FDA Greenlights Review of Moderna’s mRNA Flu Shot After Application Amended

On Feb. 18, 2026, the U.S. Food and Drug Administration (FDA) agreed to review Moderna’s application for its mRNA influenza shot, known as mRNA-1010, after the company amended its submission to address regulatory concerns. The agency accepted the updated biologics license application and set a target action date of Aug. 5, 2026, allowing the shot to move into formal scientific review.¹

The FDA’s decision came after the agency issued a “Refusal to File” (RTF) letter on February 3, 2026, declining to review Moderna’s initial application. A press release by Moderna stated that company officials and FDA regulators held a formal “Type A” meeting to discuss the deficiencies identified in the original submission.²

According to the FDA, a Type A meeting is one that is necessary for an otherwise stalled product development program to proceed or to address an important safety issue. The agency designates these meetings for situations that require immediate attention so that regulators can resolve critical obstacles preventing progress.³ Following that meeting, Moderna restructured parts of its application in a way the agency determined satisfied its filing requirements.⁴

FDA Refused to Review Moderna’s Initial Application

The FDA issued an RTF letter in response to Moderna’s initial application for its mRNA influenza shot, meaning the agency would not begin a formal scientific review because it concluded the submission did not meet required standards. An RTF does not constitute a rejection based on safety or effectiveness findings. Instead, it indicates that regulators believe the application lacks necessary elements to proceed.⁵

The dispute centered on the design of Moderna’s Phase 3 clinical trial. The company conducted a study involving approximately 40,000 participants and compared mRNA-1010 to a licensed standard-dose influenza vaccine. However, the FDA objected to the control arm used in adults 65 and older, stating that the trial should have used what regulators consider the “best-available standard of care” for seniors in the United States, typically a high-dose influenza vaccine.⁶

FDA regulators concluded that using a standard dose comparator in seniors did not adequately reflect current clinical practice for that age group. Therefore, the agency determined that the application, as submitted, did not meet evidentiary expectations for evaluating the mRNA shot in older adults.⁷

How Moderna Addressed the FDA’s Filing Criteria

After receiving the RTF letter, Moderna worked to restructure its submission to resolve the agency’s concerns. The company separated its approval strategy by age group in the amended application. Under the revised filing, Moderna will pursue traditional approval for adults ages 50 to 64, meaning the mRNA shot would need to meet the FDA’s standard approval requirements for that group. For adults 65 years of age and older, the company will seek accelerated approval, a pathway that allows earlier authorization while requiring additional follow-up studies, and conduct a post-marketing confirmatory study to further evaluate the shot’s effectiveness in that population.⁸

This revised pathway directly addressed the FDA’s concern about how older adults were evaluated in the Phase 3 trial. By committing to additional research in seniors after potential approval, Moderna created a regulatory framework that satisfied the FDA’s filing standards.⁹

According to Moderna, mRNA-1010 has now been accepted for regulatory review in the United States, as well as in Europe, Canada, and Australia, with additional submissions planned in 2026. The company stated that it expects the first potential approvals for the mRNA influenza shot in 2026, pending the outcome of ongoing regulatory reviews in those regions.¹⁰

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