The FDA has approved Moderna’s mFLUSIVA, the first mRNA-based influenza vaccine, for adults ages 50 years and older, opening a new option for flu prevention ahead of the 2026 to 2027 respiratory virus season. The shot uses the same underlying technology as the mRNA COVID-19 vaccine, and Moderna expects it to be available in the United States for that season.
Dung Trinh called the approval an important addition to influenza prevention for adults over 50, and he described it as a significant scientific milestone because it brings mRNA technology into seasonal flu protection. That matters now because the approval lands as flu remains a major cause of illness and death: there were an estimated 45,000 flu-related deaths in the United States in the 2024 to 2025 flu season, and vaccination was estimated to have prevented around 12,000 of them.
The FDA’s decision rested on a phase 3 clinical trial that followed more than 40,000 adults ages 50 and older across 11 countries. About half received mFLUSIVA and the rest got a standard-dose licensed flu vaccine. Researchers concluded that Moderna’s shot was superior at preventing flu-like illness confirmed by RT-PCR lab tests. For adults ages 50 to 64, the agency granted traditional full approval. For adults ages 65 and older, it took a different route: accelerated approval, based on a separate study of over 2,900 adults in the United States that looked at immune response against a high-dose inactivated flu shot.
That split matters because the older group is the one in which the biggest unanswered question remains whether the vaccine actually prevents hospitalization, pneumonia and death. David Cutler said the approval is scientifically interesting and potentially important, but he would not treat it as proof that the mRNA vaccine is the best flu vaccine for everyone over 50. In practice, the approval gives Moderna a regulatory foothold, but it also leaves the company with a higher bar to clear before the oldest adults can be treated as fully settled evidence-based territory.
Flu viruses keep changing, and that is one reason vaccine performance can vary from season to season. Moderna’s mFLUSIVA is entering a crowded field of prevention tools, but it is also the first of its kind to clear the FDA for seasonal influenza. The next milestone is not approval itself. It is whether Moderna can deliver the post-approval evidence needed to show that the vaccine does more than raise immune markers in adults 65 and older, and whether it reaches U.S. pharmacies in time for the 2026 to 2027 respiratory virus season.
