The flu shot goes mRNA: FDA approves Moderna's mFlusiva for adults 50 and older

The first flu vaccine built on mRNA technology wins FDA approval for adults 50 and older, arriving roughly 27% more effective than a standard shot in trials — and just in time for this fall's flu season.

The Food and Drug Administration has approved the first flu vaccine built on mRNA technology, clearing Moderna's mFlusiva for adults 50 and older and handing the COVID-era platform its first seasonal-vaccine win.

The approval spans two groups — adults 50 to 65 and those 65 and up — with Moderna required to run an additional clinical trial in the older cohort. In a late-stage study of more than 40,000 older adults across 11 countries, mFlusiva was about 27% more effective than a standard flu shot. The real selling point is speed: Moderna says it can select a strain and roll out doses in two to three months, compared with roughly six months for traditional flu shots — a faster turnaround that could let scientists better match whatever is actually circulating.

The path to approval wasn't smooth. The FDA initially declined to review the application this year before reversing course a week later, and its independent advisory committee voted unanimously in June to recommend the shot. The approval also lands amid broader skepticism of mRNA from Health and Human Services Secretary Robert F. Kennedy Jr., whose department has curtailed mRNA research funding. Moderna says mFlusiva will be available for this fall's flu season.

Sources: NBC News | FDA