The FDA has placed a clinical hold on Novavax's application for its COVID-19-Influenza combination and standalone influenza vaccine candidates following a report of a "serious adverse event."

The report involved motor neuropathy in a participant of the phase 2 trial conducted outside the U.S., according to an Oct. 16 news release from the company. The participant received the vaccine in January 2023 and reported the serious adverse event in September 2024, after the trial was concluded in July 2023.

Novavax Chief Medical Officer Robert Walker, MD,emphasized the company's commitment to safety, stating, "While we do not believe causality has been established for this serious adverse event, we are committed to working expeditiously with the FDA to resolve this matter."

Data from previous trials has not indicated any signals for motor neuropathy, and investigators have been notified about the clinical hold, the release said.