There’s a new flu vaccine on the market. Will it move the needle on reducing disease?
Moderna announced on Aug. 5, that the U.S. Food and Drug Administration had approved mFlusiva, the first mRNA-based influenza vaccine
Flu season in the Northern Hemisphere is rapidly approaching and people looking to get their annual shot may now have an additional option.
On Aug. 5, Moderna announced that the U.S. Food and Drug Administration had approved mFlusiva, the first mRNA-based influenza vaccine, for use in all adults 50 years and older. The company expects to have the vaccine available in the U.S. this fall.
Northeastern University public health and pharmacy experts agreed that the new vaccine has the potential to improve vaccine efficiency and efficacy; however, they questioned whether it would significantly change vaccinations in the future.
“I think if you had an epidemic flu, I think it would be a game changer,” said Brandon Dionne, clinical professor of pharmacy and health systems sciences at Northeastern. “Barring that, I think it is more incremental, another tool in the armament.”
While traditional vaccines use a weakened or inactivated form of a pathogen to prompt an immune response that protects against future infections, mRNA vaccines use synthetic mRNA that instructs cells to produce a harmless protein associated with a virus. This alerts the immune system to a foreign agent and provokes an immune response, thereby training the body against future infections, according to Encyclopedia Britannica.
“The challenge with the flu vaccine has always been that the traditional methods required a long lead period,” Dionne said.
That’s because traditional flu vaccines are developed based on what strains of the virus circulated in the prior flu season – generally, October to May in the United States – as well as those circulating in the Southern Hemisphere during its winter (summer in the Northern Hemisphere), according to the U.S. Centers for Disease Control and Prevention (CDC).
That process can take six months, Dionne said, adding, “So you’re always kind of guessing at what the flu strains that are circulating are going to be.”
And sometimes those guesses aren’t very accurate.
The 2025-2026 shot was 36% effective, according to the CDC, meaning it reduced a person’s likelihood of getting sick and needing a doctor visit by 36% compared with someone who did not get the shot. This was down from a 56% effective shot the season before, according to the CDC.
Neil Maniar, director of the master of public health program and professor of practice in public health and health sciences at Northeastern, cited efficiency and efficacy as reasons the mRNA vaccine could address drawbacks of traditional flu vaccines.
“They can be more nimble,” Maniar said. “They can have potentially more precise targeting of the strain that will be more prevalent in the coming season.”
And compared to the six months it takes to develop a traditional vaccine, mRNA vaccines can be developed in about three, Maniar said.
Potentially even more important, Maniar said, was that the Moderna mRNA vaccine has produced a stronger and longer lasting immune response than the standard dose shot.
With the traditional flu vaccine, that immunity starts to wane after a few months,” Maniar said. “So the longer lasting immunity could really make a difference in terms of helping to rein in some of the outbreaks that we typically see.”
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There are still potential complications to the mRNA vaccine being adopted widely.
Vaccine hesitancy, where people delay or outright refuse vaccines, worries Maniar.
He said the familiarity of the flu vaccine and, after the COVID pandemic, mRNA vaccines may make mFlusiva a “seamless transition” for people who regularly vaccinate, but “misinformation and disinformation” about COVID mRNA vaccine may lead to hesitancy and delay people from taking the mRNA flu vaccine.
For instance, according to a 2023 survey by the Pew Research Center, 21% of American adults — or roughly 1 in 5 — reject flu and COVID vaccines altogether.
“There’s a lot of work that we need to do to kind of rebuild that infrastructure around education related to vaccinations,” Maniar said.
After mFlusiva’s approval, a spokesman for HHS told reporters at NBC and other outlets that “Secretary [Robert F. Kennedy Jr.] has been clear that he believes mRNA products warrant heightened scientific scrutiny. That’s why this vaccine is entering the market with some of the strongest post-market study commitments FDA has required, particularly for individuals 65 years of age and older.”
Other complications to rolling out the vaccine widely are more mundane.
Most hospitals and health care providers order large quantities of the standard dose, and the vaccine is only approved for those 50 years and older.
“A lot of uptake is going to be based on what’s available more than clear patient choice,” Dionne said. “If you wanted a specific type [of vaccine], you might have to go a long distance to find someone that actually has it because most people are just stocking the most common vaccines.”
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