The U.S. Food and Drug Administration has declined Moderna’s request for a novel flu vaccine developed using mRNA technology, the company disclosed on Tuesday. This decision reflects the FDA’s increased scrutiny of vaccines during Secretary of Health Robert F. Kennedy Jr.’s tenure, especially those utilizing mRNA technology, which he has criticized in the past and present.
Moderna was issued a “refusal-to-file” notice by the FDA, citing concerns about the methodology of a 40,000-person clinical trial comparing their new vaccine with a standard flu shot currently in use. The trial indicated that the new vaccine showed slightly better efficacy in adults aged 50 and above compared to the standard shot.
FDA’s vaccine director, Dr. Vinay Prasad, stated in the letter that the FDA deemed the application lacking an “adequate and well-controlled trial” as it did not compare the new vaccine with the best-available standard of care at the time of the study. Moderna had received advice from FDA officials in 2024, during the Biden administration, which the company did not fully adhere to.
Despite this setback, Moderna proceeded with the study as planned after the FDA agreed to it. The company informed the FDA about additional data from a separate trial comparing the new vaccine with a licensed high-dose shot for seniors, and the FDA did not raise any safety or efficacy concerns about the product, according to Moderna CEO Stephane Bancel.
Rarely does the FDA decline to file an application, especially for a new vaccine, as it involves extensive discussions between companies and FDA personnel over months or years. Moderna has requested an urgent meeting with the FDA and has also sought approval for the vaccine in Europe, Canada, and Australia.
Under Kennedy’s leadership, there have been changes in recommendations concerning COVID-19 vaccines, including the addition of extra warnings to the two leading COVID vaccines, both of which use mRNA technology. Critics of the administration’s approach have also been removed from an FDA advisory panel.
Last year, Kennedy announced the cancellation of over $500 million in contracts and funding for the development of mRNA-based vaccines. The FDA has traditionally allowed vaccine manufacturers to swiftly update their annual flu shots to target the latest strains by demonstrating an immune response in patients, a more efficient process than conducting long-term studies tracking flu incidence and outcomes.
In a memo last year, Prasad indicated that the streamlined approach would no longer be permitted, prompting criticism from more than a dozen former FDA commissioners who penned an editorial condemning the decision.
