FDA Advisors Unanimously Back Moderna's mRNA Flu Vaccine

Independent advisors for the Food and Drug Administration on Friday voted 9–0 in support of approving Moderna’s seasonal mRNA flu vaccine, which a Trump appointee at the agency initially tried to block from even being reviewed.

In an all-day meeting, members of the FDA’s advisory committee—known as VRBPAC for Vaccines and Related Biological Products Advisory Committee—pored over data and presentations on the vaccine, which is dubbed mRNA-1010 and branded as mFlusiva. The presentations included a review from FDA scientists, which was supportive of the vaccine.

Data from a Phase 3 trial including over 40,000 adults age 50 and older found the mRNA vaccine was around 27 percent more effective against seasonal flu than a standard flu shot. A smaller Phase 3 trial, involving data from nearly 3,000 people age 65 years and older, showed the shot produces stronger immune responses than a high-dose flu vaccine, which is recommended for this age group. The safety profile of the vaccine was also generally good.

“I think that the studies that were presented today were very well conducted,” VRBPAC voting member Flor Munoz-Rivas, a pediatric infectious disease expert at Baylor College of Medicine, said after the vote. “They have very clear results that are very robust in terms of demonstrating that additional efficacy.”

She also expressed enthusiasm for the agile mRNA platform for the flu vaccine, which is based on the same platform Moderna used to develop its mRNA COVID-19 vaccines. In addition to the better efficacy, it allows for “rapid development of the vaccines in regular seasonal flu activity” and makes us “better prepared for emerging strains or pandemic strains in the future,” she said.

Fellow voting member Hayley Gans, a pediatric infectious disease expert at Stanford University, agreed. “I think that this particular platform adds exciting ways that we can actually move our vaccines to the future,” she said. “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. … This one has the potential to really move us in a modern direction.”

FDA drama

The outcome today is in stark contrast to a few months ago, when Trump official Vinay Prasad was overseeing vaccines at the FDA. In a shocking decision in February, Prasad rejected Moderna’s filing, refusing to even review the vaccine. Prasad claimed that the large vaccine trial was not “adequate and well-controlled” because it did not compare efficacy to a high-dose vaccine in people 65 and older. Instead, Moderna used the smaller trial to compare immune responses of mRNA-1010 to a high-dose vaccine—which was a plan the FDA had previously agreed would be acceptable.

Moderna was blindsided by the refusal, which Prasad issued over the objections of FDA scientists and career officials. Amid widespread outcry, the FDA reversed the decision the next week, agreeing to review the vaccine. Around the same time, Prasad was also behind the rejection of a closely watched gene therapy for Huntington’s disease made by UniQure, which was widely criticized and called “truly evil” by a former FDA official.

Prasad was pushed out of FDA at the end of April amid a string of decried decisions and controversies. Prasad’s decision on UniQure’s gene therapy was reversed on Wednesday.

Moderna released a statement saying it was pleased with today’s outcome.

“We appreciate the thoughtful review by the members of VRBPAC and their recognition of the clinical evidence supporting mRNA-1010,” Moderna CEO Stéphane Bancel said in the statement. “We believe mRNA-1010 has the potential to provide an important new option for seasonal flu prevention and further demonstrate the versatility of our mRNA platform. We look forward to continuing to work with the FDA as it completes its review.”

Next steps

While unanimous support from the advisors is a positive sign for the vaccine’s fate, the FDA ultimately decides whether to grant approval. The agency has set a deadline for a decision by August 5.

Moderna has previously said it is aiming to release the vaccine later this year, pending approval.

A further hurdle will be getting a recommendation from the Centers for Disease Control and Prevention. Newly FDA-approved vaccines would first be reviewed by the CDC’s advisory committee—the Advisory Committee on Immunization Practices (ACIP)—which would vote on recommendations for use that it thinks the CDC should adopt. Having recommendations from ACIP and CDC mean that almost all commercial insurance providers and federal programs would be required by law to cover the vaccine at no cost.

However, ACIP is effectively defunct after a federal judge issued a temporary injunction that blocked almost all of the allies anti-vaccine Health Secretary Robert F. Kennedy Jr. installed on the committee. The judge ruled that Kennedy’s handpicked advisors were appointed improperly. Like Kennedy, many of them hold anti-vaccine views and are also openly hostile to mRNA technology.

The US Department of Health and Human Services is now appealing the injunction on an expedited schedule that will stretch at least into July.