FDA approves Moderna's mRNA flu vaccine for adults 50 and older

The U.S. Food and Drug Administration granted approval on Aug. 5 for Moderna’s mFLUSIVA, the first influenza vaccine that uses messenger RNA technology, for adults 50 years of age and older. The decision follows a unanimous vote by an FDA advisory committee that the vaccine’s benefits outweigh its risks.

Clinical trials involving about 70,000 participants indicated that mFLUSIVA was roughly 27% more effective at preventing laboratory-confirmed influenza than standard inactivated flu vaccines and generated a stronger immune response in those 65 and older, while severe side effects remained rare. The panel’s chair, Anna Durbin of Johns Hopkins University, described the data as “excellent” and said the vaccine is “very, very promising.”

Unlike traditional egg-based or recombinant flu shots, which require months to produce and can suffer from strain mismatches, the mRNA platform delivers a genetic script that directs cells to produce a flu protein, allowing rapid redesign and manufacturing. Durbin noted that this speed could enable vaccines to be updated closer to the start of the flu season, potentially improving strain matching.

The vaccine will be available this fall as an additional option for older adults, though its distribution, pricing and uptake remain uncertain. Insurance coverage is expected, but availability may vary by pharmacy. Existing flu vaccines will continue to be offered, and the CDC’s advisory committee will assess real-world performance before recommending any changes to the standard of care.

Durbin said the upcoming 2026-27 flu season will provide the first post-licensure data, which will be critical to determine whether mRNA flu vaccines become a preferred choice over traditional formulations.