The Food and Drug Administration is refusing to consider Moderna’s application for a new flu vaccine made with Nobel Prize-winning mRNA technology, the company announced Tuesday.
The news is the latest sign of the FDA’s heightened scrutiny of vaccines under Health and Human Services Secretary Robert F. Kennedy Jr., particularly those using mRNA technology, which he has criticized before and after becoming the nation’s top health official.
Moderna says it received what is called a “refusal-to-file” letter from the FDA that objected to how it conducted a 40,000-person clinical trial comparing its new vaccine to one of the standard flu shots used today. That trial concluded the new vaccine was somewhat more effective in adults 50 and older than that standard shot.
The letter from FDA vaccine director Dr. Vinay Prasad said the agency doesn’t consider the application to contain an “adequate and well-controlled trial” because it didn’t compare the new shot to “the best-available standard of care in the United States at the time of the study.” Prasad’s letter — which Moderna published online — pointed to some advice that FDA officials gave Moderna in 2024, under the Biden administration, which Moderna didn’t follow.
According to Moderna, that feedback said it was acceptable to use the standard-dose flu shot the company had chosen — but that another brand specifically recommended for seniors would be preferred for anyone 65 and older in the study. Still, Moderna said, the FDA did agree to let the study proceed as originally planned.
The company said it also had shared with the FDA additional data from a separate trial comparing the new vaccine against a licensed high-dose shot used for seniors.
The FDA “did not identify any safety or efficacy concerns with our product” and “does not further our shared goal of enhancing America’s leadership in developing innovative medicines,” Moderna CEO Stephane Bancel said in a statement.
CBS News has reached out to the FDA for comment.
It’s rare for FDA to refuse to file an application, particularly for a new vaccine, which requires companies and FDA staff to engage in months or years of discussions.
Moderna has requested an urgent meeting with the FDA, and noted that it has applied for the vaccine’s approval in Europe, Canada and Australia.
In the last year, FDA officials working under Kennedy have rolled back recommendations around COVID-19 shots, added extra warnings to the two leading COVID vaccines — which are made with mRNA technology — and removed critics of the administration’s approach from an FDA advisory panel.
Kennedy announced last year that his department would cancel more than $500 million in contracts and funding for the development of vaccines using mRNA, zeroing in on research into coronavirus and flu vaccines.
Kennedy said the Department of Health and Human Services had determined that “mRNA technology poses more risk than benefits for these respiratory viruses.” Vaccine experts condemned the decision, with Jerome Adams, who served as surgeon general in President Trump’s first term, writing on social media, “quite frankly this move is going to cost lives.”
The FDA for decades has allowed vaccine makers to quickly update their annual flu shots to target the latest strains by showing that they trigger an immune response in patients. That’s a far more efficient approach than running long-term studies tracking whether patients get the flu and how they fare.
In an internal memo last year, Prasad wrote that the streamlined method would no longer be permitted – leading more than a dozen former FDA commissioners to pen an editorial condemning the statements.
Democratic Sen. Patty Murray of Washington condemned the FDA’s decision on Moderna, saying Kennedy’s team was “blocking an updated flu vaccine for no reason grounded in science.”
“American vaccine policy has been hijacked by a conspiracy theorist—yet most Republicans are happy to just sit on their hands,” Murray wrote on X.
