Moderna says the FDA refuses to review its flu vaccine application

The Food and Drug Administration declined to initiate a review ModernaThe company on Tuesday announced an order for its experimental flu vaccine, in another sign of the Trump administration’s influence in tightening vaccine regulations in the United States.

Moderna said the move conflicts with previous comments the agency made before submitting the application and beginning phase 3 trials of the dose, called mRNA-1010. The drugmaker said it has requested a meeting with the FDA to “understand the path forward.”

Moderna noted that the agency did not identify any specific safety or efficacy issues with the vaccine, but instead objected to the study design, despite having previously approved it. The company added that this move will not affect its financial guidance for 2026.

The Moderna vaccine showed positive Phase 3 data last year, meeting all of the trial’s goals. At the time, Moderna said the standalone influenza vaccine was key to its efforts to develop a combination vaccine targeting both influenza and COVID-19.

The announcement follows sweeping changes in US immunization policy over the past year under Health and Human Services Secretary Robert F. Kennedy Jr., a prominent vaccine skeptic.

Moderna on Tuesday specifically pointed to Vinay Prasad, the FDA’s top vaccine regulator, who returned to the agency in August after being ousted. Prasad, who heads the agency’s Center for Biological Evaluation and Research, or CBER, has been vocal about tightening regulations on vaccines and recently linked childhood deaths to Covid shots.

In a letter signed by Prasad on February 3, he said the only reason the FDA declined to review the application was because of how the clinical trial for the shot was designed.

The agency specifically took issue with Moderna’s decision to compare its product to the standard approved influenza vaccine, arguing that it “does not reflect the best standards of care available.” As a result, the FDA said the study did not meet its definition of an “adequate and well-controlled” trial.

Moderna disputes that reasoning, noting that FDA rules and guidance do not actually require trials to use the most advanced or highest-dose vaccine as a comparator in clinical studies.

“This decision by CBER, which did not identify any safety or efficacy concerns regarding our product, does not advance our shared goal of strengthening America’s leadership in developing innovative medicines,” Moderna CEO Stephane Bancel said in a statement. “It should not be controversial to conduct a comprehensive review of influenza vaccine delivery that uses an FDA-approved vaccine as a comparator in a study that has been discussed and agreed upon with CBER before initiation.”

Moderna said it expects the earliest approval for its flu vaccine will be in late 2026 or late 2027, pending regulatory reviews in the United States, Europe, Canada and Australia.

The FDA said it does not comment on regulatory communications with individual sponsors.