FDA Reverses Decision, Will Review Moderna's mRNA Flu Vaccine After Initial Rejection

The Food and Drug Administration will consider whether to approve Moderna's new flu vaccine after all, resolving a dispute that had blocked the company's application for the first-of-its-kind shot. Moderna announced the change on February 18, 2026, about a week after revealing that the FDA's vaccine chief was refusing to review the new vaccine, made with Nobel Prize-winning mRNA technology.

The Food and Drug Administration's decision, made public on Feb. 10, 2026, to not review an application to approve Moderna's proposed mRNA-based flu vaccine set off a firestorm of criticism from public health experts. The decision sent Moderna's stocks soaring in a rebound from the earlier decision. Shares of Moderna Inc. rose more than 5% after the announcement in morning trading. Shares of Moderna added 6.5% at about $47 on the update.

The dispute centered over a 40,000-person clinical trial that concluded Moderna's new vaccine was more effective in adults age 50 and older than one of the standard flu shots used today. The clinical trial submitted by Moderna involved 40,000 people and showed the vaccine was more effective at preventing severe flu than standard inactivated virus offerings on the market. The study focused on adults 50 and older, but not those over 65.

In the FDA's rare "refusal to file" letter, vaccine director Dr. Vinay Prasad faulted the trial for not including another brand specifically recommended for people 65 and older. In declining the application originally, the FDA claimed that Moderna did not conduct an "adequate and well-controlled" study because it had not compared patients receiving its vaccine with patients receiving what the agency claimed to be "the best-available standard of care."

Moderna publicly objected. It said that while the FDA had recommended that approach, the agency ultimately agreed to the study's design — and that the company shared additional comparison data from a separate trial that used a high-dose shot for older people. The Massachusetts-based pharmaceutical company expressed shock, saying the agency had agreed to the study design before it was conducted. It acknowledged that regulators pushed for those 65 and older to be the focus, but said the two parties settled on a separate data analysis that demonstrated safety for seniors. Nor did the FDA identify any safety concerns.

Moderna said it submitted comparisons showing that, even at a high dose, its mRNA flu shot was safe for those 65 and older. However, no head-to-head comparison was conducted in that age group using a brand-name alternative vaccine.

Moderna said Wednesday that in a compromise, it is seeking full approval for the vaccine's use in adults 50 to 64 and accelerated approval for those 65 and older, with an additional study once the shot is on the market. The dispute, centered entirely on age limits, was the source of the rejection. Now it appears Moderna has refiled, seeking approval for its flu vaccine for adults ages 50 to 64.

The FDA said it will review the vaccine for use by people age 50 to 64 under the standard review pathaway, which is how it evaluates most drugs. The agency's decision to review it now is effectively a reversal of that position, which was not based on any legal standard.

For people age 65 and older, the FDA said it will now review the vaccine through a long-standing program called "accelerated approval," which is used to more quickly review drugs that "treat serious conditions" and "fill an unmet medical need," and that show promise. Under this faster process, the law allows the FDA to consider different data than under a standard approval. Instead of looking at final results, a company can submit results that use a proxy measurement to reflect that a drug is likely to achieve its clinical goal.

This means that if the FDA approves Moderna's vaccine for this older age group, the company will have to conduct additional studies on it afterward. What's unusual, though, is that the agency typically suggests the use of the accelerated approval pathway much earlier in the process, not after a company submits its application.

The FDA has accepted Moderna's biologics license application (BLA) for review and assigned a Prescription Drug User Fee Act (PDUFA) goal date of August 5, 2026. The FDA is targeting a decision on the application by Aug. 5, and Moderna said it hoped to make the vaccine available later this year. If approved, mRNA-1010 would be available for US adults 50 and older, including those 65 and older, for the 2026/2027 flu season.

If approved, the vaccine would become the only mRNA flu vaccine available for older adults, though traditional flu vaccines would remain an option. There are no federal laws making flu shots compulsory, though some health care settings may require them for workers.

It also has applied for the vaccine's approval in Europe, Canada and Australia. Moderna has also submitted mRNA-1010 for review in Europe, Canada, and Australia, with additional submissions planned for 2026. The company expects the first potential approvals later this year, subject to ongoing regulatory assessments.

The review follows a Type A meeting between the company and the agency. The highly unusual public dispute was the latest sign of the FDA's heightened scrutiny of vaccines under Health Secretary Robert F. Kennedy Jr., particularly those using mRNA technology, which he has criticized before and after becoming the nation's top health official.

In the past year, FDA officials working under Kennedy have rolled back recommendations around COVID-19 shots, added extra warnings to the two leading COVID vaccines — which are made with mRNA technology — and removed critics of the administration's approach from an FDA advisory panel.

In February 2026, Moderna reported full-year 2025 revenue of US$1.94 billion and a net loss of US$2.82 billion. Even before the FDA's decision to reject the application, Moderna and other drugmakers were beginning to pare back investments in vaccines due to concerns about the approval process. Already, multiple vaccine manufacturers, including Moderna, have announced plans to scale back their investment in vaccine research and cut jobs.