FDA will review Moderna’s revised mRNA flu vaccine after talks

The Food and Drug Administration said it will accept and review a revised biologics license application for Moderna’s experimental mRNA influenza vaccine, mRNA-1010, after a Type A meeting between the agency and the company. The agency set Aug. 5, 2026, as a target date for completing its review, a timetable that could put the shot in play for the 2026–2027 flu season if regulators clear it.

Moderna told regulators it is seeking full approval for adults 50 to 64 and accelerated approval for people 65 and older, and has proposed a post-marketing requirement to conduct an additional study in older adults. “We appreciate the FDA’s engagement in a constructive Type A meeting and its agreement to advance our application for review,” Stéphane Bancel, Moderna’s chief executive officer, said in the company statement. “Pending FDA approval, we look forward to making our flu vaccine available later this year so that America’s seniors have access to a new option to protect themselves against flu.”

The reversal follows an earlier regulatory setback in early February, when the agency initially declined to accept Moderna’s application. The refusal-to-file letter, published in mid-February, prompted an immediate market reaction and drew sharp scrutiny from both industry and federal officials. Moderna shares fell about 2 percent after the initial letter was published, then climbed roughly 6 percent on the day the agency agreed to review the revised filing; intraday Nasdaq trading showed the stock at $46.48, up 5.8 percent at one point.

Regulators and company officials have offered differing explanations for the dispute. The FDA raised concerns that Moderna should have administered a higher-strength vaccine to older participants in the control group of its pivotal trial and that the company did not follow earlier agency guidance, a point highlighted by FDA leadership. At a press briefing last week a senior FDA official described Moderna’s trial as a “brazen failure,” an assessment that underscored the seriousness of the agency’s earlier objections. Moderna has disputed the agency’s characterization and said the refusal was inconsistent with prior feedback.

The agency’s Center for Biologics Evaluation and Research will lead the review, and Moderna’s revised regulatory pathway centers on age-stratified approvals that would hinge on post-marketing commitments to generate additional evidence in seniors. The company’s proposal recognizes the different evidentiary bar FDA applies for accelerated approval in older adults and aims to resolve gaps the agency flagged.

Public health experts and vaccine scientists expressed frustration at the opaque exchange between regulator and manufacturer. Michael Osterholm, director of the University of Minnesota Center for Infectious Disease Research and Policy, said the reversal raises questions about consistency in regulatory decision making. “We don’t have any idea why they reversed course,” he said, adding that developers need clear guidance if the United States is to maintain a predictable vaccine development environment.

The case arrives amid heightened political scrutiny of mRNA technology from some critics and officials, and it highlights the trade-offs regulators must weigh between speed, evidence and post-approval monitoring. With the August target date in place, the FDA and Moderna now face a compressed window to resolve scientific and procedural issues that will determine whether an mRNA flu vaccine reaches older Americans for the next influenza season.