FDA Approves Moderna's mRNA Flu Vaccine for Older Adults
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- The FDA approved Moderna's mRNA influenza vaccine, marketed as mFlusiva, for adults ages 50 and older — the first licensed flu shot built on messenger RNA technology.
- The approval reversed Vinay Prasad's February "refusal-to-file" notice, which had overruled career FDA staff; that decision was reversed within a week after Moderna disclosed it, and Prasad left the FDA at the end of April.
- Moderna received standard approval for adults 50-64 and accelerated approval for adults 65+, contingent on a Phase 4 post-licensure trial comparing mFlusiva to existing high-dose or adjuvanted flu vaccines recommended for older adults.
- In adults 50-64, vaccine recipients were 27% less likely to contract test-confirmed influenza than those who got a standard-dose comparator; safety profiles were similar, though mFlusiva produced substantially more — mostly mild, one-to-two-day — side effects.
- The FDA's vaccine advisory committee (VRBPAC) voted unanimously in June that the vaccine's benefits outweigh its risks.
- mFlusiva is also under regulatory review in the EU, Canada, and Australia, with additional country submissions planned this year.
Why it matters: Moderna's mFlusiva enters a crowded U.S. flu market with an mRNA manufacturing edge: production in weeks rather than the months required for egg- or cell-based shots, enabling strain selection closer to flu season and faster pandemic response. For adults 65+, Moderna still owes the FDA Phase 4 head-to-head data against the preferentially recommended high-dose vaccines already standard for that group.
