The FDA in February slapped Moderna’s vaccine with a refusal-to-file letter—though the agency backtracked a few days later and accepted a revised submission for review. An advisory committee in June unanimously backed mFLUVISA’s approval.
From an outright refusal to file to a backpedaled review earlier this year, Moderna has secured the FDA’s greenlight for its mRNA-based flu vaccine mFLUVISA.
The decision, revealed late on Wednesday, grants traditional approval for mFLUVISA to prevent seasonal influenza in patients 50 through 64 years of age, and accelerated approval for use in people 65 years and older. MFLUVISA is the first mRNA-based flu shot in the U.S., according to Moderna’s announcement.
The company expects to make mFLUVISA available “in the coming weeks,” in time for the 2026-2027 respiratory virus season in the U.S. Moderna didn’t disclose pricing for mFLUVISA.
The approval “adds another commercial growth driver for 2027-28” beyond Moderna’s largely COVID-reliant revenues, Jefferies told investors in a Wednesday evening note. Indeed, while the shot will be available this year, analysts expect mFLUVISA sales to “likely skew toward 2027” since flu is largely contracted from January through March.
More broadly, the approval is a vindication for mFLUVISA, which in February was hit with a refusal-to-file letter—meaning the FDA would not accept the submission for review. The letter was signed by Vinay Prasad, former director of the Center for Biologics Evaluation and Research (CBER), who claimed that Moderna’s pivotal study did not qualify as an “adequate and well-controlled trial.”
In particular, Prasad said that Moderna’s control group “does not reflect the best-available standard of care.” The company disputed this characterization, contending that the FDA’s own guidance for vaccine developers doesn’t reference the requirement for such controls—and noting that the agency had previously signed off on Moderna’s Phase 3 plans.
Ultimately, after days of strong criticism from the industry, the FDA accepted a revised application for mFLUVISA. At the end of April, Prasad exited the agency, followed soon after by former Commissioner Marty Makary, an avid defender of Prasad. CBER is now temporarily headed by Karim Mikhail.
In June, mFLUVISA faced the FDA’s Vaccines and Related Biological Products Advisory Committee, which voted unanimously in favor of the vaccine’s approval.
Moderna backed its flu shot with a broad late-stage program. One study, results from which were released in June 2025, showed that mFLUVISA was 26.6% more effective than a commercial standard-dose flu vaccine at preventing influenza in adults 50 years and older.
The company is running a post-marketing trial of the vaccine to confirm its clinical benefit in adults 65 years and older, according to the Wednesday release.
