Moderna’s mRNA flu shot wins FDA approval

The US Food and Drug Administration granted approval on 5 August to Moderna’s mRNA-based flu vaccine, mFLUSIVA, for adults aged 50-64, with accelerated approval for adults aged 65 and older. Moderna says the shot will be available “in a few weeks” for the 2026-27 flu season in the United States, while regulators in the European Union, Canada and Australia are also reviewing it.

Researchers said the mRNA platform could help manufacturers reformulate vaccines more quickly as influenza strains change. In tests on more than 20,000 adults, 2% of recipients developed laboratory-confirmed flu, compared with 2.8% among people given a standard dose of a non-mRNA comparator vaccine. Clinical studies found a 26.6% relative reduction in confirmed flu cases against a standard influenza vaccine, using antigens from the three 2024-25 strains recommended by the World Health Organization.

Safety data showed mFLUSIVA was generally well tolerated, with mostly mild to moderate side effects such as injection-site pain, fatigue and headache. Side effects were more common than with the standard-dose comparator, and injection-site pain was reported more than twice as often. Moderna has agreed with the FDA to run a confirmatory phase IV trial comparing efficacy with an enhanced vaccine in people aged 65 and older.