A.T. v. HHS - HPV, narcolepsy with cataplexy (2022)

On March 29, 2016, A.T., a minor at the time, through her mother, filed a petition under the National Childhood Vaccine Injury Act. The petition alleged that her second dose of the Gardasil Human Papillomavirus (HPV) vaccine, administered on May 1, 2013, caused or alternatively, significantly aggravated her narcolepsy with cataplexy.

Petitioner later amended her claim to allege only significant aggravation. The case was litigated as an "off-Table" claim, requiring proof of actual causation and significant aggravation.

Petitioner was born on March 27, 1999, making her approximately 14 years old at the time of the vaccination. Her medical history prior to vaccination included minor issues such as congenital cataract and obstructive sleep apnea.

She received her first HPV vaccine on April 2, 2012. Leading up to her May 1, 2013 vaccination, petitioner experienced increasing symptoms of sleep disruption, daytime sleepiness, leg buckling, falls, slurred speech, and gait difficulties, with onset approximately four to six weeks prior to her hospitalization on May 11, 2013.

Ten days after her second HPV vaccine, on May 11, 2013, she was hospitalized with complaints of sleeplessness, weakness, twitching, and slurred speech. Medical evaluations during her hospitalization included normal CT and EEG results, an inconclusive MRI, and a normal MRA.

She was seen by multiple specialists, including neurologists and infectious disease physicians. Her presumptive diagnosis was narcolepsy, and she was treated with intravenous immunoglobulin.

Lab results later indicated she had the HLA DQB1*0602 gene and low hypocretin, consistent with narcolepsy. Petitioner's mother provided conflicting accounts regarding the onset of symptoms, initially suggesting symptoms began two weeks before the May 1, 2013 vaccination, but later asserting that symptoms worsened significantly after the vaccination and that there was nothing wrong with her daughter on May 1, 2013.

Petitioner's expert, Dr. Lawrence Steinman, proposed a theory of molecular mimicry, suggesting that components of the Gardasil vaccine mimic hypocretin and its receptor, triggering an autoimmune response that aggravated narcolepsy.

He identified homologies between HPV proteins and hypocretin pathway components using BLAST searches. Respondent's experts, Dr.

Maryann Deak and Dr. J.

Lindsay Whitton, challenged Dr. Steinman's theory.

Dr. Deak, a neurologist and sleep medicine specialist, argued that the evidence did not support a causal link, citing the typical progression of pediatric narcolepsy, the lack of definitive evidence for autoantibodies in narcolepsy, and the absence of a statistically significant epidemiological association between the HPV vaccine and narcolepsy.

Dr. Whitton, a virologist and immunologist, criticized Dr.

Steinman's methodology, particularly his reliance on sequence homology without evidence of immune response and cross-reactivity, and argued that homologies are common and not necessarily biologically significant. Both respondent's experts pointed to epidemiological studies, including the Arnheim-Dahlstrom et al. study, which found no significant association between the HPV vaccine and narcolepsy.

Special Master Daniel T. Horner reviewed the extensive expert reports and medical records.

He found that petitioner failed to establish a medically probable theory of causation, specifically that Dr. Steinman's molecular mimicry theory, based on BLAST searches for sequence homology, was not sufficiently supported by evidence of immune response or cross-reactivity to establish causation.

He also found that the epidemiological evidence did not support a link between the HPV vaccine and narcolepsy. Furthermore, Special Master Horner determined that petitioner's condition's progression was consistent with the typical, insidious onset of pediatric narcolepsy and did not constitute a "significant aggravation" caused by the vaccine, noting that symptoms suggestive of cataplexy were present prior to vaccination.

The Special Master concluded that petitioner had not met her burden of proof under the six-part Loving test for off-Table aggravation claims. Therefore, the petition was denied.

Petitioner was represented by Danielle Strait of Maglio Christopher & Toale, P.A., and respondent was represented by Catherine Stolar of the U.S. Department of Justice.

The decision was issued on January 13, 2022.