Federal health advisers have recommended approval for the first mRNA-based influenza vaccine, a move that could shift how the U.S. addresses seasonal flu. The Food and Drug Administration (FDA) is currently evaluating Moderna’s “mFlusiva” for adults ages 50 and older. If authorized, this vaccine would leverage the same messenger RNA technology used in COVID-19 shots to potentially provide faster manufacturing and better matching against mutating flu strains, according to the FDA advisory committee.
How does mRNA technology improve flu vaccines?
Traditional flu vaccines are often manufactured using egg-based methods, which can take months to produce and may result in a mismatch if the virus mutates during that time. Moderna’s mRNA approach allows for a faster production cycle, potentially enabling the company to update vaccine recipes closer to the start of the flu season. According to Dr. Flor Munoz-Rivas of Texas Children’s Hospital, this technology positions the healthcare system to better prepare for emerging strains. Moderna’s Dr. Rituparna Das noted that a closer match between the vaccine and circulating virus could significantly reduce hospitalizations among older populations.
What were the results of the clinical trials?
In a study involving 40,000 participants aged 50 and older, Moderna reported that its mRNA vaccine reduced flu cases by approximately 27% when compared to a standard-dose vaccine, according to company data presented to the FDA. For the 65-and-older cohort, Moderna’s shot demonstrated a strong protective immune response comparable to high-dose vaccines already on the market. FDA adviser Dr. Anna Durbin of Johns Hopkins University described these immune reaction data as “very compelling.”
Are there side effects to the new vaccine?
Clinical data showed no major safety concerns, though participants did report temporary reactions similar to those observed with COVID-19 mRNA vaccines. These include injection-site pain, headache, fever, fatigue, and muscle aches. Dr. Hayley Gans of Stanford Medicine emphasized that these symptoms are common and serve as a signal that the immune system is actively responding to the vaccine. The FDA noted that these side effects occur somewhat more frequently with mRNA technology than with traditional, non-mRNA flu shots.
What is the current status of the FDA approval process?
The FDA is expected to reach a final decision by early August. The process faced an unusual public dispute earlier this year when a former FDA vaccine official blocked the application, arguing that the vaccine should have been compared to a high-dose senior-specific shot rather than a standard-dose brand. Following a challenge from Moderna, which cited a smaller study comparing its shot to high-dose alternatives, the FDA accepted the application. FDA reviewer Dr. Timothy Brennan indicated at the advisory meeting that the agency is open to approval for older adults, even as further studies on frail seniors remain a priority.
Frequently Asked Questions
- Is the mRNA flu vaccine currently available? No. It is currently under review by the FDA, with a final decision expected by early August.
- How does this compare to current flu shots? It uses mRNA technology for potentially faster manufacturing and, in studies, showed a 27% reduction in flu cases compared to standard-dose vaccines.
- Who is the target audience for this vaccine? Moderna is seeking approval for adults ages 50 to 64, with plans for additional testing in those 65 and older.
- Are the side effects worse than regular flu shots? Side effects like fever and arm pain are common and occurred slightly more often in trials than with traditional flu shots, according to FDA reports.
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