The U.S. Food and Drug Administration (FDA) has approved Moderna's new flu vaccine, the first to utilize mRNA technology, manufacturer Moderna announced Thursday. The vaccine is approved for adults aged 50 to 64 and has received accelerated approval for individuals 65 and older, pending further study to confirm its efficacy in this age group.
This new vaccine is built on the same messenger RNA platform used in successful COVID-19 vaccines. Experts suggest that mRNA vaccines can be more rapidly updated to adapt to changes in circulating influenza strains each year. During a Phase 3 clinical trial involving approximately 40,000 participants, the mRNA vaccine showed a 27% reduction in flu cases compared to a standard flu vaccine.
The trial did not identify any major safety concerns. However, the vaccine was associated with more short-term side effects than conventional flu shots, including mild and temporary arm pain, fatigue, headache, and fever.
"It’s not a universal vaccine, but is geared for rapid turnaround once the yearly strains have been identified," said Dr. Marc Siegel, Fox News senior medical analyst. He added that the vaccine is "geared to protect the elderly" and was found to be 25% to 30% more effective than current flu vaccines.
Older adults are at the highest risk for severe influenza. In the 2024-2025 flu season, individuals aged 65 and older accounted for 57% of flu-related hospitalizations and 71% of deaths, according to the Centers for Disease Control and Prevention. An estimated 51 million Americans contracted the flu in the 2024-2025 season, resulting in approximately 710,000 hospitalizations and 45,000 deaths.
The path to this approval included an initial setback earlier in the year when the FDA initially declined to review Moderna's application due to concerns about the clinical trial design. Moderna disputed this decision, and the FDA subsequently agreed to proceed with the review. In June, an independent FDA advisory committee supported the vaccine, concluding that its benefits outweighed its risks, which paved the way for final approval.
Moderna is also exploring the development of combination vaccines that could protect against multiple respiratory viruses simultaneously, potentially leading to a single seasonal shot for flu and COVID-19.