FDA approves first mRNA flu vaccine for adults 50 and older

FDA has approved Moderna’s mFLUSIVA (influenza vaccine, mRNA) for adults aged 50 years and older, marking the first mRNA-based influenza vaccine approved in the US. It is indicated for prevention of influenza caused by influenza A subtypes and influenza B strains represented in the vaccine.

Influenza vaccines are updated every year to match the strains expected to circulate. Much of the US flu vaccine supply is still made using eggs, but mFLUSIVA does not require growing vaccine viruses in eggs. The mRNA platform could allow vaccine strains to be updated more quickly as flu strains change and avoids egg-related changes that can sometimes affect how closely a vaccine matches circulating viruses.

Moderna expects mFLUSIVA to be available in the coming weeks for the 2026-2027 respiratory virus season.

Approval in adults aged 50 to 64 was supported by a phase 3 trial involving 40,805 adults aged 50 and older across 11 countries. Laboratory-confirmed influenza-like illness occurred in 2.0% of mFLUSIVA recipients versus 2.8% of those receiving a standard-dose influenza vaccine, corresponding to 26.6% relative vaccine efficacy.

For adults aged 65 and older, the FDA granted accelerated approval based on immune response data from a separate trial of 2,992 adults that compared mFLUSIVA with a high-dose inactivated influenza vaccine. Effectiveness in this age group was also supported by a descriptive analysis from the larger phase 3 trial. Continued approval for adults 65 and older may depend on confirmation of clinical benefit in a postmarketing trial.

The phase 3 program identified no major safety concerns. Reported adverse effects included injection-site pain and tenderness, fatigue, headache, muscle and joint pain, chills, nausea or vomiting, and fever.

For now, mFLUSIVA gives clinicians another influenza vaccine option for adults 50 and older rather than replacing existing vaccines. Its broader significance may be as a new way to develop and update seasonal flu vaccines—an advantage that will become clearer as effectiveness is evaluated across multiple influenza seasons.

Source: Moderna. (2026 Aug 5). FDA approves mFLUSIVA (mRNA-1010) for influenza prevention in adults aged 50 years and older