Christopher Demore v. HHS - Influenza, myasthenia gravis (2025)

Christopher Demore, a 67-year-old man, received an influenza vaccine on October 2, 2018. Approximately two weeks later, he developed double vision, which progressed to other stroke-like symptoms.

He was eventually diagnosed with myasthenia gravis, a neurological condition, which both parties' experts agreed was the correct diagnosis. Mr.

Demore alleged that the flu vaccine caused his myasthenia gravis and filed a petition for compensation under the National Vaccine Injury Compensation Program. He argued that the vaccine caused his injury through a theory of molecular mimicry, supported by expert reports.

The Secretary of Health and Human Services opposed the claim, relying on expert reports that questioned the causal link. The Special Master denied the petition, finding that Mr.

Demore failed to establish by a preponderance of the evidence a persuasive medical theory connecting the flu vaccine to myasthenia gravis. The Special Master noted that the evidence, including an epidemiological study, tended to undermine the claim that the flu vaccine causes myasthenia gravis, and that the proposed analogies were not sufficiently persuasive.

Mr. Demore sought review of this decision in the Court of Federal Claims, arguing that the Special Master applied an incorrect legal standard by requiring more than mere plausibility for the medical theory.

The Court affirmed the Special Master's decision, holding that the correct standard of proof is a preponderance of the evidence, not mere plausibility, and that the Special Master correctly applied this standard. The Court found that Mr.

Demore had not met his burden of proof on the first Althen prong (medical theory) and therefore could not receive compensation.