In a first, the U.S. has approved a flu 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. The U.S. Health and Human Services (HHS) Secretary 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 initially declined to review Moderna's shot earlier this year, before reversing its decision just a week later.
The vaccine is called mFlusiva and is also made by Moderna. The approval covers two of the most vulnerable populations for flu—adults ages 50 to 65, and adults ages 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 than a standard flu shot in protecting against the disease.
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For more than 70 years, flu vaccines in the U.S. have been manufactured using one of three techniques: egg-based vaccines (these are the most commonly available), cell-culture based vaccines and recombinant vaccines—these vaccines insert harmless genetic material from the 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 whatever three strains of the influenza virus scientists predict may circulate 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 (CDC). The public health agency recommends anyone over the age of six months, who has no health reason preventing it, to get the flu shot 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."
