FDA advisory panel unanimously backs Moderna's mRNA flu shot for older adults after earlier agency rejection

The committee's vote

The FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC) voted unanimously on Thursday to recommend Moderna's mRNA influenza vaccine, mFlusiva, for adults 50 and older. It was the panel's first review of a new vaccine application since 2023. The vote arrived despite sustained criticism of vaccines from the Trump administration, including Secretary of Health and Human Services Robert F. Kennedy Jr., who last year withdrew nearly $500 million in mRNA vaccine contracts.

“It's such a breath of fresh air, considering what we've gone through with Robert F. Kennedy Jr.”

Clinical data

Results from a Phase 3 trial enrolling over 40,000 adults aged 50 and older showed the mRNA vaccine was about 27 percent more effective against seasonal flu than a standard flu shot. A separate, smaller study in nearly 3,000 people 65 and older indicated the shot generated flu-fighting antibodies on par with a high-dose vaccine recommended for that age group. FDA staff reviewers said in briefing documents that immune-response data might support effectiveness in the older cohort, though they noted that very frail older adults and immunocompromised people were excluded from the trials.

“Every year when we approve flu vaccines, we don't have efficacy data. So I think the question will be whether or not they thought that the immunogenicity study was big enough.”

Agency drama

In February, the FDA under then-vaccine chief Vinay Prasad refused even to review Moderna's application. Prasad argued the trial should have used a high-dose flu vaccine as the control for patients 65 and over. After public criticism, the agency reversed course two weeks later. Prasad and FDA Commissioner Marty Makary later left the agency. Acting Commissioner Kyle Diamantas has since moved to stabilize operations. The advisory committee then conducted its review with FDA staff scientists broadly supportive of the vaccine.

“I think that the studies that were presented today were very well conducted. They have very clear results that are very robust in terms of demonstrating that additional efficacy.”

A platform for the future

If the FDA follows the panel's advice, mFlusiva would become the first seasonal flu shot in the U.S. made with mRNA technology. Backers highlight that mRNA vaccines can be produced more quickly and reliably than conventional shots, an advantage for matching fast-changing flu strains and preparing for future pandemics.

“This particular platform adds exciting ways that we can actually move our vaccines to the future. The signals that we're seeing now are not putting people at risk and the benefits are actually large not only for this season, but for really what it can do for our vaccine platform.”

Moderna is seeking traditional approval for adults 50 to 64 and accelerated approval for those 65 and older, committing to run an additional study and submit more data in the older group if that approval is granted.