FDA

The FDA approved Moderna’s mRNA-based flu vaccine this week, clearing the way for the first influenza shot built on the same technology used in COVID-19 vaccines — a regulatory turnaround that seemed unlikely just six months ago, after the agency initially refused to even review the product. What Got Approved The vaccine, branded mFlusiva, received standard FDA approval for adults ages 50 to 64 and accelerated approval for adults 65 and older, with the latter approval contingent on Moderna completing an additional postmarketing study to confirm clinical benefit in that higher-risk age group. In a late-stage clinical trial involving more than 40,000 participants, mFlusiva demonstrated roughly 27% greater effectiveness against influenza-like illness compared to a standard-dose flu vaccine — a meaningful edge for a population that faces disproportionately severe complications, including pneumonia, from seasonal flu. Moderna CEO Stéphane Bancel called the approval a milestone for the company’s broader platform. “Flu remains a significant public health challenge, and mFLUSIVA provides an important new option for America’s seniors,” Bancel said in a statement, adding that the approval “reflects the ongoing potential of our mRNA platform to help address important public health challenges through continued scientific innovation.” A Bumpy Road to Approval The path here wasn’t straightforward. Back in February, then-FDA biologics chief Vinay Prasad issued a rare “refusal-to-file” notice, overturning career staff’s recommendation and declining to even review the vaccine based on the data package Moderna had submitted — a decision some observers speculated may have been influenced by broader skepticism toward mRNA technology within the administration. Just two weeks later, after Moderna publicly disclosed both the rejection and its own frustration with the decision, the FDA reversed course and agreed to move forward with a review in time for the 2026-2027 flu season. Prasad left the FDA at the end of April. Once under formal review, the vaccine’s data made a strong impression: the FDA’s outside advisory panel, the Vaccines and Related Biological Products Advisory Committee, voted unanimously in June to recommend approval. One panelist, Dr. Flor Munoz-Rivas of Baylor College of Medicine, praised the rigor of the underlying research. “The studies that were presented today were very well conducted,” she said. “They have very clear results that are very robust.” An Unusual Recommendation Landscape Vaccines are typically formally endorsed by the CDC’s Advisory Committee on Immunization Practices before widespread use and insurance coverage kick in — but that panel has been unable to meet due to an ongoing federal court dispute over its composition and authority. Absent a green light from that committee, the vaccine can still legally be prescribed, but how quickly it gets folded into standard recommendations, and whether insurers move to cover it without that formal endorsement, remains an open question that could shape how widely it’s actually used this fall. The Bigger Picture for mRNA Technology Supporters of the technology argue this approval matters well beyond flu season alone. Because mRNA vaccines can be manufactured and updated far more quickly than traditional egg-based flu vaccines, proponents say the platform gives the country a meaningful head start in responding to fast-mutating flu strains or, in a worst-case scenario, a future pandemic strain — since formulations can be adjusted on a compressed timeline compared to conventional manufacturing. The approval also arrives at a moment when mRNA vaccine technology has faced real skepticism in Washington, with the administration’s broader health leadership having voiced public doubts about the platform in the past. That the FDA ultimately reversed its own initial rejection, following unanimous support from an independent scientific advisory panel, suggests the agency’s career scientific review process held up even amid political headwinds — a point advocates for regulatory independence are likely to highlight going forward. No new or unexpected safety signals emerged during the review; reported side effects, including fatigue, joint pain, and injection-site discomfort, were consistent with what’s typically seen with other mRNA vaccines already on the market. Moderna says it expects mFlusiva to begin reaching select retailers within a few weeks, ahead of the upcoming flu season, with regulatory reviews also underway in the European Union, Canada, and Australia. This story is developing.