Moderna has secured a landmark FDA approval for mFlusiva, its mRNA-based influenza vaccine, marking the first time mRNA technology has been cleared for flu prevention in the United States.
The approval covers adults aged 50 and older and represents Moderna’s fourth FDA-approved product, adding to the company’s growing portfolio of mRNA-based medicines.
mFlusiva received a traditional FDA approval for adults aged 50 to 64, while adults aged 65 and older received approval under the agency’s accelerated pathway, reflecting differences in trial design across those two age groups.
As a condition of the accelerated approval for older adults, Moderna is required to conduct a postmarketing trial to confirm the vaccine’s clinical benefit in that population.
The path to approval was far from straightforward, following a rare refusal-to-file letter issued by the FDA in February that temporarily threw the application into serious doubt.
Vinay Prasad, who was then serving as the FDA’s head of biologics, overturned recommendations from career staff and issued the refusal, stating the agency would not review the available data package.
Prasad’s objection centred on Moderna’s failure to use an adjuvanted or high-dose vaccine as a comparator in the older age group, a concern the FDA had reportedly raised with the company before the trial began.
Moderna publicly disclosed the FDA’s decision and expressed its displeasure, and within a week Prasad reversed course and the agency agreed to review the application. Prasad left the FDA at the end of April.
The approval was supported by data from two phase 3 trials, one enrolling 40,805 adults aged 50 and above and a separate study involving 2,992 adults aged 65 and older.
In a late-stage trial, mFlusiva was found to be approximately 27% more effective than a standard-dose flu shot, providing a meaningful efficacy advantage for older Americans seeking seasonal protection.
The approval also had backing from the FDA’s Vaccines and Related Biological Products Advisory Committee, which issued unanimous recommendations supporting mFlusiva for adults aged 50 and older.
One of the most significant advantages of mRNA flu vaccine technology is manufacturing speed, with Moderna stating its process takes two to three months from strain selection to rollout, compared with around six months for traditional flu shots.
Experts have suggested that a licensed mRNA seasonal flu vaccine could also accelerate the approval pathway for a pandemic flu vaccine, should the need arise in future.
Stéphane Bancel, Chief Executive Officer of Moderna, said: “The FDA approval of mFLUSIVA, our fourth approved product in the United States and the first mRNA-based flu vaccine, demonstrates the continued strength and versatility of our mRNA platform.”
Bancel added: “Flu remains a significant public health challenge, and mFLUSIVA provides an important new option for America’s seniors. This approval also reflects the ongoing potential of our mRNA platform to help address important public health challenges through continued scientific innovation.”