Moderna Inc has asked for a meeting with the US Food and Drug Administration to query the agency’s decision to refuse to review its candidate mRNA vaccine for influenza. Effective 16 February, the agency hadn’t disclosed whether or not it would consider a follow-up discussion known as a Type-A meeting. This follows an event in early February when the director of the FDA’s biologics evaluation and research division at the agency, Vinayak Prasad, issued a refusal-to-file letter to Moderna overruling the advice of career staff at the agency. In the letter, issued on 3 February, Dr Prasad wrote that the control arm of the clinical data supporting the application did not reflect the best-available standard of care and therefore the application could not be progressed. The comparator in the study was a standard dose of an approved vaccine. Dr Prasad wrote that the comparator should have been a high-dose vaccine suitable for people 65 years and older. According to Moderna, the protocol for the trial, including the comparator, had been discussed and approved by the agency prior to the start of the Phase 3 trial. Safety and efficacy results of the trial, reported in August 2025, were positive.
Under FDA rules, a company can ask for a meeting to discuss a refusal to file letter within 30 days of the letter’s receipt.
Separately, Stéphane Bancel, the Moderna chief executive, told STAT news in an interview on 12 February that there were strong economic and healthcare incentive to use mRNA for influenza vaccines rather than conventional technologies0. Under conventional methods, companies have to select influenza strains for a vaccine as early as February every year. mRNA technology makes it possible to make these selections later and still have the products ready ahead of the influenza season.
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