Timothy Riese v. HHS - Tdap, ulcerative colitis and cavernous venous thrombosis (2025)

Timothy Riese, an adult, received Hepatitis A and Tdap vaccines on July 17, 2017. Approximately one to two weeks later, he began experiencing symptoms of ulcerative colitis, including bloody diarrhea, abdominal pain, and fatigue.

His condition progressed, leading to a diagnosis of severe ulcerative colitis. He also developed cavernous venous thrombosis, which was considered a complication of his ulcerative colitis.

Mr. Riese presented medical records and expert reports from a gastroenterologist and an immunologist, arguing that the Hepatitis A vaccine caused his ulcerative colitis through a molecular mimicry mechanism.

Respondent's experts contested this, arguing that the timing and presentation of the ulcerative colitis were inconsistent with vaccine causation and more aligned with the natural history of the disease. The Special Master found that Mr.

Riese had presented a sound and reliable theory, supported by evidence of molecular mimicry between the Hepatitis A vaccine and tropomyosin, a known auto-antigen in ulcerative colitis. The court determined that the Hepatitis A vaccine was a cause-in-fact of Mr.

Riese's ulcerative colitis and cavernous venous thrombosis. Entitlement to compensation was granted, with a separate order to follow for damages.