*Event date: August 5, 2026*

Approval brings mRNA technology to influenza prevention

The US Food and Drug Administration approved Moderna’s mFlusiva for people aged 50 and older on August 5, making it the first influenza vaccine using messenger RNA technology to receive the agency’s clearance. Moderna planned to have the vaccine available during the coming autumn flu campaign.

The decision extends a vaccine platform already associated with COVID-19 into seasonal influenza. Unlike conventional flu vaccines that may require the virus to be grown in eggs, an mRNA product uses genetic instructions selected for the targeted pathogen. That approach can shorten development: the process for mFlusiva takes about six weeks, compared with as much as six months for existing production methods, according to Time’s account of the approval.

That timing matters because flu vaccines are formulated ahead of each season. Experts assess which strains are likely to circulate and recommend targets for manufacturers, but the forecast does not always match the viruses that ultimately spread. A shorter production cycle could allow vaccine makers to choose strains closer to the start of a season, potentially improving the match.

Large study compared the shot with existing vaccines

Moderna submitted results from a randomized study involving more than 40,000 participants over 50. Each received either a single dose of mFlusiva or one of four existing influenza vaccines. On average, participants given mFlusiva were 27% less likely to develop laboratory-confirmed influenza-like illness than those who received a comparator vaccine. The study was published in the New England Journal of Medicine in May 2026, Time reported.

The vaccine’s route to review was not straightforward. In February, the FDA initially issued Moderna a refusal-to-file letter, arguing that the application lacked an appropriate control group and questioning whether the chosen comparators represented the best available care. The agency had sought data comparing outcomes in people aged 65 and older with higher-dose vaccines used for that group. Moderna said it supplied additional information.

After company scientists and executives met with the agency, Moderna pursued full approval for adults aged 50 to 64 and accelerated approval for those 65 and older, alongside plans for an additional study in the older population. The FDA then reversed course and agreed to review the application.

The authorization limits mFlusiva’s initial market to older adults. It also gives clinicians and patients in that age range another option as annual flu campaigns begin. Whether faster mRNA production will consistently yield a closer match to circulating strains will depend on future seasons, but the approval establishes a new technical route for making US influenza vaccines.