The Food and Drug Administration modernaThe company’s announcement Tuesday of its application for an experimental flu shot is another sign of the Trump administration’s influence on tightening U.S. vaccine regulations.
The company’s shares fell about 7% in after-hours trading Tuesday.
Moderna said the move contradicts previous feedback from regulators even before it filed an application and began Phase 3 trials of the shot, called mRNA-1010. The drugmaker said it had requested a meeting with the FDA to “understand the path forward.”
Moderna noted that the agency did not identify specific issues with the vaccine’s safety or effectiveness but objected to the study plan, even though it had previously approved it. The company added that this action will not impact its financial outlook for 2026.
Moderna’s jab showed positive data in phase 3 last year and met all trial targets. Moderna said at the time that the single flu shot is key in its efforts to develop a combination vaccine that targets both influenza and the new coronavirus.
The announcement follows major changes to U.S. vaccination policy over the past year under Secretary of Health and Human Services Robert F. Kennedy Jr., a prominent vaccine skeptic.
Moderna on Tuesday specifically singled out Vinay Prasad, who returned to head the FDA’s vaccine regulator in August after being ousted. Prasad, director of the agency’s Center for Biologics Evaluation and Research (CBER), has been a vocal advocate for tighter regulation of vaccines, recently linking a child’s death to COVID-19 vaccination.
In a letter he signed on Feb. 3, Prasad said the only reason the FDA refused to review the application was because of how clinical trials on the shot were designed.
The agency specifically took issue with Moderna’s decision to compare its product to the standard, approved influenza shot, arguing that it “does not reflect the best available standard of care.” As a result, the FDA said the study did not meet the definition of an “adequate and well-controlled” trial.
Moderna disputed this reasoning, pointing out that FDA rules and guidance do not actually require trials to use the most advanced or highest-dose vaccines as comparators in clinical studies.
“CBER’s decision, which found no concerns about the safety or efficacy of our products, does not advance our shared goal of advancing America’s leadership in the development of innovative medicines,” Moderna CEO Stéphane Bancel said in a release. “Comprehensive review of influenza vaccine applications using FDA-approved vaccines as comparators in studies that have been discussed and agreed upon with CBER prior to initiation should not be controversial.”
Moderna said it expects the earliest approval of its flu shot to be in late 2026 or 2027, pending regulatory review in the U.S., Europe, Canada and Australia.
The FDA said it does not comment on regulatory communications to individual sponsors.
