The FDA in February briefly refused to review Moderna’s flu vaccine, citing trial inadequacies, but reversed course a few days later. A verdict is expected by Aug. 5.
In back-to-back votes on Thursday, the FDA’s independent advisory panel for vaccines expressed their strong support for Moderna’s mRNA-based flu vaccine, which the company is proposing for use in older adults.
The vote is a “big win” for Moderna, William Blair told investors in a Thursday note, adding that flu forms part of the company’s “revenue growth goals beginning in 2027.” The FDA isn’t required to follow the recommendation of its advisors, but according to an analysis by Jefferies presented in a Thursday note, the agency did so 84% of the time from 2020 through 2025.
The FDA’s Vaccines and Related Biological Products Advisory Committee voted 9–0 in favor of full approval for Moderna’s shot mFlusiva to prevent flu in adults 50 through 64 years of age. The advisers returned a similar unanimous vote recommending the accelerated approval of the mRNA vaccine in people 65 years and older.
“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,” Hayley Gans, clinical professor at Stanford Medicine Children’s Health, said during the meeting in explanation of her vote.
In particular, Gans pointed to the broader benefits of Moderna’s technology. “I think that this particular platform adds exciting ways that we can move our vaccines into the future,” she said.
Moderna’s shares have risen 28% to $63.96 since the meeting’s briefing documents were released earlier this week. The stock ended Thursday up 3.5%.
The strong backing from the FDA advisers is a notable contrast to how previous FDA leadership regarded Moderna’s application. In February, the agency slapped the mFluvisa package with a refusal-to-file (RTF) letter, declining to even grant the submission a review. Vinay Prasad, former director of the Center for Biologics Evaluation and Research, had a strong hand in this decision, writing in a letter to Moderna that the company’s pivotal study used a control group that “does not reflect the best-available standard of care.”
The regulator quickly reversed course and days later accepted Moderna’s application for review. A decision is expected on Aug. 5.
At the end of April, Prasad left the FDA, ending a controversial and tumultuous term marked by reports of him interfering with drug reviews and fostering a toxic workplace.
Prasad’s exit, as it turned out, triggered a high-profile exodus at the regulator, including former Commissioner Marty Makary, who at many points came to the defense of Prasad—at one point even reportedly playing a heavy role in bringing Prasad back after he originally got the boot in July 2025. Makary had once called Prasad a “genius.”
But without pressure from Prasad and Makary, the FDA appears to have a largely positive view of Moderna’s mFluvisa. In a briefing document published earlier this week, the reviewers flagged a few uncertainties with the company’s submission—including the lack of data in immunocompromised and frail adults—but overall said that the package “met all prespecified sequential success criteria.”
The unanimous adcomm votes could put Moderna in a better position to meet its goal of breaking even in 2028—which had previously been imperiled by the FDA’s RTF letter. The company has attributed to mFluvisa a potential revenue opportunity of $1 billion, which could help shore up the company’s balance sheet. Moderna has been bleeding money for several quarters now, including a $2.8 billion loss last year.
