FDA staff say Moderna flu shot data support use in seniors

FDA staff reviewers said Moderna’s flu vaccine candidate may be strong enough to support use in adults 65 and older, putting the company a step closer to a U.S. decision before the next flu season. The agency’s briefing documents said the shot generated an immune response that may support effectiveness in seniors, and that it showed superior relative vaccine efficacy versus a standard-dose flu vaccine in adults 50 to 64.

The stakes are highest for older adults, who face the greatest risk of severe influenza, hospitalization and death. But Moderna’s filing for people 65 and older rests mainly on immunogenicity data against a standard-dose vaccine, not against the higher-dose flu shots that the Centers for Disease Control and Prevention and its advisers preferentially recommend for this age group. CDC evidence reviews say high-dose inactivated flu vaccines contain four times the antigen dosage of standard-dose inactivated vaccines, which is why the choice of comparator has become a central issue.

The next formal test comes on June 18, 2026, when the Food and Drug Administration’s Vaccines and Related Biological Products Advisory Committee meets in open session to discuss and make recommendations on the safety and effectiveness of MFLUSIVA, Moderna TX Inc.’s mRNA influenza vaccine, for people 50 years and older. Moderna is seeking regular approval for adults 50 to 64 and accelerated approval for adults 65 and older, a split pathway that underscores how differently regulators may view immune-response data for younger and older patients.

The review marks a sharp turn from February, when the FDA issued a refusal-to-file letter on Moderna’s investigational seasonal flu vaccine, mRNA-1010, and said it would not begin review. Moderna then requested a Type A meeting, amended its submission and won acceptance of the filing for review on February 18, 2026. Former FDA officials had criticized the earlier study design, arguing that older patients should have been compared with the high-dose control used in routine care.

The broader regulatory backdrop also matters. FDA leadership under Marty Makary and Health Secretary Robert F. Kennedy Jr. has taken a more skeptical stance toward some vaccines, especially mRNA-based products, making the staff briefing a notable signal that Moderna’s data have cleared at least one important hurdle. Moderna shares rose 6% after the briefing documents became public, suggesting investors saw the review as a meaningful improvement in the company’s odds, even though the advisory vote and final FDA decision still lie ahead.