FDA Approves First mRNA Flu Vaccine for Older Adults Amid Seasonal Readiness Concerns
The U.S. Food and Drug Administration has approved mFlusiva, Moderna’s first mRNA-based seasonal influenza vaccine, for adults 50 and older. The approval makes mFlusiva the first FDA-approved mRNA flu vaccine in the United States.
The FDA approved mFlusiva through two pathways. Adults ages 50 to 64 received traditional approval based on clinical efficacy data. For adults 65 and older, the agency granted accelerated approval based primarily on immune-response data compared with a high-dose flu vaccine. Moderna must complete a post-approval study to verify the vaccine’s clinical benefit in that age group.
The FDA’s review examined a Phase 3 study involving more than 40,000 adults ages 50 and older. Compared with a standard-dose flu vaccine, mFlusiva showed 26.6% greater relative vaccine effectiveness against laboratory-confirmed influenza-like illness during one flu season. The agency cautioned that results from a single season may not predict performance during future seasons, when circulating strains can differ.
That distinction matters as older adults and caregivers plan for the 2026–2027 flu season. Adults 65 and older remain among those at greatest risk for serious influenza complications, and the CDC recommends annual flu vaccination for everyone six months and older, with certain vaccine formulations preferentially recommended for older adults.
The FDA review also found that side effects were more common with mFlusiva than with comparator vaccines. Injection-site pain, fatigue, headache, muscle aches and chills were generally mild to moderate and lasted about two days. The review noted that data remain limited for very frail and immunocompromised adults.
For now, eligible adults should ask a doctor or pharmacist which flu vaccine best fits their age, health history and seasonal needs. Bring questions about timing, prior reactions and other vaccines.
Check the FDA’s mFlusiva approval information, and share with your neighbors: will a new mRNA option change how you prepare for flu season?
