FDA approves first mRNA-based flu vaccine

The FDA has approved Moderna’s mRNA-based flu vaccine, the first new vaccine against seasonal flu. mFlusiva was approved for use in all adults 50 years and older and indicated for the prevention of influenza virus subtypes A and type B.

Seasonal influenza remains a significant public health burden, according to the CDC. Older adults account for a disproportionate share of severe influenza outcomes, including hospitalizations and deaths. According to the CDC, seasonal flu-related hospitalizations and outpatient visits reached a 15-year high during the 2024-2025 season. More than 600,000 Americans were hospitalized due to flu-related illness last year.

“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,” Stéphane Bancel, CEO of Moderna, said in a news release.

mFlusiva is developed using Moderna’s mRNA platform, the technology it used to develop a vaccine for COVID-19. mRNA vaccines work by introducing a piece of messenger RNA that corresponds to a viral protein, which the immune system is then able to recognize and produce antibodies against.

The approval for use of mFlusiva in people 50 to 64 years of age is based on n results from a phase 3 clinical trial that enrolled 40,805 adults aged 50 years and older across 11 countries. The primary objectives in this study were to evaluate the safety and reactogenicity of mFlusiva and to evaluate relative vaccine efficacy (rVE) compared with a standard dose (SD) active comparator.

The FDA granted accelerated approval of mFlusiva in adults 65 years of age and older based on results from an active-controlled clinical trial, which enrolled 2,992 adults in the United States. The primary objective in this study was to evaluate the immunogenicity of mFlusiva compared with a high-dose (HD) inactivated influenza vaccine comparator.

In the phase 3 trial, most adverse reactions were mild to moderate. Adverse reactions were more frequent with mFlusiva than with the standard-dose comparator and included injection-site pain, fatigue, headache and myalgia. Serious adverse events were reported in 2.2% of the recipients of mRNA-1010 (with three events considered by the investigator to be vaccine-related) and in 1.9% of the recipients of the standard-dose comparator (with two events considered by the investigator to be vaccine-related)

In June 2026, the FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC), voted 9-0 in of the vaccine, saying the benefits outweigh its risks for the prevention of influenza in both age groups. The committee considered the results of the phase 3 program, The discussion included data from Moderna's phase 3 clinical program, which was published in May 2026 in The New England Journal of Medicine.

Moderna’s flu vaccine has been accepted for regulatory review in the European Union, Canada and Australia. Regulatory submissions in additional countries are planned during 2026.

Moderna expects mFlusiva to be available in the United States for the 2026-2027 respiratory virus season, alongside Spikevax (COVID-19 vaccine), mRESVIA (respiratory syncytial virus vaccine) and mNEXSPIKE (COVID-19 vaccine).