FDA Reverses Course on Moderna's mRNA Flu Vaccine After Dispute Resolution

Moderna announced that the Food and Drug Administration will consider approving its new mRNA-based flu vaccine for older adults after the two sides resolved a public dispute over the design of the clinical trial. The company said it will seek 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.

Just over a week after the FDA had refused to file the application for Moderna's flu vaccine mRNA-1010, the agency reversed course following a Type A meeting with the biotech. Moderna announced the change on February 18, 2026. The FDA is targeting an approval decision by August 5, 2026.

Moderna's new flu vaccine was found to be more effective in adults age 50 and older compared to a standard flu shot in a 40,000-person clinical trial. The FDA initially refused to review the application, faulting the trial for not including another brand specifically recommended for people 65 and older. Moderna objected, saying the FDA had agreed to the study's design and that the company provided additional comparison data.

The mRNA vaccine demonstrated a 34.5 percent higher relative efficacy at preventing lab-confirmed flu compared to a licensed inactivated vaccine in a large, global Phase 3 trial involving over 18,000 healthy adults aged 18-64. The benefit was primarily on the Influenza A virus, which was able to be studied more closely because it is much more common this year than Influenza B.

In the 2022-2023 flu season, the standard flu shot had an effectiveness of between 44 and 54% for those under 64 years old. Based on the trial results, the new mRNA vaccine would have been 60-67% effective.

The side effects associated with the mRNA vaccine are not unlike those found in the traditional vaccine, including soreness and mild symptoms. Like the flu shot, the mRNA vaccine would contain no live virus, so it would be impossible to catch the actual flu from the vaccine.

The dispute between Moderna and the FDA highlighted the heightened scrutiny that vaccines, particularly those using mRNA technology, have faced under the current administration. The resolution allows Moderna's novel flu shot to potentially reach the market, providing an additional option for older adults who are at higher risk of flu complications. Even if the FDA approves the vaccine, it will still be on the hook for an expensive postmarketing study.