FDA advisers back Moderna mRNA flu vaccine

A federal vaccine advisory panel unanimously recommended Moderna’s mRNA flu shot for adults 50 and older Thursday, moving the vaccine a step closer to becoming the world’s first approved messenger RNA vaccine for influenza.

The Food and Drug Administration’s Vaccines and Related Biological Products Advisory Committee voted 9-0 to recommend the shot, called mFlusiva, after a daylong review of safety and effectiveness data. The vote was the committee’s first review of a new vaccine application since 2023, NPR reported.

If the FDA approves the vaccine, it would still need a formal recommendation from the Centers for Disease Control and Prevention’s vaccine advisory committee before Americans could receive it. NBC News reported that the CDC committee has been blocked from convening by a federal judge. NPR reported that Health and Human Services Secretary Robert F. Kennedy Jr. disbanded that panel and that it remains unclear how recommendations would be made for the fall.

Moderna says the vaccine could be available for the next flu season if regulators approve and recommend it.

In a late-stage trial, mFlusiva was found to be about 27% more effective than a standard flu shot, NBC News reported. FDA reviewer Dr. Gauri Raval said during Thursday’s meeting that the vaccine “may offer greater efficacy than the standard dose comparator in preventing more severe influenza-associated illness[es].” The FDA found no “major safety issues or deficiencies,” according to NPR.

The committee recommended approval for adults ages 50 to 64 and adults 65 and older. For the older group, panel members said Moderna should be required to conduct an additional clinical trial after the vaccine reaches the market. The trial design drew scrutiny because Moderna compared its vaccine in adults 65 and up against a standard flu shot, even though the CDC recommends a high-dose vaccine for that age group. Moderna said the FDA had previously signed off on the trial design.

The FDA initially declined in February to review Moderna’s application, then reversed course after criticism. Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia and a former FDA advisory panel member, told NPR the reversal was unusual. “You can’t say, yes, go ahead, spend tens of millions of dollars, and then, when they present data, say, no, we’re not even going to look at this data,” he said.

Messenger RNA vaccines use genetic instructions to prompt the body to produce flu antigens and build immunity. Moderna wrote in its briefing materials that the vaccine “does not enter the cellular nucleus, does not interact with the genome … and does not persist in the body.”

Researchers and company officials said the technology could help address one of the persistent problems with seasonal flu vaccines: strain mismatch. Traditional flu shots require manufacturers to choose strains months before flu season, leaving time for the virus to evolve. Moderna said its mRNA shot could move from strain selection to rollout in two to three months, compared with about six months for traditional flu shots.

“The ability to tweak a flu vaccine later in the year than can be done with egg based vaccines may allow more up to date vaccines,” said Dr. Jesse Goodman, a former FDA chief scientist and infectious disease specialist at Georgetown University Medical Center.

Flu continues to cause a heavy toll in the United States. Dr. Lisa Grohskopf of the CDC told the panel there had been at least 32 million flu cases, 390,000 hospitalizations and 24,000 deaths in the 2025-2026 flu season, according to NPR. She also said “approximately 85% of those eligible for vaccination were not fully vaccinated against influenza.”

The review comes amid sharp criticism of mRNA technology from Kennedy, who has called the mRNA COVID shot “the deadliest vaccine ever made,” according to NBC News. Last year, HHS canceled or pulled back nearly $500 million in mRNA vaccine research contracts. FDA advisers and outside experts said Thursday’s public review focused on the evidence.

“I think that this platform adds exciting ways we can actually move our vaccines into the future,” said committee member Dr. Hayley Altman-Gans of Stanford University Medical Center.