FDA and Vaccine Regulation

The FDA’s CBER issued a refusal‑to‑file for Moderna’s investigational mRNA seasonal influenza vaccine, saying the Phase 3 trial was not “adequate and well‑controlled” because Moderna used a licensed standard‑dose comparator rather than the higher‑dose “best‑available” standard of care for older adults; Moderna says the agency did not object to the protocol when it was submitted in April 2024 or before the trial began in September 2024 and that 2024 guidance had indicated a standard‑dose comparator could be acceptable. A pre‑submission meeting in August 2025 flagged the comparator as a “significant issue” without warning of a possible refusal, and commentators have placed the decision in the broader context of recent vaccine‑policy changes at HHS, including removal of VRBPAC members, canceled mRNA vaccine contracts, narrowed COVID authorizations and removal of COVID shots from some immunization schedules.