FDA approves Moderna's mRNA flu vaccine after initial pushback

The U.S. Food and Drug Administration has approved a new seasonal flu vaccine from Moderna that uses mRNA technology, the drugmaker announced Wednesday.

mFLUSIVA, approved for adults ages 50 and older, is the first influenza vaccine using mRNA technology to receive FDA approval.

"This approval also reflects the ongoing potential of our mRNA platform to help address important public health challenges through continued scientific innovation," Moderna said in a statement. "We are grateful to the clinical trial participants, investigators, regulators and Moderna teams whose contributions made this milestone possible."

The FDA is part of the U.S. Department of Health and Human Services, and the approval comes despite repeated criticism of mRNA technology by Health and Human Services Secretary Robert F. Kennedy Jr. Last year, Kennedy canceled 22 vaccine development projects that use mRNA technology.

The FDA had earlier this year said it would refuse to consider Moderna' application. But it reversed course about a week later and stated it would allow the vaccine to proceed to review after discussions with Moderna "led to a revised regulatory approach and an amended application, which FDA accepted."

The dispute had centered on a 40,000-person clinical trial that found Moderna's new vaccine was more effective in adults aged 50 and older than one of the standard flu shots used today. In a refusal-to-file letter sent to Moderna though, FDA vaccine director Dr. Vinay Prasad faulted the trial for not including another brand specifically recommended for people 65 and older.

Moderna subsequently revised its application to seek full vaccine approval for adults aged 50 to 64 and accelerated approval for adults aged 65 and older. The drugmaker also agreed to conduct an additional study of the drug's use by older adults.

Moderna said it expects to have mFLUSIVA available for the 2026-27 flu season.