Despite a major curveball thrown by the FDA earlier this year, Moderna has managed to strike true with a U.S. approval for its mRNA-based influenza vaccine.
The FDA on late Wednesday signed off on Moderna’s vaccine, christened mFlusiva, to prevent seasonal influenza in all adults ages 50 years and older. With the green light, Moderna has scooped up its fourth FDA nod and cleared the way for the first-ever flu shot leveraging mRNA technology in the United States.
The vaccine’s odds of approval stateside were thrown into flux in February when the FDA issued Moderna a rare refusal to file (RTF) letter, citing concerns with the design of the phase 3 trial for the shot, at the time known as mRNA-1010.
Moderna publicly pushed back against the FDA’s decision not to take up its application, and the agency—whose Center for Biologics Evaluation and Research (CBER) responsible for vaccines was at the time headed up by controversial director Vinay Prasad, M.D.—reversed course a little over a week later.
The FDA’s concerns specifically came down to the use of a standard-dose flu vaccine as the comparator arm in one of the trial’s supporting mFlusiva’s approval. The FDA at the time suggested that it had issues because Moderna had not used “the best-available standard of care” in its study—a position the company disagreed with and noted that the FDA had not flagged as a problem when previously discussing trial protocols.
At one additional checkpoint on the way to approval, the FDA’s Vaccines and Related Biological Products Advisory Committee voted unanimously that mFlusiva’s benefits outweighed its risks across both the 50-to-64-year age group and in patients ages 65 years and older.
With regards to those age groups, mFlusiva has secured a traditional FDA approval in the 50-to-64-year bracket and an accelerated nod in the older group. The decision was backed up by data from a pair of phase 3 trials, with the study in the younger patient group comparing mFlusiva’s relative vaccine efficacy, among other measures, against a standard-dose comparator shot. The study in adults ages 65 and up pitted mFlusiva against a high-dose inactivated flu shot but with immunogenicity as the primary objective.
As required by an accelerated approval, Moderna noted that it will run a postmarketing trial to confirm its vaccine’s benefit in the older patient population.
With the colder months drawing nearer, Moderna says it expects to make mFlusiva available in the U.S. for the 2026-2027 respiratory virus season. The new vaccine will join the stable of Moderna’s other mRNA vaccines Spikevax and mNexspike for COVID-19, and mResvia in respiratory syncytial virus.
"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," Moderna helmsman Stéphane Bancel said in a Wednesday statement.
"Flu remains a significant public health challenge, and mFlusiva provides an important new option for America's seniors,” he continued. “This approval also reflects the ongoing potential of our mRNA platform to help address important public health challenges through continued scientific innovation.”
Outside the U.S., Moderna’s mFlusiva application has been taken under review in the European Union, Canada and Australia.
While the solo flu shot is awaiting a verdict in Europe, the EMA’s Committee for Medicinal Products for Human Use (CHMP) recommended approval for Moderna’s mCombriax in patients ages 50 and up. That mRNA vaccine is designed to confer protection against COVID and flu in a single combo shot.