Despite significant drama from Trump officials this year, the Food and Drug Administration has for the first time approved a flu vaccine that uses mRNA technology.
On Thursday, vaccine maker Moderna announced that its flu shot, mRNA-1010, aka mFLUSIVA, had earned approval for use in all adults ages 50 and up. The approval announcement follows a unanimous vote by FDA advisors in June to approve the vaccine. That vote was based on its superior efficacy to existing seasonal flu shots and a good safety record demonstrated in trials that included nearly 44,000 people. After that vote, the FDA set a goal of August 5 for a decision on the vaccine’s fate.
While the unanimous support from FDA advisors boded well for Moderna’s shot, the overall path to approval was treacherous and uncertain, even until the end. For one thing, current Health Secretary Robert F. Kennedy Jr. is a well-established anti-vaccine advocate who has worked diligently in his time in office to thwart vaccinations. One of his first acts as health secretary was canceling a federal campaign to encourage people to get flu shots in the midst of a bad flu season—despite the fact that the Centers for Disease Control and Prevention had already paid for the campaign and the flu season was killing relatively high numbers of children.
Kennedy is also openly hostile to mRNA vaccines, having called the mRNA COVID-19 vaccine the “deadliest vaccine ever made” and canceling hundreds of millions of dollars’ worth of federal research grants for mRNA technology.
In February, Trump appointee Vinay Prasad—a Kennedy ally—refused to even review the vaccine, a move he made despite objections from FDA staff and career officials, shocking Moderna and the larger biomedical community. Prasad defended his decision by arguing that the company didn’t compare its mRNA vaccine’s efficacy to the correct existing vaccine. But Moderna firmly and publicly pushed back, noting that FDA officials previously signed off on its trial designs. The FDA reversed Prasad’s rejection the following week, and Prasad was pushed out of the agency at the end of April amid a series of controversial and widely decried moves.
Remaining uncertainty
At the FDA advisory committee’s June meeting, experts expressed optimism about an mRNA-based flu vaccine. The platform—the same used in the company’s COVID-19 vaccines—is agile, easily allowing tweaks and updates to vaccine design, and it offers swifter vaccine production at scale compared to existing flu vaccines. Traditional flu vaccines are grown in fertilized chicken eggs, a process that requires six to eight months, compared to mRNA vaccines’ one to two months.
Moderna CEO Stéphane Bancel celebrated the approval in a statement Thursday, saying it “demonstrates the continued strength and versatility of our mRNA platform.”
“Flu remains a significant public health challenge, and mFLUSIVA provides an important new option for America’s seniors,” he said. “This approval also reflects the ongoing potential of our mRNA platform to help address important public health challenges through continued scientific innovation.”
Despite the approval, the vaccine still faces some uncertainty. The CDC advisory panel that makes recommendations for federal vaccine policy is effectively defunct. In March, a federal judge ruled that most of the anti-vaccine allies Kennedy had installed onto the advisory panel were unqualified. The judge thus ordered a temporary injunction reversing their appointments and undoing many of Kennedy’s changes to federal vaccine recommendations. The Trump administration is currently appealing the judge’s ruling. But amid the litigation, the CDC’s panel—the Advisory Committee on Immunization Practices—has not met.
Without an ACIP recommendation on mFLUSIVA’s clinical use for the quickly approaching flu season, doctors will face uncertainty about which adults over age 50 should be recommended to use the vaccine. It’s also unclear if mFLUSIVA will be covered by federal vaccine programs or private insurance companies, which are required to cover ACIP-recommended vaccines.
Moderna said it expects to have mFLUSIVA available for the 2026–2027 flu season. But The Wall Street Journal reported that Wall Street is not expecting meaningful sales until the 2027–2028 season.
