The U.S. Food and Drug Administration has declined to review Moderna’s submission for a new influenza vaccine utilizing Nobel Prize-winning mRNA technology, as disclosed by the company on Tuesday. This development reflects the FDA’s increased scrutiny of vaccines during Health Secretary Robert F. Kennedy Jr.’s tenure, particularly those employing mRNA technology, which he has been critical of both before and after assuming the role of the nation’s top health official.
Moderna received a “refusal-to-file” communication from the FDA, objecting to the methodology employed in a 40,000-person clinical trial that compared its novel vaccine to a standard flu shot currently in use. The trial indicated that the new vaccine demonstrated slightly higher effectiveness in individuals aged 50 and above compared to the standard shot. The FDA’s vaccine director, Dr. Vinay Prasad, stated in the letter that the application lacked an “adequate and well-controlled trial” because it did not compare the new vaccine to the “best-available standard of care in the United States at the time of the study.” Prasad referenced guidance given to Moderna in 2024 under the Biden administration, which the company did not adhere to.
Moderna stated that the feedback allowed the use of the selected standard-dose flu shot but recommended a different brand specifically for seniors aged 65 and above in the study. However, Moderna asserted that the FDA approved the study to proceed as initially planned. The company also shared additional data from a separate trial comparing the new vaccine to a licensed high-dose shot used for seniors.
Moderna’s CEO, Stephane Bancel, mentioned that the FDA did not raise any safety or efficacy concerns regarding their product. The company is seeking an urgent meeting with the FDA and has submitted the vaccine for approval in Europe, Canada, and Australia.
Under Kennedy’s leadership, there have been changes in recommendations surrounding COVID-19 vaccines, including the addition of extra warnings to the leading mRNA-based COVID vaccines, as well as the exclusion of critics from an FDA advisory panel. Last year, Kennedy announced the cancellation of over $500 million in funding for the development of mRNA-based vaccines.
The FDA has historically allowed vaccine manufacturers to swiftly update their annual flu vaccines to target the latest strains by demonstrating an immune response in patients, a more efficient approach compared to prolonged studies tracking flu occurrence and outcomes in patients. An internal memo by Prasad last year indicated a shift away from this streamlined method, prompting criticism from numerous former FDA commissioners.