petitioner reported increased fatigue and myalgias, but her hepatologist noted that her liver enzyme levels had normalized, and that she had no evidence of decompensated liver disease. Pet. Ex. 10 at 56, 61. Nevertheless, Petitioner’s hepatologist instructed her to continue taking azathioprine and to have her liver serum enzymes tested every two to three months. Id. at 61. At a follow-up appointment six months later on July 27, 2020, Petitioner’s liver enzyme levels were normal. Pet. Ex. 3 at 154. She was advised to continue taking azathioprine until 18 months after her diagnosis, at which point she could stop taking the drug, assuming her liver biopsy did not indicate significant inflammation. Id. Other than a February 2021 liver biopsy which revealed “chronic hepatitis with minimal interface activity and mild portal fibrosis (stage 1 of 4),” 4 In an appointment with a nutritionist days later on August 30, 2019, the nutritionist noted that the increased liver enzyme levels correlated with Petitioner’s tapering off of her prednisone prescription. Pet. Ex. 3 at 32. 7 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 8 of 58 Plaintiff’s testing from mid-2020 through 2022 indicated normal liver enzyme levels. Pet. Ex. 14 (ECF No. 16-1) at 41; Pet. Ex. 15 (ECF No. 16-2) at 83, 149. A March 2022 hepatology visit did not indicate any signs of liver disease; her hepatologist noted that her liver function tests were stable and that she was not experiencing side effects related to her immunosuppression. Pet. Ex. 15 at 149; Pet. Ex. 14 at 36–41. As of November 2023, Plaintiff was not indicating any markers of liver disease. Pet. Ex. 46 (ECF No. 53-1) at 6–7. Petitioner indicates that she “has had to drastically change all of her prior nutrition and lifestyle habits due to suffering from a chronic illness” and that she “continues to require[] regular care and monitoring from specialized physicians for management of her autoimmune hepatitis and chronically elevated liver serum enzymes.” Pet. ¶¶ 20−21.5 II. Expert Opinions In addition to Petitioner’s medical records, the Chief Special Master reviewed four expert reports filed by three different experts: Dr. Robert Gish, Dr. Jeffrey Crippin, and Dr. Andrew MacGinnitie. See generally Pet. Ex. 16 (ECF No 18-1) (Gish Initial Report); Pet. Ex. 38 (ECF No. 28-1) (Gish Rebuttal Report); Resp. Ex. A (ECF No. 23-1) (Crippin Report); Resp. Ex. C (ECF No. 23-3) (MacGinnitie Report). All three experts testified at the Entitlement Hearing. See generally Entitlement Hearing Transcript, dated Mar. 7, 2024 (ECF No. 64) (Hr’g Tr.). A. Petitioner’s Expert 1. Dr. Robert Gish Dr. Gish is a clinical adjunct professor of medicine at the University of Nevada School of Medicine and University of California at San Diego Skaggs School of Pharmacy and 5 Paragraph 21 appears on page 4 of the Petition. The numbering of paragraphs restarts at one in the paragraph following paragraph 20. For clarity, paragraph references to the Petition continue numbering the paragraphs following paragraph 20 as 21 through 30. 8 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 9 of 58 Pharmaceutical Science and serves as the Medical Director of the Hepatitis B Foundation. Gish Initial Report at 1. He actively sees patients, consults with hepatology and liver centers nationwide, and performs clinical research. Id. at 1−2. Dr. Gish’s areas of expertise include internal medicine, gastroenterology, and hepatology. Id.; Hr’g Tr. at 91:11–15. Dr. Gish acknowledges that he does not identify as an immunologist. Hr’g Tr. at 91:11–15. He testified that approximately 10 of his patients in the past 30 years have developed AIH after receiving a vaccine. Hr’g Tr. 14:8–17. One of those cases involved the MMR vaccine, and none attributed AIH to the Tdap vaccine. Id. at 14:8–17, 89:5–90:10. Dr. Gish opined that “the pathogenesis of [Petitioner’s] AIH is more probable than not attributed to the administration of her multiple vaccine dosing.” Gish Initial Rep. at 8. Dr. Gish offered several theories supporting this opinion. He theorized that the vaccines could have caused Petitioner’s AIH through molecular mimicry (an antigen-specific mechanism) and through several other immune activation mechanisms. Id. at 18−22; see also Hr’g Tr. at 42:22−44:18. Dr. Gish posited that the live, attenuated measles virus in the MMR vaccine could have caused Petitioner to experience an autoimmune response resulting in AIH. Gish Initial Rep. at 18−20; Hr’g Tr. at 36:13−37:18. He relied on several studies in support of this theory, including an animal study indicating the specific immune cells that the measles vaccine targets (dendritic cells).6 Hr’g Tr. at 38:15−39:14; Pet. Ex. 33, Linda J. Rennick, et al., Live-Attenuated Measles Virus Vaccine Targets Dendritic Cells and Macrophages in Muscle of Nonhuman Primates, 89 J. Virology 2192 (2015) (ECF No. 19-9) (Rennick); Pet. Ex. 18, U. Christen & E. Hintermann, Pathogens and Autoimmune Hepatitis, 195 J. Clinical & Experimental Immunology 35 (2019) 6 Dr. Gish testified that he believed Rennick was relevant to the measles component of Petitioner’s causation theory, despite that it was performed in an animal model. Hr’g Tr. at 38:15–39:14. 9 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 10 of 58 (ECF No. 18-3) (Christen & Hintermann); Pet. Ex. 29, D.A. Robertson et. al., Persistent Measles Virus Genome in Autoimmune Chronic Active Hepatitis, The Lancet (1987) (ECF No. 19-5) (Robertson); see also Gish. Initial Rep. at 10−11, 19. Further, Dr. Gish relied on a study of ex vivo human T cells to support the proposition that wild-type measles infections and the attenuated measles vaccine cause immunosuppression. Hr’g Tr. at 40:21–42:21; Pet. Ex. 31, Ralph Nanan, et al., Measles Virus Infection Causes Transient Depletion of Activated T Cells From Peripheral Circulation, 12 J. Clinical Virology 201 (1999) (ECF No. 19-7) (Nanan); see also Pet. Ex. 32, Thomas Munyer et al., Depressed Lymphocyte Function After Measles-Mumps-Rubella Vaccination, 132 J. Infectious Diseases 75 (1975) (ECF No. 19-8); Gish Initial Report at 19. Dr. Gish testified that during this immunosuppressed state, the measles infection triggers measles-specific and “bystander” immune cells. Hr’g Tr. at 42:10– 21 (discussing Gish Initial Report at 19). Using this bystander activation theory, Dr. Gish theorized that Petitioner’s MMR vaccine (which includes a live, attenuated measles vaccine infection) could have caused immunosuppression, activating both measles-specific and non-measles-specific (“bystander”) immune cells.7 Id. at 46:12−49:11; 59:24−60:2. The activation of those immune cells caused a cross-reaction of T cells, which caused a breaking of Petitioner’s self-tolerance to hepatic autoantigens. Id. at 53:21−54:12; 58:7–59:20. That, in turn, caused an autoimmune reaction. Id. at 59:15–20. 7 On cross-examination, Dr. Gish addressed the apparently contradictory idea that suppression of the immune system can lead to AIH, a condition involving overactivation of the immune system. Hr’g Tr. at 112:7–113:10. He explained that the adaptive immune system compensates for the innate immune system, which activates a wide variety of cells, causing “off-target” effects that stimulate other parts of the immune system. Id. 10 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 11 of 58 According to Dr. Gish, the Tdap booster could have activated Petitioner’s memory T cells because she had previously received the tetanus and diphtheria vaccines, which “amplif[ied] a normal immune response.” Id. at 62:7–63:2; Gish Initial Report at 23; Gish Rebuttal Report at 6.; see also Gish Initial Report at 10 (citing Pet. Ex. 19, Christine S. Benn et al., A Small Jab – A Big Effect: Nonspecific Immunomodulation by Vaccines, 34 Trends in Immunology 431 (2013) (ECF No. 18-4) (Benn)). He also testified that because she had previously had the Hepatitis A vaccine, memory T cells from those vaccinations could also have been the bystander immune cells that triggered an amplified immune response, noting that “there is a strong suggestive data in the medical literature” that AIH patients suffer from abnormalities associated with their T regulatory cells. Hr’g Tr. at 64:15−65:18; see also Gish Initial Report at 22 (arguing that given her Tdap and MMR vaccines “were both booster vaccines, Mrs. Exum likely suffered a sufficient immune response to increase her risk of immune dysfunction and clinical expression of autoimmune hepatitis disease.”).8 Similarly, Dr. Gish theorized that Petitioner’s prior whole cell pertussis vaccine could have caused her to display “polarization to Th1 and Th17 responses” when administrated a booster vaccine, like Tdap, with an acellular pertussis component. Gish Initial Report at 21−22. Citing studies from 2018 and 2010, Dr. Gish explained that Th17 cells “induce inflammation and aid B cell production of antibodies” and “are believed to play an important role in the development of a variety of autoimmune diseases.” Id. (first citing Pet. Ex. 34, Ricardo da Silva Antunes et al., Th1/Th17 Polarization Persists Following Whole-Cell Pertussis Vaccination Despite Repeated Acellular Boosters, 128 J. Clinical Investigation 3853 (2018) (ECF No. 20-1) (Antunes); and then 8 See Pet. Ex. 3 at 72−73 (Petitioner’s vaccine history). As relevant here, Petitioner had previously received the DTP, Hepatitis A, Hepatitis B, MMR, Td, Tdap, Tetanus, and Yellow Fever vaccines. Id. 11 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 12 of 58 citing Pet. Ex. 35, Fouad Lafdil et al., Th17 Cells and Their Associated Cytokines in Liver Diseases, 7 Cellular & Molecular Immunology 250 (2010) (ECF No. (20-2) (Lafdil)).9 Dr. Gish stated that medical literature supported a causal connection between the MMR and Tdap vaccines and AIH and cited numerous case reports to support his theory. Hr’g Tr. at 27:22–25; Gish Rebuttal Report at 3; see Pet. Ex. 21, Walid R. Saliba & Mazen Elias, Acute Hepatitis Following MMR Vaccination, 16 Euro. J. Internal Med. 379 (2005) (ECF No. 18-6) (Saliba & Elias); Pet. Ex. 23, PA Berry & G Smith-Laing, Hepatitis A Vaccine Associated With Autoimmune Hepatitis, 13 World J. Gastroenterology 2238 (2007) (ECF No. 18-8) (Berry & Smith-Laing); Pet. Ex. 24, Ganesh R. Veerappan et al., Vaccination-Induced Autoimmune Hepatitis, 50 Digestive Diseases & Scis. 212 (2005) (ECF No. 58-1) (Veerappan); Pet. Ex. 25, Sruthi Kapliyil Subramanian, et al., Postinfectious Autoimmune Hepatitis-Induced Liver Failure: A Consequence of Hepatitis A Virus Infection, 7 ACG Case Reps. J. 1 (2020) (ECF No. 19-1) (Subramanian); Pet. Ex. 26, Marline A J van Gemeren, et al., Vaccine-Related Autoimmune Hepatitis: The Same Disease as Idiopathic Autoimmune Hepatitis? Two Clinical Reports and Review, 52 Scandinavian J. Gastroenterology 18 (2017) (ECF No. 19-2) (van Gemeren); Pet. Ex. 27, Ponni Perumalswami, et al., Vaccination as a Triggering Event for Autoimmune Hepatitis, 29 Seminars in Liver Disease 331 (2009) (ECF No. 61) (Perumalswami); Pet. Ex. 28, Tokio Sasaki, et al., Autoimmune Hepatitis Following Influenza Virus Vaccination, Medicine, July 2018 (ECF No. 19-4) (Sasaki); Pet. Ex. 30, Giorgina Mieli-Vergani, et al., Measles and Autoimmune Chronic Active Hepatitis, The Lancet, Sept. 16, 1989, at 688 (ECF No. 19-6) (Mieli-Vergani I); Pet. Ex. 9 In addition to the theories described above, Dr. Gish also theorized that the aluminum adjuvant in the Tdap vaccine could have caused Petitioner’s AIH. Gish Initial Rep. at 23. However, at the Entitlement Hearing, he expressly stated that he was “setting aside” that theory. Hr’g Tr. at 60:3−15. 12 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 13 of 58 45, Jorch, et al. (1984) (Jorch), cited in Institute of Medicine, Committee to Review Adverse Effects of Vaccines: Evidence and Causality 39–430 (Kathleen Stratton, et al., eds., 2012) (ECF No. 45- 3) (IOM). During cross-examination, however, Dr. Gish acknowledged that numerous case studies presented did not involve the MMR and Tdap vaccines. Hr’g Tr. at 97:14−107:22. ****Continued on next page**** 13 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 14 of 58 ECF No. Case Report Vaccine(s) Related Illness 18-6 Pet. Ex. 21, Saliba & Elias (2005) MMR Acute hepatitis10 Pet. Ex. 23, Berry & Smith-Laing Acute liver injury 18-8 Hepatitis A (2007) consistent w/ AIH Typhoid, Hepatitis A, Flu-like symptoms 58-1 Pet. Ex. 24, Veerappan (2005) Td, oral polio, MMR then AIH N/A; wild acute 19-1 Pet. Ex. 25, Subramanian (2020) AIH Hepatitis A infection Pet. Ex. 26, van Gemeren 19-2 Hepatitis A, Hepatitis B AIH (2017) Pet. Ex. 26, van Gemeren 19-2 Hepatitis A, Tdap AIH (2017) Hepatitis A and yellow 61 Pet. Ex. 27, Perumalswami (2009) AIH fever 19-4 Pet. Ex. 28, Sasaki (2018) Flu AIH Pet. Ex. 30, Mieli-Vergani I N/A; wild measles 19-6 AIH (1989) infection11 45-3 Pet. Ex. 45, Jorch, et al.12 MMR Meningoencephalitis 10 According to Dr. Gish’s testimony, the difference between acute hepatitis and AIH, which is chronic, is duration. Hr’g Tr. at 46:19−47:15. Acute hepatitis lasts less than six months, but chronic hepatitis persists for longer than six months. See id. at 100:18−101:3 (Dr. Gish explaining that chronic hepatitis means the patients has “documented elevated liver tests” for six months). Although the criteria for AIH was not published until 2008—several years after the Saliba & Elias report was published—the Saliba & Elias patient’s hepatitis fit the “acute” description because “the patient’s viral hepatitis testing was negative and spontaneously the liver function tests normalized after 4 weeks.” Gish Initial Report at 14. 11 The Mieli-Vergani I case report states that eight of the twelve child patients in this study “had received measles vaccination.” See Mieli-Vergani at 1. The study further states: “Our data show[s] that in children [Autoimmune Chronic Hepatitis] develops despite measles vaccination, and that they have low measles antibody titres raise questions about a causative link between measles and this autoimmune condition, at least in childhood.” Id. 12 This case report is mentioned in the excerpt of a publication by the Institute of Medicine filed by Petitioner as Exhibit 45. See Pet. Ex. 45, Institute of Medicine, Adverse Effects of Vaccines: Evidence and Causality (ECF No. 45-3). 14 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 15 of 58 Dr. Gish theorized that when multiple vaccines are administered at the same time, the combination of a “[g]enetic predisposition to the immune stimulation of hepatitis A” and an environmental trigger (e.g., multiple vaccines administered concomitantly, plus adjuvants) “can stimulate a very robust immune response that may not be able to be brought under control until [the patient] start[s] immunosuppressants.” 13 Hr’g Tr. at 62:10–22, 69:7–14. Dr. Gish concluded that this is “a very, very good . . . theory” as to what occurred in Petitioner’s case. Id. at 62:23– 63:2. Dr. Gish acknowledged, however, that no genetic testing done on Petitioner supported this proposition; instead, Dr. Gish based his theory, that Petitioner may have a genetic predisposition that made her susceptible to AIH, on the contention that this kind of genetic predisposition is common. Id. at 96:7−97:13 (Dr. Gish testifying that “very large studies, with thousands and thousands of patients . . . have found very powerful statistic[al] correlations with genetic diseases, genetic abnormalities, genetic mutations . . . and these different autoimmune diseases”). Dr. Gish’s Initial Report also stated that Petitioner’s AIH diagnosis was “medically certain,” based on Petitioner’s medical history, medical records, and the specific sequence of events that led to her AIH. Gish Initial Report 2−7. In support, Dr. Gish discussed Petitioner’s pre-vaccination medical history, noting that prior to the vaccine, she did not appear to have liver issues, nor did her history indicate any alternative cause (other than the vaccine) for her condition. Hr’g Tr. at 14:21–16:6. Specifically, he noted that her physical examinations did not indicate liver 13 To support his theory of genetic predisposition, Dr. Gish cited the Vento study, found in Subramanian, which followed family members of AIH patients to determine whether they would develop an AIH infection after developing a Hepatitis A infection. Because some individuals did develop AIH following this sequence of events, Dr. Gish asserted that this study supports the general idea that a “[g]enetic predisposition to the immune stimulation of hepatitis A” can contribute to AIH. Hr’g Tr. at 69:7–14. 15 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 16 of 58 issues; her liver panel testing was normal; no lifestyle factors creating a risk of liver disease were present; and she tested negative for Hepatitis B and C. Id. at 15:17–16:6; 19:13−22:22.14 At the Entitlement Hearing, Dr. Gish addressed potential alternative causes to Petitioner’s AIH, as raised by the Respondent’s experts. Dr. Gish noted that the specialists who had treated Petitioner at the Emory Travel Clinic “concluded that her travel history [did] not suggest an alternative infectious cause to her elevated liver enzymes.” Gish Rebuttal Report at 8 (citing Pet. Ex. 4 at 7). Dr. Gish acknowledged that Petitioner’s anti-malarial medication could be a risk factor for AIH, but asserted that the timing did not support a connection, and that antimalarial medications typically do not cause long-term or chronic autoimmune conditions. Hr’g Tr. at 22:9– 14; 82:11−86:25 (discussing Resp. Ex. A, Tab 10, Benedetta Terzoli Beretta-Piccoli et al., Atovaquone/Proguanil-Induced Autoimmune-Like Hepatitis, 1 Hepatology Commc’ns 293 (2017) (ECF No. 25-10) (Beretta-Piccoli)). Further, although Petitioner was taking other supplements, the fact that her liver enzyme levels did not normalize after she stopped taking the supplements suggested to Dr. Gish that they were not the cause of her liver issues. Id. at 80:9–81:12. Relatedly, since Petitioner ceased taking reishi mushroom supplements after she learned that her liver enzyme levels were elevated, and saw no change in her liver enzyme levels as a result, Dr. Gish posited that this, too, could be eliminated as a potential cause of her AIH. Id. at 80:9–81:8. Additionally, Dr. Gish characterized the possibility that Petitioner’s history of small intestinal bacterial overgrowth (SIBO) could have contributed to her AIH as very remote, because SIBO is associated with a different autoimmune condition. Id. at 94:6–23. Thus, according to Dr. Gish, by process 14 Dr. Gish also noted that Petitioner’s medical records showed no positive tests for the Epstein- Barr Virus (EBV); however, Dr. Crippin noted that Petitioner’s medical records did contain evidence of a prior EBV infection at an undetermined time. Hr’g Tr. 21:19–22:4; Crippin Report at 4; Pet. Ex. 3 at 207 (positive tests for EBV Viral Capsid Antigen IGG and EBV Nuclear Antibody). 16 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 17 of 58 of elimination Petitioner’s MMR and Tdap vaccines causally contributed to her AIH. Id. at 22:23−23:19. In addition, citing various studies including Rennick, Saliba & Elias, and Berry & Smith- Laing, Dr. Gish concluded that “[t]he sum of clinical evidence supports that a general acceptable timeframe to infer causation is when onset of symptoms occurs within one to five months of receipt of vaccination.” Gish Initial Report at 23−24; see also Pet. Ex. 22, McMahon et al., Measles Vaccine Virus RNA in Children More than 100 Days After Vaccination, 11 Viruses 636 (2019) (ECF No. 18-7) (reporting that measles vaccine virus RNA was detected in children more than 100 days after receiving a measles-containing vaccine). According to Dr. Gish, Petitioner’s case fit within a “general acceptable timeframe to infer causation” because Petitioner’s testing showed elevated liver enzymes 68 days post-vaccination and her AIH diagnosis was confirmed five months post-vaccination. Gish Initial Report at 24; see also Gish Rebuttal Report at 9−11. In sum, Dr. Gish’s “elevator pitch” of Petitioner’s case was that the vaccine administration; the timing of her symptom onset, within 10 weeks of vaccine administration; her laboratory tests, which indicated fluctuating liver enzyme levels in 2018 through 2019; and her liver biopsy, which was consistent with recent AIH onset, taken together, indicated that the MMR and Tdap vaccines more likely than not caused her AIH. Hr’g Tr. at 70:6–77:1, 81:25–82:9. While Dr. Gish testified that AIH needs an environmental trigger, he acknowledged that Petitioner’s AIH could have been idiopathic (i.e., had no identifiable cause), and noted that he only identifies a trigger in approximately half of his AIH cases. Id. at 52:9−15, 95:6–22. B. Respondent’s Experts 1. Dr. Jeffrey Crippin Respondent’s Expert, Dr. Jeffrey Crippin is the Marilyn Bornefield Chair in Gastrointestinal Research and Treatment, Professor of Medicine, Department of Medicine, 17 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 18 of 58 Division of Gastroenterology at the Washington University in St. Louis School of Medicine. Crippin Report at 1. He also serves as the Vice Chair for Clinical Programs for the Department of Medicine. Id. Dr. Crippin concluded that Petitioner’s diagnosis of autoimmune hepatitis was reasonable, but challenged Dr. Gish’s conclusion that Petitioner’s Tdap and MMR vaccines led to her AIH diagnosis. Id. at 3; Hr’g Tr. at 125:9–130:12. Dr. Crippin asserted that Dr. Gish failed to acknowledge the other factors in Petitioner’s medical history that could also cause AIH, including: (1) evidence that Petitioner previously (but at an undeterminable time) had an Epstein-Barr Virus; (2) that Petitioner could have had other potential viral infections transmitted by the bug bites during her travels (although her records did not include evidence of other infections); (3) that Petitioner took an anti-malarial medication, which is associated with AIH; (4) Petitioner’s history of SIBO; (5) Petitioner’s travel to foreign countries, which could have increased her exposure to new bacteria; (6) that Petitioner regularly took over-the-counter supplements, including mushroom extracts; and (7) that Petitioner was using an IUD. Hr’g Tr.at 125:9−130:12, 135:13–16. In sum, Dr. Crippin posited that “there are a number of factors” that could have led to Petitioner’s AIH diagnosis, and “the interaction of multiple factors, both genetic and environmental” could have caused her AIH. Crippin Report at 4−6.15 Dr. Crippin cited numerous case reports and studies in support of the potential alternative causes of Petitioner’s AIH. See Resp. Ex. A, Tab 4, Haoran Peng et al., Autoimmune Hepatitis Following Epstein-Barr Virus Infection: A Diagnostic Dilemma, British Med. J. (2019) (ECF No. 25-4) (case report concluding that AIH has a potential association with Epstein-Barr Virus 15 Dr. Gish conceded that “based on the case report and biological understanding of AIH pathology that other causal agents could be plausible.” Gish Rebuttal Report at 4. 18 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 19 of 58 infection); Resp. Ex A, Tab 5, Claudia Caglioti et al., Chikungunya Virus Infection: An Overview, 36 New Microbiologica 211 (2013) (ECF No. 25-5) (article describing mosquito-transmitted Chikungunya virus infection); Resp. Ex. A, Tab 6, MK Huntington et al., Emerging Vector-Borne Diseases, 7 Am. Fam. Physician 551 (2016) (ECF No. 25-6) (article describing mosquito-borne viral infections such as West Nile Virus, Chikungunya, Zika, Ehrlichiosis, Rickettsial, Dengue, Lyme Disease, Malaria); Resp. Ex. A, Tab 7, A. Arturo Leis et al., West Nile Virus Infection and Myasthenia Gravis, 49 Muscle & Nerve 26 (2013) (ECF No. 25-7) (retrospective case series associating the West Nile Virus with Myasthenia gravis, an autoimmune disease); Resp. Ex. A, Tab 8, P. Karagianni et al., West Nile Virus Infection Triggering Autoimmune Encephalitis: Pathophysiological and Therapeutic Implications, 207 Clinical Immunology 97 (2019) (ECF No. 25-8) (case report associating West Nile Virus with autoimmune encephalitis); Resp. Ex. A, Tab 9, Amir Tanay, Chikungunya Virus and Autoimmunity, 29 Current Op. in Rheumatology 389 (2017) (ECF No. 25-9) (Tanay) (study associating Chikungunya virus with inflammation and immune activation “not unlike those seen in rheumatoid arthritis,” or RA, which is an autoimmune disease); Beretta-Piccoli (case report associating anti-malarial drug Malarone (Atovaquone- Proguanil) with AIH16); Resp. Ex. A, Tab 11, Yusuke Kinashi & Koji Hase, Partners in Leaky Gut Syndrome: Intestinal Dysbiosis and Autoimmunity, 12 Frontiers in Immunology (2021) (ECF No. 25-11) (study discussing the connection between intestinal dysbiosis, leaky gut syndrome and 16 As Dr. Crippin explains in his Report, the case described in Beretta-Piccoli differed from Petitioner’s because the patient in the case report took Malarone (an anti-malarial drug) in conjunction with azithromycin, which caused jaundice and acute hepatitis, and her symptoms resolved in two weeks. Approximately a year later, the patient took Malarone again and developed AIH. See Crippin Report at 5. In other words, the patient developed AIH in response to re- administration of Malarone. However, the case report was similar to Petitioner’s case because the patient in the case report traveled to Tanzania and “need[ed] prolonged therapy with corticosteroids/prednisone.” Id. 19 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 20 of 58 autoimmune disease); Resp. Ex. A, Tab 12, Muhammed Yuksel et al., A Novel “Humanized Mouse” Model for Autoimmune Hepatitis and the Association of Gut Microbiota With Liver Inflammation, 62 Hepatology 1536 (2015) (ECF No. 25-12) (animal study finding that significant gut microbiota of mice with AIH was significantly different from mice without AIH17); Resp. Ex. A, Tab 13, Rui Lin et al., Abnormal Intestinal Permeability and Microbiota in Patients with Autoimmune Hepatitis, 8 Int’l J. Clinical & Experimental Pathology 5153 (2015) (ECF No. 25-13) (study associating leaky gut and microbiome imbalance with AIH); Resp. Ex. A, Tab 14, Francesca Motta et al., Mushrooms and Immunity, 117 J. Autoimmunity (2021) (ECF No. 25-14) (review of studies discussing biochemical changes induced by different mushroom compounds); Resp. Ex. A, Tab 15, Muthukumaran Jayachandran et al., A Critical Review on the Impacts of β-Glucans on Gut Microbiota and Human Health, 61 J. Nutritional Biochemistry 101 (2018) (ECF No. 25-15) (review summarizing in vitro, in vivo, and clinical studies on β-glucans and bacteria in gut microbiome); Resp. Ex. A, Tab 16, Mohamad O. Khawandanah et al., Autoimmune Hemolytic Anemia and Thrombocytopenia Attributed to an Intrauterine Contraceptive Device, 55 Transfusion 657 (2015) (ECF No. 25-16) (case report associating an IUD with Evans Syndrome manifested by autoimmune hemolytic anemia and thrombocytopenia). In addition, Dr. Crippin noted that AIH is often idiopathic, and that no case reports in published medical literature support that either the MMR or Tdap vaccines—independently or together—“trigger or are associated with [AIH].” Crippin Report at 3−4, 6; Hr’g Tr. at 130:3–12, 133:7–16, 137:3−13, 140:22–141:5. He explained that the MMR vaccine has been associated with idiopathic/immune thrombocytopenia and arthritis in children, and joint pain and inflammation, 17 Dr. Crippin noted in his Report that “a causative relationship was thought to deserve further investigation.” Crippin Report at 5. 20 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 21 of 58 but it is “is not clear” whether that is RA. Crippin Rep. at 6 (citing Resp. Ex. A, Tab 17, U Nieminen, et al., Acute Thrombocytopenic Purpura Following Measles, Mumps, and Rubella Vaccination. A Report on 23 Patients, 82 Acta Paediatr 267 (1993) (ECF No. 25-17)); Resp. Ex. A, Tab 18, C M Benjamin et al., Joint and Limb Symptoms in Children After Immunisation with Measles, Mumps, and Rubella Vaccine, 304 British Med. J. 1075 (1992) (ECF No. 25-18)). Further, case reports associated the Tdap vaccine with joint and muscle pain, a skin rash, and type 1 diabetes. Crippin Rep. at 6 (citing Resp. Ex. A, Tab 19, N. Ruhrman-Shahar et al., Autoimmune Reaction After Anti-Tetanus Vaccination—Description of Four Cases and Review of the Literature, 65 Immunological Rsch. 157 (2017) (ECF No. 25-19)). In his report and at the Entitlement Hearing, Dr. Crippin distinguished Petitioner’s case from the Saliba & Elias study. Crippin Report at 4 (citing Saliba & Elias). Dr. Crippin noted several key differences between Petitioner’s case and the patient in Saliba & Elias, including that the patient in Saliba & Elias suffered from acute hepatitis as opposed to AIH, and no liver biopsy was performed; the patient in Saliba & Elias had recently given birth, and pregnancy can cause immune suppression; and the patient in Saliba & Elias developed symptoms of her liver condition within two weeks after vaccination, whereas Petitioner’s symptom onset occurred around six to eight weeks. Hr’g Tr. 130:22−132:21. 2. Dr. Andrew MacGinnitie Respondent’s Second Expert, Dr. Andrew MacGinnitie is an Attending Physician as well as the Clinical Chief for the Division of Immunology at Boston Children’s Hospital overseeing clinical operations for Allergy/Immunology, Rheumatology and Dermatology, and is also an Associate Professor of Pediatrics at Harvard Medical School. MacGinnitie Report at 1. In his view, Petitioner’s AIH was “unrelated to” her MMR and Tdap vaccinations, and Dr. Gish’s theory was unreliable. Id. at 12; Hr’g Tr. at 148:4–10. 21 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 22 of 58 Dr. MacGinnitie asserted that the case reports cited by Dr. Gish failed to establish causality between MMR, Tdap, and AIH. Hr’g Tr. at 149:17–156:18; MacGinnitie Report at 6−7. Dr. MacGinnitie noted that AIH can occur after vaccination “by coincidence.” MacGinnitie Report at 6−7 (noting that case reports and case series “don’t consider factors such as the total number of individuals receiving the vaccine or the background rate of AIH in the population, making any assessment of causality impossible”). He further asserts that, given the widespread nature of vaccination and because vaccines are recommend for patients with AIH, the cases Dr. Gish cited were “likely coincidental.” Id. at 6–7, 11; Hr’g Tr. at 155:11–20. Further, Dr. MacGinnitie opined that case reports in general are “unable to really provide evidence of causation.” Hr’g Tr. at 150:2– 3. Further, Dr. MacGinnitie challenged Dr. Gish’s molecular mimicry theory, because Dr. Gish had not identified a potential homology between the MMR and Tdap vaccines and liver antigens. MacGinnitie Report at 7 (citing Resp. Ex. C, Tab 2, Institute of Medicine, Committee to Review Adverse Effects of Vaccines: Evidence and Causality (Kathleen Stratton, et al., eds., 2012) (ECF No. 26-2))18; Hr’g Tr. at 156:4–18, 157:22–158:7. Dr. MacGinnitie also contended that Dr. Gish had failed to explain how either vaccine otherwise could have caused Petitioner’s AIH. MacGinnitie Report at 7−11. Dr. MacGinnitie further contends that the bystander activation theory, that Dr. Gish opined would cause the relevant cross-reaction, is “ not a commonly accepted mechanism of [AIH].” Hr’g Tr. at 160:11–20. With respect to Dr. Gish’s theories relating to the measles virus, Dr. MacGinnitie countered that the “[m]easles virus causes profound suppression which is not seen with vaccination.” 18 This is a different portion of the same IOM publication cited by Petitioner. See Pet. Ex. 45, IOM. 22 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 23 of 58 MacGinnitie Report at 8−9 (emphasis omitted); Hr’g Tr. at 162:6–20. Although Dr. MacGinnitie agreed that the wild measles virus causes immunosuppression, he took issue with Dr. Gish’s position that the measles vaccine causes immune suppression. MacGinnitie Report at 8. Contrary to Dr. Gish’s assertion that “it is well understood” the measles vaccine induces temporary immunosuppression, Dr. MacGinnitie opined that “more contemporary literature stress[es] the need for measles vaccination to prevent the immunosuppression triggered by wild-type infection.” Id. (emphasis added). Dr. MacGinnitie noted that the Nanan and Munyer articles on which Dr. Gish relied did not provide “clinically meaningful” evidence and were outdated, having been published in 1999 and 1975, respectively. Id. Instead, Dr. MacGinnitie cited a 2017 study which stated that measles vaccination prevents measles infection, thereby “prevent[ing] measles- associated short- and long-term immunomodulating effects.” Id. (citing Resp. Ex. C, Tab 3, Michael J. Mina, Measles, Immune Suppression and Vaccination: Direct and Indirect Nonspecific Vaccine Benefits, 74 J. Infection S10 (2017) (ECF No. 26-3)). The Mina study also posited generally that the MMR vaccine can protect against other diseases by stimulating the immune system. Id.; see also Resp. Ex. C, Tab 4, Measles, Committee on Infectious Disease, Red Book (2021) (ECF No. 26-4). Dr. MacGinnitie also noted the apparent contradiction of Dr. Gish’s theory that measles infections and potentially also measles vaccinations lead to autoimmune suppression. MacGinnitie Report at 8–9; Hr’g Tr. at 162:15−20. Dr. MacGinnitie concluded that since AIH is an autoimmune condition—an overactivation of the immune system—any immunosuppression triggered by MMR would likely be “protective against development of AIH.” MacGinnitie Report at 7−8; Hr’g Tr. at 162:15−20. Further, Dr. MacGinnitie contended that it was unlikely that the activation of Petitioner’s memory T cells from her prior vaccines would cause autoimmune disease. Hr’g Tr. at 189:25– 23 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 24 of 58 191:7. Similarly, Dr. MacGinnitie rejected Dr. Gish’s Th17 theory, taking issue with his interpretation of the Antunes study. Id. at 170:14–173:24; MacGinnitie Report at 9−10. Dr. MacGinnitie also asserted that Dr. Gish failed to provide any evidence that Th17 disease would cause AIH; rather, the studies he cites simply listed Th17 as “one of many potential pathways toward development of AIH” and as Th17 cells are “found in healthy humans,” his Th17 theory was not a sufficient explanation for development of autoimmunity. MacGinnitie Report at 9−10 (citing Resp. Ex. C, Tab 10, S.A. Khader et al., Th17 Cells at the Crossroads of Innate and Adaptive Immunity Against Infectious Diseases at the Mucosa, 2 Mucosal Immunology 403 (Sept. 2009) (ECF No. 26-10)).19 Dr. MacGinnitie also took issue with Dr. Gish’s position that the timing of the onset of Petitioner’s AIH supported her causal theory. Dr. MacGinnitie contends that Dr. Gish failed to support his assertion that symptom onset within one to five months of vaccination is generally acceptable to infer causation. MacGinnitie Report at 11; Hr’g Tr. at 173:25–174:25. Further, Dr. MacGinnitie asserted that onset of autoimmune diseases tends to occur weeks—not months—after infection or immunization. MacGinnitie Report at 11 (first citing Resp. Ex. C, Tab 16, Jonathon R. Carapetis, Acute Rheumatic Fever and Rheumatic Heart Disease, 2 Nature Reviews: Disease Primers (Jan. 2016) (ECF No. 26-16); and then citing Resp. Ex. C, Tab 17, Shaheen Sombans et al., A Case Report of Acute Rheumatic Fever and a Brief Review of the Literature, Archives of Medical Science: Atherosclerotic Diseases (2018) (ECF No. 26-17)). Analogizing to a study he cited involving Guillain-Barré syndrome, Dr. MacGinnitie testified that he considers six weeks to be “the outer limit of what [he] would expect for a vaccine-triggered autoimmune injury.” Hr’g 19 Dr. MacGinnitie also rejected Dr. Gish’s aluminum adjuvant theory, which Dr. Gish had “set[] aside” at the Entitlement Hearing. See supra note 9. 24 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 25 of 58 Tr. at 175:11−176:8 (discussing Resp. Ex. C, Tab 19, Thomas J. Safranek et al., Reassessment of the Association between Guillain-Barre Syndrome and Receipt of Swine Influenza Vaccine in 1976-1977: Results of a Two-State Study, 133 Am. J. Epidemiology (1991) (ECF No. 26-19)). To that end, Dr. MacGinnitie pointed out that in the case reports Dr. Gish cited, the onset of AIH occurred within one month (and often sooner) of the relevant vaccination. Id. at 173:25–174:25 Dr. MacGinnitie also opined, that vaccines are generally only “a minor immune stimulus.” MacGinnitie Report at 10−11. He noted that vaccines are recommended for patients with AIH. Id. at 11. Such a recommendation, he contends, would be illogical if vaccines “were generally believed to play a role in triggering AIH.” Id. He also noted that none of Petitioner’s doctors— in particular the hepatologist who treated her AIH—associated her AIH with her MMR and Tdap vaccines. Id. at 12. II. Procedural Background As noted, on June 25, 2021, Petitioner filed a Petition for Compensation under the National Childhood Vaccine Injury Act (Vaccine Act), 42 U.S.C. §§ 300aa-10 et seq., alleging an off-Table injury. See Pet. Specifically, Petitioner alleged that the measles-mumps-rubella (MMR) and tetanus-diphtheria-acellular pertussis (Tdap) vaccines she had received on August 20, 2018, caused her autoimmune hepatitis (AIH) and chronically elevated liver serum enzymes. Id. ¶¶ 4, 21−22. As noted, in support of her claim Petitioner filed expert reports,20 medical literature,21 and medical 20 Pet. Ex. 16 (ECF No 18-1) (Gish Initial Report); Pet. Ex. 38 (ECF No. 28-1) (Gish Rebuttal Report). 21 Pet. Exs. 17−23 (ECF Nos. 18-2−18-8); Pet. Exs. 25−26, 28−33 (ECF Nos. 19-1−19-2, 19-4−19- 9); Pet. Exs. 34−35 (ECF No. 20-1−20-3); Pet. Ex. 24 (ECF No. 58-1); Pet. Ex. 27; (ECF No. 61- 1). 25 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 26 of 58 records.22 Respondent filed competing expert reports23 and medical literature24 in support of its contention that Petitioner had not established that her illness was caused by the MMR and Tdap vaccines. On March 7, 2024, Chief Special Master Brian H. Corcoran held an Entitlement Hearing, during which Drs. Robert Gish, Jeffrey Crippin, and Andrew MacGinnitie testified. See generally Hr’g Tr. Subsequently, on August 29, 2024, the Chief Special Master denied Petitioner’s claim, concluding that she had failed to prove her off-Table claim. ECF No. 74 (First Entitlement Decision); see Exum v. Sec’y of Health & Hum. Servs., No. 21-1513, 2024 WL 4291116 (Fed. Cl. Aug. 29, 2024). A. Petitioner’s First Motion for Review Petitioner next moved this Court for review of the Chief Special Master’s Decision, arguing that the Chief Special Master had erred by (i) articulating and applying an erroneous legal standard for Althen prong one, (ii) reaching conclusions on Althen prong two that were contrary to law, and (iii) failing to analyze Althen prong three.25 ECF No. 76 at 5. The Court conducted oral argument on Petitioner’s motion on December 19, 2024. ECF No. 81 (First OA Tr.) at 1; see also Minute 22 Petitioner filed her medical records as Exhibits 1−10. See ECF Nos. 6−7. Petitioner filed a Statement of Completion on June 30, 2021, confirming the submission of all medical records required by 42 U.S.C. § 11(c). ECF No. 8. She later filed additional medical records marked as Exhibits 14−15 (ECF No. 16-1−16-2) and Exhibit 46 (ECF No. 53). She also filed updated medical records as Exhibits 43–44 (ECF No. 45-1−45-2). 23 Resp. Ex. A (ECF No. 23-1) (Crippin Report); Resp. Ex. C (ECF No. 23-3) (MacGinnitie Report). 24 Exhibit A, Tabs 1−19 (ECF Nos. 25-1–25-19); Exhibit C, Tabs 1−19 (ECF Nos. 26-1–26-19). 25 The “Althen prongs” refer to the three-pronged causation standard for off-Table claims set forth in Althen v. Secretary of Health & Human Services, explained in further detail below. 418 F.3d 1274 (2005); see infra Discussion. 26 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 27 of 58 Entry, dated Dec. 19, 2024. Upon review, this Court granted Petitioner’s motion in part and vacated the Chief Special Master’s decision, remanding the case back to the Chief Special Master with specific instructions. Exum I, 175 Fed. Cl. at 687. First, the Court instructed that, on remand, the Chief Special Master should provide a more fulsome explanation of his rationales for accepting or rejecting Petitioner’s evidence as to prong one. Id. at 707–08. Second, the Court instructed the Chief Special Master to revise his findings on prong two, “only to the extent that his prong one analysis on remand affects those findings” and “insofar as he improperly required Petitioner to ‘persuasively limit or exclude all [alternative causes],’” and to “fully describe his rationale for all of his prong two conclusions in the remand decision.” Id. at 710. Third, this Court concluded that the Chief Special Master had properly declined to consider Althen prong three, and that he should only consider Althen prong three on remand if his analysis “of Althen prong one and prong two lead to a conclusion that Petitioner satisfied each of those prongs.” Id. at 711. B. The Remand Decision On May 27, 2025, the Chief Special Master issued his decision on remand, again denying Petitioner’s claim. ECF No. 88 (Remand Decision or Decision).26 Before proceeding to his analysis, the Chief Special Master recounted the medical facts relevant to Petitioner’s claim, thoroughly summarized the parties’ experts’ testimony at the Entitlement Hearing, and summarized every item of medical literature filed by Petitioner. Id. at 2−30. 26 The Chief Special Master issued the Remand Decision on May 27, 2025. ECF No. 86. Pursuant to Rule 18(b) of Appendix B of the Rules of the Court of Federal Claims (Vaccine Rules), the Chief Special Master provided the parties 14 days to identify and move to redact medical or other information, “the disclosure of which would constitute an unwarranted invasion of privacy.” Id. at 1 n.1; Vaccine Rule 18(b)(2). As neither party moved to redact any information, the Chief Special Master publicly reissued the Decision on July 8, 2025. ECF No. 88. For clarity and consistency, all references to the Chief Special Master’s Decision are to the public version, docketed as ECF No. 88. 27 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 28 of 58 The Chief Special Master was similarly thorough in each step of his analysis. First, the Chief Special Master noted that within the Vaccine Program, “the trend seems to be against” causally attributing AIH to covered vaccines. Id. at 38 (citing Porter v. Sec’y of Health & Hum. Servs., 663 F.3d 1242 (Fed. Cir. 2011)). He explained that the evidence filed in this case, too, did “not appear to embrace the concept that vaccines might in rare cases cause [AIH].” Id. The Chief Special Master further noted that most AIH-related claims within the Vaccine Program involved the hepatitis A and hepatitis B vaccines, and that there “are comparatively fewer cases involving the MMR or Tdap vaccines”—the vaccines at issue in this case—and the cases that do “are not favorable to Petitioner.” Id. (citing Rivas v. Sec’y of Health & Hum. Servs., No. 21-1683V, 2025 WL 551570, at *2 (Fed. Cl. Spec. Mstr. Jan. 24, 2025)). Second, the Chief Special Master held that Petitioner had failed to carry her burden to establish causation—again concluding that she failed to satisfy Althen prongs one and two. Id. at 38−39. With respect to prong one, the Chief Special Master first took care to note that some aspects of Petitioner’s theory “are wholly noncontroversial,” but that her theory “in its totality lacks sufficient preponderant support.” Id. at 39. He then proceeded to explain the underlying rationales supporting this conclusion: (1) Petitioner had not preponderantly demonstrated a link between the measles component of the MMR vaccine and AIH; (2) Evidence of a causal connection between the Tdap vaccine and AIH was weak or lacking; (3) Insufficient evidence was offered to establish the risk of receiving two vaccines at once; (4) Dr. Gish’s molecular mimicry mechanism for driving AIH due to vaccination was inadequately corroborated; (5) Case reports are weak causation evidence, and those offered were largely unhelpful to Petitioner; 28 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 29 of 58 (6) Other proposed mechanisms were inadequately developed; and (7) Respondent’s experts were more persuasive than Dr. Gish on the question of vaccine causation. Id. at 39−48 (citation modified). For all of those detailed reasons, the Chief Special Master concluded that Petitioner had not established that the Tdap vaccine and MMR vaccines, individually or together, can likely cause autoimmune hepatitis. Id. at 48. Likewise, with respect to prong two, the Chief Special Master concluded that Petitioner had not carried her burden to show that the MMR and Tdap vaccines she received “did cause” her AIH. Id. at 48−51 (quoting Boatmon v. Sec’y of Health & Hum. Servs., 941 F.3d 1351, 1355 (Fed. Cir. 2019)). In particular, he noted that “Petitioner’s medical records contemporaneous to her vaccination date are devoid of evidence that she experienced any close-in-time vaccine reaction.” Id. at 48. Additionally, the Chief Special Master noted that Petitioner had never tested positive for inflammation biomarkers which could indicate that she was experiencing an inflammatory event prior to her elevated liver test values. Id. Further, Petitioner was not experiencing an active measles infection, a hepatitis infection, or any other kind of infection that would occur “in the wake of the alleged measles vaccine-caused immune suppression.” Id. The Chief Special Master also noted that he had not identified in the medical records any instances of her treating physicians attributing her AIH to the MMR and Tdap vaccines. Id. Accordingly, the Chief Special Master reasoned that, absent that factual support, “[w]hat remains is the fact that Petitioner experienced some post-travel nonspecific symptoms which did not immediately merit treatment (and which arguably were consistent with her pre-vaccination health).” Id. And even to the extent those non- specific symptoms, such as fatigue, could be considered related to her AIH, the Chief Special Master concluded that this evidence was not a sufficient basis to connect the vaccines and Petitioner’s AIH. Id. at 48–49. The Chief Special Master also noted the presence of several risk 29 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 30 of 58 factors for AIH in Petitioner’s medical history, including her recent foreign travel, and that she took anti-malarial medications and other supplements. Id. at 49. Regarding Petitioner’s anti- malarial medication specifically, the Chief Special Master noted that there was not enough evidence to conclude that this was the cause of Petitioner’s AIH, but that it was “clearly something that had a demonstrated capacity to increase Petitioner’s possible hepatitis risk, and she received it after vaccination (and hence closer in time to her possible onset).” Id. at 49–50. The Chief Special Master concluded that there are “simply too many confounding factors specific to Petitioner’s experiences in the six-to-eight week post-vaccination period” to conclude that it is more likely than not that the vaccines caused her AIH. Id. at 51 (“The medical record simply does not contain sufficient facts suggesting the vaccines had anything to do with Petitioner’s disease.”). With respect to prong three, the Chief Special Master concluded that, although it was unclear precisely when the onset of Petitioner’s AIH occurred, she experienced “some clinical features of early AIH within six to eight weeks of vaccination, later corroborated by the LFT test results, and progressing to more concerning symptoms that led her to seek treatment in December,” and that this aligned with Dr. Gish’s theory. Id. at 52. The Chief Special Master noted that Dr. MacGinnitie agreed that the six- to eight-week time frame would have been medically possible, and that Petitioner’s treating physicians seemed to believe that her overall course “reflected a single disease process.” Id. The Chief Special Master concluded that, had he found that Petitioner carried her burden under prong one, he would have been able to conclude that this six- to eight- week time period for onset would be medically acceptable—satisfying prong three. Id. However, the Chief Special Master concluded that this ultimately “d[id] not matter,” given that he did not find prong one had been met. Id. 30 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 31 of 58 Third and finally, in closing, the Chief Special Master explained how the preponderance standard applies in claims brought under the Vaccine Act. Id. at 52–54. Specifically, “[w]hat matters is the individual reliability of the items of evidence offered, coupled with how well each item knits together into an overall theory that does not amount to speculation or unreasonable extrapolation.” Id. at 53. The Chief Special Master concluded by noting that here, “a preponderant evidentiary showing has not been made—and it was not a close case.” Id. C. Petitioner’s Second Motion for Review On June 26, 2025, Petitioner filed a second Motion for Review, this time seeking review of the Chief Special Master’s Remand Decision. ECF No. 87 (Motion or MFR). Petitioner raises two objections to the Remand Decision. Id. at 5–6. First, that the Chief Special Master’s assessment of Petitioner’s medical literature evidence as to Althen prong one constitutes legal error. Id. Second, that the Chief Special Master’s conclusions as to Althen prong two were contrary to law. Id. at 6. On July 28, 2025, Respondent filed its Response to Petitioner’s Motion, contending that Petitioner “has not shown that the Chief Special Master’s denial of entitlement was arbitrary, capricious, an abuse of discretion, or not in accordance with law,” and that this Court should affirm the Chief Special Master’s Decision. ECF No. 89 (Response or Resp.). Petitioner requested a hearing on her second Motion for Review, and accordingly, on September 8, 2025, this Court conducted oral argument. See ECF No. 92 (OA Tr.) at 1; see also Minute Entry, dated Sept. 8, 2025; MFR at 24. Petitioner’s Motion is now fully briefed and ripe for resolution. STANDARD OF REVIEW Pursuant to 42 U.S.C. § 300aa-12(e)(2), when ruling on a Motion for Review, this Court may: (A) uphold the findings of fact and conclusions of law of the special master and sustain the special master’s decision, 31 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 32 of 58 (B) set aside any findings of fact or conclusion of law of the special master found to be arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law and issue its own findings of fact and conclusions of law, or (C) remand the petition to the special master for further action in accordance with the court’s direction. 42 U.S.C. § 300aa-12(e)(2). This Court reviews a special master’s factual determinations under the arbitrary and capricious standard; legal questions under the “not in accordance with law” standard; and any discretionary rulings under the abuse of discretion standard. Munn v. Sec’y of Health & Hum. Servs., 970 F.2d 863, 870 & n.10 (Fed. Cir. 1992); see also Cerrone v. Sec’y of Health & Hum. Servs., 146 F.4th 1113, 1119 (Fed. Cir. 2025) (“In Vaccine Act cases, the Court of Federal Claims reviews the factual findings of the special master under the arbitrary and capricious standard and reviews the legal rulings of the special master to determine whether they are in accordance with law.”). The scope of this Court’s review is “uniquely deferential.” Milik v. Sec’y of Health & Hum. Servs., 822 F.3d 1367, 1376 (Fed. Cir. 2016) (quoting Hodges v. Sec’y of Health & Hum. Servs., 9 F.3d 958, 961 (Fed. Cir. 1993)). This Court is required to uphold the factual findings of a special master unless those findings are arbitrary or capricious. Lampe, 219 F.3d at 1360 (noting that, with respect to factual findings—particularly the “decision to credit the evidence”—“judicial review of the special master’s decision is very limited”); Munn, 970 F.2d at 870 & n.10 (noting that the arbitrary and capricious standard is “well understood to be the most deferential possible”). “The Vaccine Act makes clear that [the Court] do[es] not ‘second guess’ the special master’s fact-intensive conclusions that are ‘based upon [his] accumulated expertise in the field.’” Hinton v. Sec’y of Health & Hum. Servs., No. 23-2161, 2025 WL 763153, at *2 (Fed. Cir. Mar. 11, 2025) (quoting Hodges, 9 F.3d at 961). It is not this Court’s role to “reweigh the factual evidence, assess whether the special master correctly evaluated the evidence, or examine the 32 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 33 of 58 probative value of the evidence or the credibility of the witnesses—these are all matters within the purview of the fact finder.” Porter v. Sec’y of Health & Hum. Servs., 663 F.3d 1242, 1249 (Fed. Cir. 2011); see also Burns v. Sec’y of Health & Hum. Servs., 3 F.3d 415, 417 (Fed. Cir. 1993) (noting that a special master has discretion to determine the relative weight of the evidence, including medical records). If the special master’s conclusion is “based on evidence in the record that [is] not wholly implausible,” this Court is “compelled to uphold that finding as not being arbitrary or capricious.” Cedillo v. Sec’y of Health & Hum. Servs., 617 F.3d 1328, 1338 (Fed. Cir. 2010) (alteration in original) (quoting Lampe, 219 F.3d at 1363). “[R]eversible error is extremely difficult to demonstrate if the special master has considered the relevant evidence of record, drawn plausible inferences and articulated a rational basis for the decision.” Kirby v. Sec’y of Health & Hum. Servs., 997 F.3d 1378, 1381 (Fed. Cir. 2021) (alteration in original) (quoting Lampe, 219 F.3d at 1360); Hines v. Sec’y of Health & Hum. Servs., 940 F.2d 1518, 1528 (Fed. Cir. 1991). DISCUSSION Congress enacted the Vaccine Act to compensate parties presumed or proven to be injured by certain vaccines. 42 U.S.C. § 300aa–10 et seq. The Program was designed to “lessen the number of lawsuits against manufacturers and provide relative certainty and generosity of compensation awards in order to satisfy petitioners in a fair, expeditious, and generous manner.” Cloer v. Sec’y of Health & Hum. Servs., 654 F.3d 1322, 1325–26 (Fed. Cir. 2011) (en banc) (citation modified); see also K.G. v. Sec’y of Health & Hum. Servs., 951 F.3d 1374, 1380 (Fed. Cir. 2020) (citing Cloer, 654 F.3d at 1325) (“The Vaccine Act is a pro-claimant regime meant to allow injured individuals a fair and fast path to compensation . . . .”). The Vaccine Act grants jurisdiction to the Court of Federal Claims and the Office of Special Masters “over proceedings to determine if a petitioner . . . is entitled to compensation under the Program” for vaccine-related injuries or deaths and the amount of compensation owed. 42 33 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 34 of 58 U.S.C. § 300aa–12(a). Petitions alleging injuries are initially reviewed by a Special Master, who issues a decision on the petition. Bruesewitz v. Wyeth LLC, 562 U.S. 223, 228 (2011) (citing 42 U.S.C. §§ 300aa–11(a)(1), 300aa−12(d)(3)). To obtain compensation under the Vaccine Act, a petitioner must prove that a vaccine caused an injury. Althen v. Sec’y of Health & Hum. Servs., 418 F.3d 1274, 1278 (Fed. Cir. 2005). There are two ways for a petitioner to do this: (1) by proving that he suffered a Table injury within the specified time window after vaccination—in which case, causation is presumed (a Table claim), or (2) by proving causation-in-fact (an off-Table claim). de Bazan, 539 F.3d at 1351. Table claims are based on “a statutorily-prescribed presumption of causation” created by the Vaccine Injury Table. Althen, 418 F.3d at 1278; 42 U.S.C. § 300aa-14(a) (Vaccine Injury Table); 42 CFR § 100.3 (current Vaccine Injury Table). The Table identifies vaccines covered under the Vaccine Act, compensable injuries, and how soon after vaccination the first symptom or manifestation of onset must occur for purposes of receiving compensation. Bruesewitz, 562 U.S. at 228. If a petitioner can prove by a preponderance of the evidence that his injury meets the criteria in the Table, he has successfully made a Table claim and is “prima facie entitled to compensation.” Id.; de Bazan, 539 F.3d at 1351. In other words, “[b]ring the case within the timetable and specifications of a Table Injury and the statute does the heavy lifting—causation is conclusively presumed.” Hodges, 9 F.3d at 961. Alternatively, where the petitioner alleges an off-Table claim—i.e., claiming an injury not listed in the Vaccine Injury Table, or which first appears outside of the time limits set by the Table—“the heavy lifting must be done by the petitioner” to prove causation-in-fact. 42 U.S.C. § 300aa-11(c)(1)(C)(ii); Hodges, 9 F.3d at 961; Althen, 418 F.3d at 1278. This burden “is heavy indeed.” Hodges, 9 F.3d at 961. To prove causation for such an off-Table claim, a petitioner must 34 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 35 of 58 prove by a preponderance of the evidence that his vaccine was “not only a but-for cause of the injury but also a substantial factor in bringing about the injury.” Shyface v. Sec’y of Health & Hum. Servs., 165 F.3d 1344, 1352 (Fed. Cir. 1999). To make this showing, a petitioner must prove each of the three Althen prongs by a preponderance of the evidence: (1) a medical theory causally connecting the vaccination and the injury; (2) a logical sequence of cause and effect showing that the vaccination was the reason for the injury; and (3) a showing of a proximate temporal relationship between vaccination and injury. Althen, 418 F.3d at 1278; Boatmon, 941 F.3d at 1354–55 (quoting Moberly v. Sec’y of Health & Human Servs., 592 F.3d 1315, 1321–22 (Fed. Cir. 2010)); Oliver v. Sec’y of Health & Hum. Servs., 900 F.3d 1357, 1361 (Fed. Cir. 2018) (quoting Althen, 418 F.3d at 1278); see also Henkel v. Sec’y of Health & Hum. Servs., No. 23-1894, 2024 WL 3873569, at *1 (Fed. Cir. Aug. 20, 2024) (“Because we conclude that the special master’s finding on Althen prong three was not arbitrary or capricious . . . and because Appellants needed to prevail on all three prongs to have their petition granted, we affirm the petition’s denial without reaching the prong-two finding.”). “Once a petitioner establishes a prima facie case, the government then bears the burden of establishing alternative causation by a preponderance of the evidence.” Cedillo, 617 F.3d at 1335 (citing Walther v. Sec’y of Health & Hum. Servs., 485 F.3d 1146, 1151 (Fed. Cir. 2007)). After such a burden shift, the respondent must demonstrate by a preponderance of the evidence that the injury described in the petition was caused by factors unrelated to the administration of the vaccine described in the petition. 42 U.S.C. § 300aa–13(a)(1)(B); Althen, 418 F.3d at 1278 (citing Knudsen v. Sec’y of Health & Hum. Servs., 35 F.3d 543, 547 (Fed. Cir. 1994)). However, if Petitioner fails to establish a prima facie case, the burden does not shift to Respondent. See Doe v. Sec’y of Health & Hum. Servs., 601 F.3d 1349, 1358 (Fed. Cir. 2010). Regardless of whether the burden shifts, 35 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 36 of 58 the special master may consider evidence of alternative causation presented by the respondent in determining whether the petitioner has established a prima facie case, as the special master is to consider the record as a whole in determining causation where multiple possible sources of injury may exist. de Bazan, 539 F.3d at 1353; Stone v. Sec’y of Health & Hum. Servs., 676 F.3d 1373, 1379–80 (Fed. Cir. 2012). In her second Motion for Review, Petitioner raises two objections to the Chief Special Master’s Remand Decision. MFR at 5−6. First, that the Chief Special Master’s assessment of Petitioner’s medical literature evidence offered in support of Althen prong one constitutes legal error. Id. Second, that the Chief Special Master’s conclusions as to Althen prong two were contrary to law. Id. at 6. Having once again considered the record evidence and law applicable to this case, for the reasons explained below, this Court rejects both of Petitioner’s objections, and holds that the Chief Special Master’s conclusions do not constitute legal error. The Chief Special Master’s Decision is sustained. I. The Chief Special Master’s Appropriately Evaluated Petitioner’s Althen Prong One Theory. Petitioner broadly contends that the Chief Special Master’s evaluation of her prong one theory constitutes legal error. MFR at 5−6, 12–22. This claim encompasses several more specific arguments. First, Petitioner argues that the Chief Special Master’s “erroneous assessment of the medical literature evidence” constitutes legal error, as he (i) purportedly viewed the evidence through improper medical standards—rather than through the vantage point of the Vaccine Act’s preponderance standard—and (ii) improperly rejected circumstantial evidence. Id. at 12–20. Second, Petitioner asserts that the Chief Special Master’s credibility determinations were 36 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 37 of 58 improper. Id. at 20−22. Third, she contends that several of the Chief Special Master’s factual findings are arbitrary and capricious.27 Id. at 15. Respondent argues that “[t]he Chief Special Master’s conclusion that petitioner did not establish a reliable medical theory of vaccine causation under Althen prong one is well supported by the record,” and that he “articulated and applied the correct legal standards, thoroughly considered the relevant evidence, and explained in detail the rationale behind his Decision.” Resp. at 12−13. The Chief Special Master’s Decision makes clear that he appropriately applied the Althen prong one standard. Both the standard the Chief Special Master articulated and the manner in which he applied that standard reflect that he required Petitioner to prove a “reliable medical theory of causation specific to the vaccine and injury in question,” as required by Federal Circuit precedent. Cerrone, 146 F.4th at 1121 n.3; Decision at 32 (stating that Petitioner’s burden at prong 27 Petitioner’s first numbered objection asserts only legal error with respect to prong one, and did not include in any specific objections to the Chief Special Master’s factual findings. MFR at 5–6. Accordingly, Petitioner waived such factual challenges. SmithKline Beecham Corp. v. Apotex Corp., 439 F.3d 1312, 1319 (Fed. Cir. 2006) (“Our law is well established that arguments not raised in the opening brief are waived.”); Hodge ex rel. Elson v. Sec’y of Health & Hum. Servs., 168 Fed. Cl. 117, 129 n.13 (2023) (“Because petitioner did not explicitly raise such an argument, she has waived it.”); Miller v. Sec’y of Health & Hum. Servs., 172 Fed. Cl. 762, 779 (2024) (concluding that the petitioner waived her challenge to a specific finding of the special master, where she “failed to state it as an objection or adequately raise it in her Motion for Review or Memorandum of Objections”); see also Vaccine Rule 24 (requiring that a motion for review of a special master’s decision must “be accompanied by a memorandum of numbered objections to the decision” which “fully and specifically state[s] and support[s] each objection” to the special master’s decision). Nevertheless, in her Motion, Petitioner describes several of the Chief Special Master’s findings as “arbitrary.” MFR at 15 (“[T]he Chief arbitrarily concluded that Dr. Gish’s testimony did not ‘adequately substantiate’ the reliable mechanistic explanation.” (citing Decision at 44)); id. (“The Chief [Special Master’s] finding that ‘other proposed mechanisms’ were inadequate was arbitrary, as he recognized that bystander activation is ‘another way’ AIH might occur.”). Accordingly, for comprehensiveness, the Court addresses these two factual issues Petitioner references in her Motion, despite that they were not properly raised as objections. See Vaccine Rule 24. 37 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 38 of 58 one is to provide a theory based on “sound and reliable medical or scientific explanation” which is “legally probable, not medically or scientifically certain” (quoting Knudsen v. Sec’y of Health & Hum. Servs., 35 F.3d 543, 548−49 (Fed. Cir. 1994))); Decision at 16−30 (discussing the merits of each item of medical literature filed by Petitioner).28 As the Chief Special Master explained in his Decision, he simply required her to “knit[] together [] an overall theory that does not amount to speculation or unreasonable extrapolation.” Decision at 53; Cerrone, 146 F.4th at 1122 (“The special master correctly explained that ‘the evidence a claimant offers must, in totality, always accomplish one thing in the end: preponderantly establish that the vaccine(s) at issue more likely than not can cause the relevant disease.’” (emphasis in original)). This analysis is entirely consistent with the “heavy” burden the Vaccine Act imposes on petitioners raising off-Table claims. Hodges, 9 F.3d at 961 (“Bring the case within the timetable and specifications of a Table Injury and the statute does the heavy lifting—causation is conclusively presumed. Failing that, the heavy lifting must be done by the petitioner, and it is heavy indeed.”); Cerrone, 146 F.4th at 1121 n.3. Accordingly, for the reasons explained below, the Court holds that Chief Special Master’s well-reasoned analysis of Petitioner’s prong one theory did not constitute legal error. 28 The Court notes that Petitioner appears to understate in her brief what she must prove to satisfy Althen prong one. See MFR at 11 (“[O]ne reliable scientific methodology experts can use to establish a legally probable medical theory is to preponderantly prove that alleged vaccine causal relationship has biological credibility, i.e., is supported by a plausible biological theory.”); see also id. at 12 (describing prong one as “concluding a biological theory is plausible”). Petitioner’s prong one burden is “to show a reliable medical theory of causation specific to the vaccine and injury in question, not merely one that is plausible.” Cerrone, 146 F.4th at 1121 n.3. At Oral Argument, Plaintiff agreed that this is the correct standard. OA Tr. at 13:11−22. Indeed, the Federal Circuit has “repeatedly stated that ‘simply identifying a “plausible” theory of causation is insufficient for a petitioner to meet her burden of proof.’” Id. 38 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 39 of 58 A. The Chief Special Master’s Analysis of Petitioner’s Medical Literature Did Not Constitute Legal Error. Petitioner argues that the Chief Special Master’s “erroneous assessment of the medical literature evidence” constitutes legal error. MFR at 12−20. First, she contends that the Chief Special Master assessed the evidence through rigorous medical standards—or “the lens of the laboratorian”—rather than “the vantage point of the Vaccine Act’s preponderance standard.” Andreu v. Sec’y of Health & Hum. Servs., 569 F.3d 1367, 1380 (Fed. Cir. 2009); MFR at 12–13 (first citing id.; and then citing Doles v. Sec’y of Health & Hum. Servs., No. 2023-2404, 2025 WL 1177875, at *6−8 (Fed. Cir. Apr. 23, 2025)). Second, Petitioner contends that the Chief Special Master improperly rejected circumstantial evidence supporting her prong one theory. MFR at 13– 20. For the reasons stated below, the Court concludes that neither of these arguments provide a sufficient basis for setting aside the Decision. 1. The Chief Special Master Did Not Evaluate the Evidence “Through the Lens of the Laboratorian.” Petitioner argues that the Chief Special Master improperly assessed the evidence through rigorous medical standards—or “the lens of the laboratorian”—rather than “the vantage point of the [Vaccine] Act.” Andreu, 569 F.3d at 1380; MFR at 12–13 (first citing id.; and then citing Doles, 2025 WL 1177875, at *6−8). The Court disagrees with Petitioner’s contention. As a general matter, Petitioner is correct that “[m]edical literature and epidemiological evidence must be viewed . . . not through the lens of the laboratorian, but instead from the vantage point of the Vaccine Act’s preponderant evidence standard.” Andreu, 569 F.3d at 1380 (quoting Bunting v. Sec’y of Health & Human Servs., 931 F.2d 867, 873 (Fed. Cir. 1991)). But this standard is best understood simply as contrasting the just over 50% likelihood required to make a preponderant showing with the “95% probability” required for attribution of causation in the medical field. Andreu, 569 F.3d at 1380; Doles, 2025 WL 1177875, at *3 (“So, a proffered medical 39 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 40 of 58 theory of causation is measured by preponderance of evidence, not by whether the theory satisfies the standards of medical research.”); Bunting, 931 F.2d at 873 (“The standard of proof required by the Act is simple preponderance of evidence; not scientific certainty.”). Although a “claimant need not produce medical literature or epidemiological evidence to establish causation under the Vaccine Act, where such evidence is submitted, the special master can consider it in reaching an informed judgment . . . .” Andreu, 569 F.3d at 1379. This is precisely the role of the special master: to “judg[e] the merits of individual claims.” Hodges, 9 F.3d at 961 (“Congress assigned to a group of specialists, the Special Masters within the Court of Federal Claims, the unenviable job of sorting through these painful cases and, based upon their accumulated expertise in the field, judging the merits of the individual claims.”); Cerrone, 146 F.4th at 1122 (“The special master correctly explained that ‘the evidence a claimant offers must, in totality, always accomplish one thing in the end: preponderantly establish that the vaccine(s) at issue more likely than not can cause the relevant disease.’” (emphasis in original)). Indeed, “finders of fact are entitled—indeed, expected—to make determinations as to the reliability of the evidence presented to them and, if appropriate, as to the credibility of the persons presenting that evidence.” Moberly, 592 F.3d at 1326. Here, the Chief Special Master’s thorough analysis was entirely consistent with this command. The Chief Special Master expressly recognized that “scientific evidence offered to establish Althen prong one is viewed ‘not through the lens of the laboratorian, but instead from the vantage point of the Vaccine Act’s preponderant evidence standard.’” Decision at 32 (quoting Andreu, 569 F.3d at 1380). Further, he dedicated almost two full pages of his analysis to explaining how the preponderance standard is applied in cases arising under the Vaccine Act. Id. at 52–54. In doing so, he made clear that his “evaluation of this claim [] does not amount to a 40 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 41 of 58 heightening of the preponderant burden, requiring certainty even though the evidentiary test does not.” Id. at 53. The Chief Special Master did not simply recite the proper standard; his application of this preponderance standard to the facts before him reflects that he considered the evidence through the proper “vantage point.” Andreu, 569 F.3d at 1380; see, e.g., Decision at 39 (acknowledging that “[s]ome elements of [Petitioner’s] theory are wholly noncontroversial” but that “the theory, in its totality lacks sufficient preponderant support, even if some individually-reliable items of literature have been offered in this case”); id. at 42–43 (explaining that there were “too many missing links in the causation chain” to conclude that the Tdap vaccine likely leads to an AIH disease process, and explaining why the literature Petitioner provided in support of this claim did not ultimately “bridge th[e] evidentiary gap sufficiently”). Petitioner’s citation to Doles does not support her argument. MFR at 7–9, 12–14. In Doles, the Federal Circuit held—on a narrow, fact-bound basis—that it was error to fault the relevance of a study “solely for the study’s lack of statistically significant conclusions regarding patients identically situated to [the petitioner].” Doles, 2025 WL 1177875, at *8. There, the study in question involved the same injury and vaccines as those at issue in the case, and the Federal Circuit recognized that the study “contain[ed] circumstantial evidence which demonstrate[d] that [the petitioner’s] vaccines” were capable of impacting her brain in the manner posited by her proposed medical theory. Id. at *4−5. By contrast, here, the Chief Special Master did not exclude from his analysis or otherwise “fault” certain evidence simply because the data was not statistically significant. See Decision at 16–30 (discussing every item of medical literature Petitioner filed); Doles, 2025 WL 1177875, at *8. Rather, the Chief Special Master considered the totality of the evidence, and thoroughly 41 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 42 of 58 explained why, based on his judgment, the preponderance standard had not been met. Id. at 39 (“[Petitioner’s] theory in its totality lacks sufficient preponderant support, even if some individually-reliable items of literature have been offered in this case.” (emphasis in original)). This is precisely the sort of judgment which is squarely “within the purview of the fact finder.” Porter, 663 F.3d at 1249 (“We do not reweigh the factual evidence, assess whether the special master correctly evaluated the evidence, or examine the probative value of the evidence or the credibility of the witnesses . . . .”); see R.J. ex rel. W.J. v. Sec’y of Health & Hum. Servs., 93 F.4th 1228, 1235 (Fed. Cir. 2024) (“It is within a special master’s discretion to weigh evidence.”); Rogero v. Sec’y of Health & Hum. Servs., 748 F. App’x 996, 1001 (Fed. Cir. 2018) (“Determinations of relative weight of different evidence are generally for the trier of fact.”). Further, where the Chief Special Master declined to afford significant weight to certain items of evidence, he articulated a rational explanation for doing so. Kirby, 997 F.3d at 1381 (“[R]eversible error is extremely difficult to demonstrate if the special master has considered the relevant evidence of record, drawn plausible inferences and articulated a rational basis for the decision.” (alteration in original) (quoting Lampe, 219 F.3d at 1360)); see, e.g., Decision at 40 (explaining the limitations of the Munyer, Nanan, Christen, Robertson, and Mieli-Vergani I articles as support for Petitioner’s theory regarding the measles component of the MMR vaccine); see also infra Discussion § I.A.2. (discussing the Chief Special Master’s analysis of Petitioner’s case reports, and his reasons for declining to give those studies weight). Petitioner also contends that because Respondent’s experts reviewed the evidence through a medical lens, and the Chief Special Master relied heavily on their testimony, that the Chief Special Master, too, applied “rigorous” medical standards in assessing her prong one theory. MFR at 20. But the standard the experts applied has little to do with the standard the Chief Special 42 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 43 of 58 Master applied. This is especially true where, as here, the Chief Special Master so clearly explained how each item of evidence either supported or failed to support petitioner’s theory. See e.g., Decision at 42 (noting that da Silva Antunes “includes no discussion of AIH”); id. at 40 (“Christen, for example, only briefly mentions the measles vaccine, but notes that evidence connecting it to AIH was not corroborated over time.”); id. at 46 (“Rennick has more to say about the function of the measles vaccine from an immunologic standpoint than it does about the vaccine’s allegedly-pathogenic capacity (which is what is at issue in this case).”); Kirby, 997 F.3d at 1381 (quoting Lampe, 219 F.3d at 1360) (“[R]eversible error is extremely difficult to demonstrate if the special master has considered the relevant evidence of record, drawn plausible inferences and articulated a rational basis for the decision.”). 2. The Chief Special Master Did Not Improperly Reject Circumstantial Evidence. Next, Petitioner argues that the Chief Special Master improperly declined to give weight to certain circumstantial evidence that she believes is relevant. MFR at 12−20 (“In his improper medical literature assessment, the Chief [Special Master], on the other hand, narrowly rejected every type of medical literature and scientific explanation provided, and then relying heavily on Respondent’s opposing vantage point, assessed the evidence through the rigorous medical standards and narrowly concluded that the evidence was not scientifically or medically sufficient to meet the legally probable burden.”). Respondent counters that “the Chief Special Master made clear that the problem with petitioner’s evidence was not that it was circumstantial, but that it was insufficient to meet her burden.” Resp. at 15–16. In Respondent’s view, the Chief Special Master “clearly did not demand ‘complete and direct proof.’ He did, however, demand preponderant proof, which is required by statute and precedent, and which he rightly found to be lacking.” Id. at 17 (citation omitted) (citing Althen, 418 F.3d at 1280)). 43 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 44 of 58 The Court agrees with Respondent. As an initial matter, Petitioner did not cite any evidence that the Chief Special Master failed to consider in his Decision. See generally MFR. Nor could she, as he addressed every piece of medical literature she had presented. Decision at 16–30, 39–48. But more to the point, as noted above, the Chief Special Master simply undertook the analysis which was required of him: determining whether Petitioner’s evidence, “in totality . . . preponderantly establish[es] that the vaccine(s) at issue more likely than not can cause the relevant disease.” Cerrone, 146 F.4th at 1122; see, e.g., Decision at 41 n.24 (explaining that “the evidence of a more direct vaccine-AIH association is not evident (underscoring the degree to which Petitioner must rely on more indirect and circumstantial proof—and here, that proof too proves inadequate)”); Olson v. Sec’y of Health & Hum. Servs., 135 Fed. Cl. 670, 679 (2017), aff’d, 758 F. App’x 919 (Fed. Cir. 2018) (“[A]s Petitioner offered evidence of a specific biologic mechanism, the Special Master was then required to consider it and evaluate its persuasiveness.”); Porter, 663 F.3d at 1249; R.J., 93 F.4th at 1235; Rogero, 748 F. App’x at 1001. Here, the Chief Special Master provided detailed reasons for declining to afford significant weight to both certain items of medical literature and aspects of Petitioner’s theory; his analysis and the rationales provided were rational, well-supported by the record, and thoroughly explained in the Decision. For instance, the Chief Special Master dedicated several pages of his analysis to the “primary thrust” of Petitioner’s causation argument—that the measles component of the MMR vaccine caused immunosuppression which, in turn, “open[ed] the door” for her AIH. See Decision at 39–42; see also id. at 16, 21–24 (summarizing and analyzing each of the articles supporting this component of Petitioner’s theory). In his analysis, the Chief Special Master explained that two of the articles Petitioner relied upon, Nanan and Munyer, were (i) dated and (ii) did not stand for the proposition that “that the studied patients experienced meaningful immune suppression, such that 44 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 45 of 58 any disease became more likely after receipt of the vaccine (let alone AIH).” Id. at 40 (emphasis in original). This analysis was reasonable, given the Chief Special Master’s findings that Nanan did not offer evidence that the patients considered in the study “experienced any actual immune suppression sufficient to cause disease,” and Munyer observed that “experimental stimulation of blood samples revealed an impairment in immune cells,” but that “actual, in vivo vaccination did not.” Id. at 23 (citing Hr’g Tr. at 163); id. at 24 (describing Munyer as “a single (and facially- outdated) ‘brick’ in the causation theory ‘wall’ Petitioner seeks to build,” and noting that Munyer did not “itself establish vaccine-related pathology”). In her Motion, Petitioner specifically focuses on a bystander activation theory.29 MFR at 13–20. Specifically, Petitioner faults the Chief Special Master for concluding that Dr. Gish’s bystander activation theory was not “yoked to sufficient reliable proof.” Id. at 13 (citing Decision at 47). However, the Chief Special Master’s approach to this aspect of Petitioner’s theory was reasonable. Decision at 46–47. The Chief Special Master explained that one of the articles on which Petitioner relied for this point, Benn, “focused on the positive, secondary effects of [] nonspecific immune stimulation, rather than supporting the contention that vaccine-associated bystander activation is harmful.” Id. (emphasis added) (citing Benn at 432, 436–37); see also id. 29 Petitioner contends that “Respondent’s experts agree” that “bystander activation is a reputable biological mechanism” which is “the unexpected activation of immune cells.” MFR at 13 (citing H’rg Tr. at 158−59). However, in the portion of the transcript Petitioner cites, Dr. MacGinnitie expressly stated that “no literature that was provided suggest[ed] that vaccination can cause bystander activation,” and further that Petitioner’s medical records did not show that she “had excessive inflammation immediately after vaccination.” H’rg Tr. at 159:14–160:23. This testimony supported the Chief Special Master’s conclusion that “Dr. MacGinnitie persuasively explained that usually bystander activation would only be thought to occur in the presence of active inflammation due to an infectious process,” and—importantly—this “was never shown to have happened in this case.” Decision at 46–47 (citing H’rg Tr. at 158–60); Moberly, 592 F.3d at 1324 (holding special master did not err in rejecting a theory of causation where “there was no evidence in the record suggesting that the proposed mechanism was at work in [the petitioner’s] case”). 45 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 46 of 58 at 17 (“Benn, however, primarily focuses on the positive rather than pathologic indirect effects of vaccination.”(emphasis in original)). And more broadly, the Chief Special Master explained that although Dr. Gish’s assertions were “consistent with how AIH likely unfolds,” Dr. Gish had not provided enough proof that the vaccine “can be an aspect of the disease process.” Id. at 47. Petitioner also argues that the Chief Special Master “incorrectly discounted the probative relevance” of the case reports she presented. MFR at 17−20. This argument, too, is unavailing. The Chief Special Master “articulated a rational basis” for declining to give weight to the case report evidence cited by Petitioner. Kirby, 997 F.3d at 1381 (quoting Lampe, 219 F.3d at 1360).30 The Chief Special Master explained that many of Petitioner’s case reports “do not involve the Tdap or MMR vaccines (or even comparable wild virus infections),” which “greatly saps such case reports of evidentiary value in the context of this case.” Decision at 45. Therefore, in the Chief Special Master’s view, “the paucity of case reports specific to the vaccines at issue and AIH do not appreciably add to the total picture.” Id. at 46. In other words, he did not wholly discount the value of this evidence; he simply explained why, in this particular case, the case reports that were filed—many of which did not involve the relevant vaccine or disease at issue—did not lend much credence to Petitioner’s causation theory. This conclusion was plainly rational, given that Petitioner’s task is to demonstrate a theory that is “specific to the vaccine and injury in question.” Cerrone, 146 F.4th at 1121 n.3; OA Tr. at 13:11−22; see Herms v. Sec’y of Health & Hum. Servs., 30 Although there is some disagreement regarding the evidentiary value of case reports, there does appear to be some consensus that they can provide evidence of association or correlation, but do not prove “causation definitively”—and accordingly there are limits to their evidentiary value. Echols v. Sec’y of Health & Hum. Servs., 165 Fed. Cl. 9, 18 (2023) (“[C]ase reports ‘do not purport to establish causation definitively, and this deficiency does indeed reduce their evidentiary value’ . . . [but] ‘the fact that case reports can by their nature only present indicia of causation does not deprive them of all evidentiary weight.” (quoting Paluck v. Sec’y of Health & Hum. Servs., 104 Fed. Cl. 457, 475 (2012)); Broussard v. Sec’y of Health & Hum. Servs., No. 18-302V, 2024 WL 1829210, at *8–14 (Fed. Cl. Apr. 4, 2024). 46 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 47 of 58 No. 19-70V, 2024 WL 1340669, at *21 (Fed. Cl. Spec. Mstr. Mar. 4, 2024) (“Petitioner does not explain how data from other unrelated vaccines could be extrapolated to the vaccines at issue here and accordingly, the data is not persuasive.”), review denied, 173 Fed. Cl. 1 (2024). Petitioner again analogizes to Doles, asserting that “[l]ike the individual data relied upon in Doles, Dr. Gish relied on relevant, even if not medically certain case reports supporting a theory that the identical vaccine components, especially when administered in combination, are associated with onset AIH or acute hepatitis symptoms.” MFR at 19−20 (citing Doles, 2025 WL 1177875, at *8). As explained above, this case was different from Doles, in that the study in question in Doles did include the vaccine and injury at issue, and the judge had faulted a study’s relevance simply due to a lack of “statistically significant conclusions regarding patients identically situated to” the petitioner. Doles, 2025 WL 1177875, at *8 (emphasis in original). By contrast, here, the Chief Special Master observed that (i) case reports in general are not strong evidence of causation and (ii) here, as many of Petitioner’s case reports involved different vaccines and injuries than those at issue, they merit even less probative weight. Decision at 45–46. The Chief Special Master did not wholly discount the value of this form of evidence—he reasonably acknowledged that case reports “may be the place to start a causation inquiry, but that effort must then build upon other evidence that suggests the temporal/coincidental observation of post- vaccination injury is scientifically meaningful.” Id. at 46. In sum, the Chief Special Master’s analysis reflects that he carefully considered the medical literature Petitioner presented, and found certain articles to provide only weak evidence of causation because they were not sufficiently tethered to the concept of vaccine causation of the disease at issue. Cerrone, 146 F.4th at 1120–1122 & n.3; Herms, 2024 WL 1340669, at *21; Porter, 663 F.3d at 1249; R.J., 93 F.4th at 1235; Rogero, 748 F. App’x at 1001. Accordingly, 47 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 48 of 58 Petitioner’s argument that the Chief Special Master improperly rejected circumstantial evidence fails. B. The Chief Special Master Did Not “Cloak the Application of an Erroneous Legal Standard in the Guise of a Credibility Determination.” Petitioner’s next argument is an extension of her prior arguments. She argues that the Chief Special Master purportedly imposed a heightened burden at prong one by “disguising an impermissible legal burden” as a credibility determination, specifically by crediting Respondent’s expert’s theories over Dr. Gish’s. MFR at 20−22. According to Petitioner, this determination is “squarely within this Court’s review,” because this aspect of the Chief Special Master’s analysis amounted to “an improper evidentiary burden.” Id. at 21. The Court rejects Petitioner’s argument. Special masters are “entitled—indeed, expected—to make determinations as to the reliability of the evidence presented to them and if, appropriate, as to the credibility of the persons presenting that evidence.” Moberly, 592 F.3d at 1325–26; see also Cerrone, 146 F.4th at 1124– 25 (“[C]redibility determinations are virtually unreviewable on appeal.”); Munn, 970 F.2d at 871 (“[O]f course we do not examine the probative value of the evidence or the credibility of the witnesses. These are all matters within the purview of the fact finder.”). “The special master’s decision often times is based on the credibility of the experts and the relative persuasiveness of their competing theories.” Broekelschen v. Sec’y of Health & Hum. Servs., 618 F.3d 1339, 1347 (Fed. Cir. 2010) (citing Lampe, 219 F.3d at 1362). Petitioner is correct that special masters cannot “cloak the application of an erroneous legal standard in the guise of a credibility determination, and thereby shield it from appellate review.” Andreu, 569 F.3d at 1379. But this simply means that the fact finder cannot “reject evidence based on an unduly stringent legal test while characterizing the rejection as based on the reliability of particular evidence or the credibility of a particular witness.” Moberly, 592 F.3d at 1326. That is not what occurred here. 48 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 49 of 58 Here, the Chief Special Master dedicated an entire section of his prong one analysis to explaining why he was more persuaded by Respondent’s experts than Petitioner’s. Decision at 47. First, the Chief Special Master recognized that Dr. Gish was “certainly qualified to offer an opinion in this case . . . given his expertise in hepatology.” Id. However, the Chief Special Master explained that Dr. Gish lacked expertise in both “AIH’s pathogenesis” and immunology, and that his contentions were “generalized and somewhat broad.” Id. Further, Respondent’s expert, Dr. Crippin—also a hepatologist—offered competing testimony, and Dr. Gish’s opinions “were persuasively rebutted by Dr. MacGinnitie—the sole immunologist who testified” in the case. Id. The Chief Special Master also noted that it was difficult to follow Dr. Gish’s theory, which the Chief Special Master described as “excessively wordy, meandering, and unclear in the theory it embraced,” which “detract[ed] from the theory’s persuasiveness.” Id. n.26. For all of these reasons, the Chief Special Master gave Dr. Gish’s contentions less weight than Respondent’s expert. Id. at 47–48 (“Dr. Gish’s theory did not add up, independent of his expertise as a hepatologist, and even if some of its components were individually reliable.”). The Court concludes that the Chief Special Master “articulated a rational basis” in support of his determination to afford less weight to Dr. Gish’s testimony than that of Dr. Crippin and Dr. MacGinnitie. Kirby, 997 F.3d at 1381 (quoting Lampe, 219 F.3d at 1360). It was reasonable for the Chief Special Master to consider the experts’ respective areas of expertise and to consider the clarity—or lack thereof—of the theories presented. Olson v. Sec’y of Health & Hum. Servs., 758 F. App’x 919, 925 (Fed. Cir. 2018) (“The Special Master did not require evidence from an immunologist, but rather properly evaluated [the expert’s] individual competence to opine on the matters at issue.”). Petitioner’s belief that there is “more than adequate objective evidence supporting Dr. Gish’s opinion” is not a sufficient basis for finding that the Chief Special Master’s 49 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 50 of 58 analysis of the expert testimony in this case was legal error. MFR at 21. Accordingly, the Court discerns no legal error in the Chief Special Master’s weighing of the expert testimony in this case. Cerrone, 146 F.4th at 1124–25 (finding no error where the Chief Special Master concluded that petitioner’s expert opinions were less credible and persuasive than those of respondent’s expert); Tullio v. Sec’y of Health & Hum. Servs., 149 Fed. Cl. 448, 475 (2020) (“Although the Special Master in his decision appears to give more credence to the respondent’s experts than to petitioner’s experts, he did carefully review all the evidence before him in reaching his ultimate conclusion denying compensation and was not arbitrary or capricious in doing so.”). C. The Chief Special Master’s Factual Findings Were Not Arbitrary or Capricious. In addition to the legal challenges discussed above, Petitioner also appears to challenge two of the Chief Special Master’s factual conclusions. MFR at 15. First, she argues that the Chief Special Master’s conclusion that Dr. Gish did not adequately substantiate molecular mimicry as a causal mechanism for AIH was arbitrary. Id. However, the Chief Special Master reasonably concluded that there is “very little evidence in this record that would support molecular mimicry due to vaccination as a mechanistic explanation for AIH,” given that Dr. Gish did not (i) demonstrate a homology,31 and (ii) “did not otherwise offer evidence suggesting that the vaccines or their wild viral counterparts are associated with any antibodies thought to drive AIH or be involved in its pathogenesis.” Id. at 44. This conclusion was reasonable, particularly in view of Dr. MacGinnitie’s testimony that he was not aware of any evidence in medical literature of molecular mimicry occurring between the components of the MMR and Tdap vaccines and liver antigens. See Hr’g Tr. at 156:4–18; W.C. v. Sec’y of Health & Hum. Servs., 704 F.3d 1352, 1360– 31 In the context of molecular mimicry, a “homology” is a similar sequence found in both a pathogenic or disease-causing protein and a human or “self” protein which would cause the immune system to “cross-react” (or attack) both. See H’rg Tr. at 156:19–157:24. 50 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 51 of 58 61 (Fed. Cir. 2013) (affirming rejection of petitioner’s molecular mimicry theory where “[t]he special master reasonably considered the lack of evidence connecting the cross-reactivity observed by [the petitioner’s study] to the facts of [the p]etitioner’s case to weigh” against an expert’s molecular mimicry theory); Pierson v. Sec’y of Health & Hum. Servs., No. 17-1136V, 2022 WL 322836, at *25 (Fed. Cl. Jan. 19, 2022) (“[A] petitioner must offer more than superficial invocation of molecular mimicry as the causal mechanism.”). Second, Petitioner argues that “[t]he Chief [Special Master’s] finding that ‘other proposed mechanisms’ were inadequate was arbitrary, as he recognized that bystander activation is ‘another way’ AIH might occur.” MFR at 15 (quoting Decision at 46). However, as Respondent notes, in the portion of the Decision Petitioner cites, the Chief Special Master simply recounted Petitioner’s argument with respect to bystander activation, and did not accept the theory himself. Decision at 46 (“Petitioner proposed bystander activation of nonspecific immune cells (and/or suppression leading to expansion of these immune cells) as another way AIH might occur.”). As explained above, the Court finds that Chief Special Master’s conclusions with respect to Petitioner’s bystander activation theory were reasonable. See supra Discussion § I.A.2. * * * * * In sum, the Court concludes that the Chief Special Master properly evaluated Petitioner’s prong one theory, and held her to her burden to “show a reliable medical theory of causation specific to the vaccine and injury in question, not merely one that is plausible.” Cerrone, 146 F.4th at 1121 n.3. As another judge of this court has explained: “[This Court’s] role in evaluating a special master’s decision is not to quibble with the weight afforded certain pieces of evidence or substitute our determinations of credibility. Rather, we are empowered under the Vaccine Act only to act as a check on unreasonable decision-making.” Cerrone v. Sec’y of Health & Hum. Servs., 168 Fed. Cl. 745, 755 (2023), aff’d, 146 F.4th 1113. 51 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 52 of 58 Here, the Chief Special Master’s decision-making in this case was reasonable and well- supported by the record. The Chief Special Master did not, as Petitioner contends, impose a heightened burden upon her prong one theory by any means—not by evaluating her evidence “through the lens of the laboratorian,” not by improperly rejecting circumstantial evidence, and not by disguising a heightened burden as a credibility determination. Andreu, 569 F.3d at 1379– 80. Rather, the Chief Special Master reasonably concluded that her theory “in its totality lacks sufficient preponderant support, even if some individually-reliable items of literature have been offered in this case.” Decision at 39 (emphasis in original). Put another way, although Petitioner had offered several threads of evidence, those threads did not “knit[] together into an overall theory that does not amount to speculation or unreasonable extrapolation.” Id. at 53−54 (“To meet the preponderant standard, sufficient evidence must be presented to allow for the conclusion that the vaccine ‘more likely than not’ acted as proposed. That was not accomplished in this case, even though Petitioner has offered some reliable evidence plus an experienced hepatologist to convey her causation opinion.”). Accordingly, the Court rejects Petitioner’s argument that the Chief Special Master’s evaluation of her prong one theory constitutes legal error. II. The Chief Special Master’s Conclusions as to Prong Two Were Not Arbitrary, Capricious, or Otherwise Contrary to Law. Petitioner next argues that the Chief Special Master’s analysis of prong two warrants reversal for two reasons. First, she contends that his conclusion that “[t]he medical record simply does not contain sufficient facts suggesting the vaccines had anything to do with Petitioner’s disease,” was arbitrary and capricious. MFR at 22 (citing Decision at 51). Second, she contends that the Chief Special Master erred by “ignor[ing] case report evidence that is circumstantially on 52 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 53 of 58 point with Mrs. Exum’s facts,” along with other medical literature, which, she contends, “circumstantially support” a finding of vaccine causation in Petitioner’s case.32 Id. at 22–23. Evidence offered in support of one prong can support the other Althen prongs. Capizzano v. Sec’y of Health & Hum. Servs., 440 F.3d 1317, 1326 (Fed. Cir. 2006) (“We see no reason why evidence used to satisfy one of the Althen [] prongs cannot overlap to satisfy another prong.”). However, this does not in any way lessen Petitioner’s burden to prove that the vaccine caused her injury in her particular case. The second prong of Althen “requires the petitioner to prove, by a preponderance of the evidence, that the medical theory was in fact the mechanism that resulted in the injury at issue.” Cerrone, 146 F.4th at 1121 (emphasis added) (citing Broekelschen, 618 F.3d at 1345 (“Because causation is relative to the injury, a petitioner must provide a reputable medical or scientific explanation that pertains specifically to the petitioner’s case . . . .”)); Capizzano, 440 F.3d at 1327 (“The second prong of the Althen [] test is not without meaning.”); Nussman v. Sec’y 32 Petitioner also makes a passing suggestion that the burden had shifted to Respondent to prove that a “factor[] unrelated” to the vaccine was more likely than not the cause of Petitioner’s AIH, and that Respondent failed to make that showing. See 42 U.S.C § 300aa-13(a); Doe v. Sec’y of Health & Hum. Servs., 601 F.3d 1349, 1357 (Fed. Cir. 2010) (“While the burden of proving a prima facie case is on the petitioner, the government has the burden of showing the injury or death was caused by a ‘factor unrelated.’”). However, only “[o]nce a petitioner establishes a prima facie case, the government then bears the burden of establishing alternative causation by a preponderance of the evidence.” Cedillo, 617 F.3d at 1335 (emphasis added) (citing Walther v. Sec’y of Health & Hum. Servs., 485 F.3d 1146, 1151 (Fed. Cir. 2007)). The Chief Special Master made this precise point in his analysis and then stated that he “ha[d] not found the burden should be, or was, shifted here.” Decision at 50. To the extent that Petitioner argues that the Chief Special Master erred in denying her compensation because the Government could not prove that a factor unrelated was the cause of her AIH, her argument is necessarily unavailing. Winkler v. Sec’y of Health & Hum. Servs., 88 F.4th 958, 963 (Fed. Cir. 2023) (“[T]he failure to prove an alternate cause does not obviate the need for proof of causation by the vaccine.”). Said differently, regardless of whether the Government can preponderantly prove that a factor unrelated to the vaccine caused the disease, the onus is always on the Petitioner to first prove her prima facie case. The Chief Special Master, in his thorough and well-reasoned opinion, concluded that Petitioner had not done so. Decision at 51 (“The medical record simply does not contain sufficient facts suggesting the vaccines had anything to do with Petitioner’s disease. The second Althen prong has not been preponderantly established.”). 53 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 54 of 58 of Health & Hum. Servs., 83 Fed. Cl. 111, 121 (2008) (“Proof of a medical theory explaining how a vaccine could cause an injury is analytically distinct from proof that a vaccine actually did cause the injury.”). In other words, the Vaccine Act requires that Petitioner preponderantly prove a “logical sequence of cause and effect”—that the vaccine more likely than not “did cause” her illness here. Boatmon, 941 F.3d at 1359, 1362 (quoting Althen, 418 F.3d at 1278). A. The Chief Special Master’s Conclusion that Petitioner Did Not Prove a “Logical Sequence of Cause and Effect” Was Not Arbitrary and Capricious. Petitioner broadly contends that the Chief Special Master’s conclusion that “[t]he medical record simply does not contain sufficient facts suggesting the vaccines had anything to do with Petitioner’s disease,” was arbitrary and capricious. MFR at 22 (citing Decision at 51). The Decision, however, reflects that the Chief Special Master considered, appropriately weighed, and “dr[ew] plausible inferences and articulated a rational basis” for his conclusion with respect to prong two. Kirby, 997 F.3d at 1381 (quoting Lampe, 219 F.3d at 1360). The Chief Special Master gave several reasons for his conclusion that Petitioner had not preponderantly proven a “logical sequence of cause and effect showing that the vaccination was the reason for the injury,” as required to meet prong two. Althen, 418 F.3d at 1278; Decision at 48–51. First, he noted the “absence of objective record proof” in Petitioner’s medical records that would support the inference that Petitioner had an aberrant reaction to the vaccines. Decision at 48. This was the primary basis for his conclusion. Id. Second, the Chief Special Master noted that he had not identified any instance in which one of Petitioner’s treating physicians associated her AIH with the vaccines. Id. Third, the Chief Special Master explained that although the non- specific symptoms which manifested when she returned from her travel, such as fatigue, were likely related to her AIH, those symptoms were insufficient to carry her burden of proof. Id. at 48–49. Fourth, he noted the presence of risk factors for AIH—other than the vaccines—which 54 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 55 of 58 were present in Petitioner’s medical history. Id. at 49–50. These included her use of anti-malarial medication, supplements, and foreign travel. Id. at 49. This analysis was legally proper. Reversible error is “extremely difficult to demonstrate” where the special master has “considered the relevant evidence of record, drawn plausible inferences and articulated a rational basis for the decision.” Hines, 940 F.2d at 1528; Kirby, 997 F.3d at 1381 (quoting Lampe, 219 F.3d at 1360). Here, the Chief Special Master clearly did so. His analysis—which spans roughly three full pages—makes clear that he considered the relevant evidence, and it was entirely plausible for him to infer a lack of a causal connection between the vaccine and Petitioner’s AIH given the absence of evidence of such a connection in her medical records. See, e.g., Pet. Ex. 3 at 282 (PA noting “unclear etiology” of Petitioner’s condition on November 28, 2018); id. at 222 (hematologist diagnosing Petitioner with hepatitis on January 4, 2019 and noting that the “etiology [of her liver disease] is as yet unknown”); Cucuras v. Sec’y of Health & Hum. Servs., 993 F.2d 1525, 1528 (Fed. Cir. 1993) (“Medical records, in general, warrant consideration as trustworthy evidence.”); Capizzano, 440 F.3d at 1326 (“[M]edical records and medical opinion testimony are favored in vaccine cases, as treating physicians are likely to be in the best position to determine whether ‘a logical sequence of cause and effect show[s] that the vaccination was the reason for the injury.’” (quoting Althen, 418 F.3d at 1280)). The Chief Special Master even went so far as to explain the specific types of evidence that would indicate an aberrant response to the vaccines, such as inflammation or an infection. Decision at 48. Petitioner focuses on the nonspecific symptoms that Petitioner had experienced, like fatigue and nausea, but the Chief Special Master reasonably explained that those symptoms “are not enough of a basis to conclude that the two vaccines Petitioner received ‘did cause’ her AIH.” MFR at 22 (citing Decision at 52); Decision at 48. As the Chief Special Master noted, those 55 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 56 of 58 symptoms “did not immediately merit treatment” and “arguably were consistent with her pre- vaccination health.” Id. (“I also have not ascertained any instance where any of Petitioner’s treaters proposed the vaccinations explained her AIH (including Drs. Oloruntoba or Wu)).” Petitioner otherwise does not appear to argue that these specific reasons the Chief Special Master gave for his decision were irrational, nor does she point to evidence in Petitioner’s medical records that the Chief Special Master ignored. See generally MFR at 22–24. Indeed, when asked by the Court to “put aside all the medical literature for a moment and just focus[] on Ms. Exum’s medical records” and explain “what, for purposes of [p]rong two, is evidence that is specific to Petitioner” that would support her case, Petitioner’s counsel responded by continuing to discuss the case report evidence. OA Tr. at 37:22−38:5. At bottom, Petitioner simply takes issue with his ultimate conclusion—broadly asserting that “the totality of the medical literature evidence in combination with her medical facts, the logical progression of her medical sequence, the individual case report data, the biologically credible bystander activation theory, and the lack of any alternate causal factors . . . more than” satisfies the preponderance standard. Id. at 24. This Court, however, does not “reweigh the factual evidence, assess whether the special master correctly evaluated the evidence, or examine the probative value of the evidence or the credibility of the witnesses—these are all matters within the purview of the fact finder.” Porter, 663 F.3d at 1249. In sum, the Chief Special Master plainly “has considered the relevant evidence of record, drawn plausible inferences and articulated a rational basis” for his conclusion as to prong two. Kirby, 997 F.3d at 1381 (quoting Lampe, 219 F.3d at 1360). B. Chief Special Master’s Analysis of Petitioner’s Medical Literature Did Not Constitute Legal Error with Respect to Prong Two. Petitioner next contends that the Chief Special Master erred by “ignor[ing] objective case report evidence that is circumstantially on point with Mrs. Exum’s facts,” along with other medical 56 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 57 of 58 literature, which, she contends, circumstantially support a finding of vaccine causation in Petitioner’s case. MFR at 22–23. This argument is unavailing. Petitioner fails to point to specific studies that the Chief Special Master ignored, and also fails to explain precisely how these studies would lend support to the claim that Petitioner’s vaccines caused her AIH in her particular case. Id. The Chief Special Master discussed every item of medical literature Petitioner filed in this case—summarizing and discussing the merits of each.33 Decision at 16–30. Given the nature of the “did cause” inquiry at prong two, which is specific to each petitioner, it was not improper for the Chief Special Master to focus on the medical records and other evidence relating to Petitioner’s specific case. Cerrone, 146 F.4th at 1121 (citing Broekelschen, 618 F.3d at 1345; Capizzano, 440 F.3d at 1327; Nussman, 83 Fed. Cl. at 121. Petitioner argues that the medical literature on which Dr. Gish relied shows that “a vaccine causal theory is the most probable medical cause in [Petitioner’s] AIH case.” MFR at 23. However, this conclusory argument that a certain category of evidence, in general, supports Petitioner’s prong two argument is insufficient to demonstrate any legal error. This is particularly true where, as here, Petitioner fails to point to specific evidence that the Chief Special Master failed to consider. CONCLUSION For the reasons stated above, the Court finds that the Chief Special Master’s thorough examination of the record in Mrs. Exum’s case resulted in a decision that was not contrary to law. 33 Even if he had not done so, under Federal Circuit precedent, reviewing courts “generally presume that a special master considered the relevant record evidence even though he does not explicitly reference such evidence in his decision.” Moriarty v. Sec’y of Health & Hum. Servs., 844 F.3d 1322, 1328 (Fed. Cir. 2016). 57 Case 1:21-vv-01513-EMR Document 95 Filed 09/30/25 Page 58 of 58 The Chief Special Master’s Decision denying her petition is therefore SUSTAINED, and Petitioner’s Motion for Review (ECF No. 87) is DENIED. The Clerk of the Court is DIRECTED to enter Judgment consistent with this Memorandum and Order. The parties are directed to CONFER and FILE a Notice by September 29, 2025, attaching a proposed public version of this sealed Memorandum and Order, identifying any information subject to redaction pursuant to Vaccine Rule 18(b). IT IS SO ORDERED. Eleni M. Roumel ELENI M. ROUMEL Judge 58