M.K. v. HHS - Tdap, systemic juvenile idiopathic arthritis (sJIA) (2025)
Case summary [AI summaries can sometimes make mistakes]
On January 28, 2022, Samantha and Brandon Klagenberg filed a petition on behalf of their minor child, M.K. He was 12 years old when he received tetanus, diphtheria, and acellular pertussis (Tdap) and meningococcal conjugate vaccines at a well-child visit on June 14, 2021.
He had no immediate reaction, but about two to three weeks later he developed a frightening illness that his family later connected to the vaccinations. By early July 2021, M.K. had fever, rash, vomiting, severe migratory joint pain, stiffness, and trouble walking.
His mother described excruciating pain, lethargy, nausea, and a limp. Emergency and pediatric records initially considered viral exanthem, infection, inflammatory disease, reactive arthritis, and juvenile idiopathic arthritis.
At UC Davis, physicians documented intermittent fevers, rash, joint pain, vomiting, knee and hip symptoms, and abnormal inflammatory labs. Pediatric rheumatologist Dr.
Angel Alberto Herrera Guerra ultimately treated the picture as systemic-onset juvenile idiopathic arthritis, while repeatedly noting that he did not think the Tdap vaccine caused it, though he could not absolutely rule timing out. M.K. later had knee swelling, steroid-responsive pain, joint injections, and continuing limits that affected school, sports, and ordinary childhood activities.
At hearing, M.K. and his parents described an active child who had played basketball and then lost a summer to pain, vomiting, weakness, and fear about his body. Petitioners' expert, rheumatologist Dr.
Eric Slavin, proposed that the vaccines triggered sJIA through immune dysregulation involving innate and adaptive immune responses, NLRP3/inflammasome activation, cytokines such as IL-1 beta and IL-18, aluminum adjuvant, and meningococcal polysaccharide stimulation. Respondent's experts, pediatric rheumatologist Dr.
Mindy Lo and immunologist Dr. Christine McCusker, disputed the vaccine theory, questioned the timing, and emphasized the lack of reliable evidence connecting these vaccines to sJIA.
Chief Special Master Brian H. Corcoran accepted that M.K. had sJIA but denied entitlement on October 3, 2025.
He found that petitioners had not established a reliable medical theory or a logical sequence of cause and effect under Althen prongs one and two. The ruling emphasized that the proposed mechanisms did not fit the clinical timing, that treating physicians did not support vaccine causation, and that the literature did not show Tdap or meningococcal vaccination can cause sJIA.
No compensation was awarded. Petitioners were represented by John Beaulieu of Siri & Glimstad, LLP.
Theory of causation
Tdap and meningococcal conjugate vaccines, June 14, 2021, age 12, alleged systemic juvenile idiopathic arthritis. DENIED. Petitioners' expert Dr. Eric Slavin proposed vaccine-triggered innate/adaptive immune dysregulation involving NLRP3/inflammasome cytokines, alum adjuvant, polysaccharides, and ASIA-like immune activation. Respondent experts Dr. Mindy Lo and Dr. Christine McCusker disputed causation, emphasizing lack of reliable evidence that Tdap/meningococcal vaccines cause sJIA, timing problems for the proposed immune mechanisms, and alternative post-infectious/reactive arthritis possibilities. Symptoms began around July 1-6, 2021 with fever, rash, vomiting, severe migratory joint pain, limping, knee swelling, elevated inflammatory markers, and later sJIA diagnosis by treating rheumatology, though the treating specialist repeatedly doubted vaccine causation. Chief Special Master Corcoran found sJIA but held Althen prongs one and two not met. Decision October 3, 2025. No award. Attorney John Beaulieu; respondent Dorian Hurley.
Source PDFs
USCOURTS-cofc-1_22-vv-00086