Caroline Walker v. HHS - Influenza, multiple sclerosis (2022)

Caroline Walker alleged that an influenza (flu) vaccination significantly aggravated her previously undiagnosed multiple sclerosis (MS). She received the flu vaccine on September 24, 2015.

Within approximately 39 hours, she developed numbness and tingling in her hands and feet, which progressed over the next six days. An MRI on October 1, 2015, showed a non-enhanced lesion, indicating it predated the vaccination.

Based on this and other clinical manifestations, she was diagnosed with MS. The court considered two main issues: the timing of her symptoms and the proposed mechanism of causation.

The court found that the approximately 39-hour onset was too rapid for the vaccine to have initiated the cascade of events leading to MS, especially given that a non-enhanced lesion predated the vaccination. Furthermore, the proposed theory involving complement as a mechanism for vaccine-induced MS aggravation was found unlikely, with expert testimony suggesting complement plays a role in propagating existing disease rather than initiating it, and that B cell activation, a necessary step, takes several days.

A treating doctor also indicated the vaccine was unlikely to have contributed to her MS. Ultimately, Ms.

Walker failed to meet her burden of proof for a significant aggravation claim, and her petition for compensation was denied. The petition was filed on February 28, 2018, and the decision denying compensation was issued on September 27, 2022.