FDA Schedules June 18 Advisory Panel for Moderna mRNA Flu Vaccine; MRNA Stock Falls 5.5%

On May 21, 2026, the FDA published a Federal Register notice scheduling an advisory committee hearing for June 18, 2026, to review Moderna's mRNA-1010 (MFLUSIVA) seasonal influenza vaccine for adults aged 50 and older. The move triggered a roughly 5.5% decline in Moderna's stock as markets interpreted the rare advisory panel as an additional layer of scrutiny beyond the standard review. The PDUFA goal date for a US approval decision remains August 5, 2026. If approved, mRNA-1010 would be the first mRNA vaccine for seasonal influenza authorized in the United States. The advisory panel is unusual for flu vaccines and reflects the FDA's complex posture toward Moderna's application: in February 2026, the agency issued a refusal-to-file letter citing concerns that the Phase 3 trial compared mRNA-1010 against standard-dose rather than high-dose or adjuvanted flu vaccines; it reversed course within days under public and institutional pressure, accepting the application. The adcomm will allow independent experts to assess the trial design, efficacy data (relative vaccine efficacy of 26.6% over standard-dose comparator in a 40,000+ person Phase 3 trial), and whether the benefit-risk profile justifies authorization for seasonal use.