In a first, the U.S. has approved an influenza vaccine that relies on mRNA technology—the same technology that underpinned the wildly successful Pfizer-BioNTech and Moderna COVID vaccines.
The approval marks a sea change for the Trump administration. Secretary of Health and Human Services Robert F. Kennedy, Jr., is a vocal critic of mRNA vaccines. And his agency has canceled millions of dollars in funding for mRNA vaccine research. Indeed, the Food and Drug Administration, which falls under Kennedy’s Department of Health and Human Services, initially declined to review the mRNA flu shot earlier this year before reversing its decision just a week later.
That vaccine is called mFlusiva and is made by Moderna. The approval covers two of the most vulnerable populations for flu—adults aged 50 to 65 and adults aged 65 and up—on the condition that Moderna will run a further clinical trial in the older group. Past trial data show that Moderna’s vaccine is around 27 percent more effective at protecting against the disease than a standard flu shot.
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For more than 70 years, flu vaccines in the U.S. have been manufactured using one of three techniques: there have been egg-based vaccines (the most commonly available type), cell-culture based vaccines and recombinant vaccines. Vaccines in the last category insert harmless genetic material from a virus into cells in order to trigger the immune system.
Messenger RNA, or mRNA, vaccines work differently. Messenger RNA copies instructions from viral DNA and teaches the body’s cells to build and recognize copies of viral proteins. The body can then create antibodies if it should ever encounter that protein again, enabling it to fight off infections.
The other great advantage of mRNA vaccines is that they can be rejiggered quickly to respond to emerging strains of a virus. Traditional flu vaccines are made to protect people from the types of influenza viruses that scientists predict may circulate in people during the forthcoming flu season. But they have to be made six months in advance of the actual flu season, which means these predictions can fall short of reality. Moderna’s new vaccine takes just two to three months to manufacture and roll out.
The flu kills between 6,300 and 52,000 people each year, according to the Centers of Disease Control and Prevention. The public health agency recommends anyone older than the age of six months who has no health reason preventing them from getting a flu shot to receive one every year in order to protect against disease.
“The Food and Drug Administration’s approval of a new mRNA flu vaccine is welcome news and provides another important option to help protect people from a virus that sends hundreds of thousands of Americans to the hospital each year and claims thousands of lives," said Ronald G. Nahass, president of the Infectious Disease Society of America, in a statement. “As we prepare for flu season, the most important message is simple: Vaccination saves lives.”