FDA Approves Moderna's mFlusiva, First mRNA Flu Vaccine, for Adults 50 and Older
The FDA approved Moderna's mFlusiva, the first mRNA-based flu vaccine, for adults 50 and older. Full approval covers ages 50-64; accelerated approval covers 65+. Moderna expects availability later this year, pending CDC recommendation.
The Food and Drug Administration has approved a new kind of flu vaccine for older people, the first made with the same mRNA technology that was key to ending the COVID-19 pandemic, manufacturer Moderna said. The shot, named mFlusiva, is intended for adults age 50 or older. Moderna said the FDA granted full approval for mFlusiva's use in people ages 50 to 64, and accelerated approval for people 65 or older.
Approval in the 50-to-64 age group was based on a study of 40,000 people that found 27% fewer flu cases among people who got the new shot compared with those who got a different common flu vaccine brand. For people 65 or older, the FDA granted accelerated approval based on a smaller study showing mFlusiva generated a strong immune response compared with an existing high-dose vaccine for seniors, while Moderna conducts an additional study. Moderna's data showed no major safety issues although the shot did cause some temporary reactions including injection site pain, fever, headache, tiredness and aches that occurred somewhat more than with today's flu shots.
The approval caps off a far from straightforward regulatory journey. In February 2026, the FDA issued a rare refuse-to-file letter, with the agency citing concerns about the standard dose flu shot used in the comparison group. Moderna's stock slumped by more than 10% at the time. A week after the refusal-to-file was published, the FDA accepted an amended application after meeting with Moderna. In June, the FDA's Vaccines and Related Biological Products Advisory Committee voted unanimously that the benefits of Moderna's jab outweighed its risks across both age groups.
On the day the approval was announced, Moderna shares rose 1.77% to $58 at market open on 6 August, compared to a pre-announcement market close of $56.99. The approval marks Moderna's fourth FDA-approved vaccine. The company said it expects some of its new version to be available soon at select retailers. In February, the company reported an adjusted loss of $2.11 per share and revenue of $678 million, beating analysts' estimates. Moderna shares are up more than 55% since the start of 2026.
Moderna will now require Centers for Disease Control and Prevention recommendation for the shot to be used in national immunisation programmes in upcoming flu seasons, with the next Advisory Committee on Immunization Practices meeting scheduled for mid-October.
Flu vaccines must be updated annually to best match circulating strains of the virus. Vaccines made with mRNA technology are faster to manufacture than other types, and experts say this additional option might help if the shape-shifting flu virus mutates in a way that requires suddenly brewing new doses. While there already are multiple flu vaccine options in the U.S., including three specifically recommended for people age 65 or older, tens of thousands of Americans die from influenza every year and older adults are among the most vulnerable. The approval comes after a period of heightened vaccine scrutiny, with the health secretary a prominent critic of mRNA technology. Under his leadership, the Department of Health and Human Services cancelled $500 million worth of federally funded mRNA contracts in August 2025.