FDA grants first U.S. approval for Moderna's mRNA flu vaccine
The FDA approved Moderna's mFlusiva for adults 50 and older, citing a late-stage trial that showed about 27% higher efficacy than standard flu shots, with the company required to conduct further studies in the oldest age group.
The U.S. Food and Drug Administration approved Moderna's mRNA-based influenza vaccine, mFlusiva, for adults aged 50 to 65 and for those 65 and older, with the condition that an additional clinical trial be completed for the latter group. In a late-stage study involving more than 40,000 participants across 11 countries, the vaccine demonstrated roughly 27% greater effectiveness than a conventional flu shot, though side effects such as injection-site pain, fatigue and headache were reported more frequently, albeit mild to moderate.
Proponents note that mRNA technology can shorten the production timeline from six months for traditional vaccines to two or three months, potentially allowing a better match to circulating influenza strains. Dr. Ofer Levy, director of the Precision Vaccines Program at Boston Children’s Hospital, said the faster turnaround could improve the precision of strain selection.
The advisory committee of the FDA voted unanimously in June to recommend approval. The agency had initially delayed review, requesting more data because the trial compared mFlusiva with a standard flu shot rather than the high-dose vaccine typically advised for seniors. The FDA later reversed its position and granted approval.
Moderna plans to make mFlusiva available for the upcoming flu season. However, the vaccine has not yet received formal recommendation from the CDC’s Advisory Committee on Immunization Practices, and a federal judge has blocked that committee from meeting. Without such endorsement, private insurers may limit coverage, and public programs that rely on CDC guidance could face distribution challenges.