The Food and Drug Administration has declined to review Moderna’s application for their experimental flu shot, causing the company’s stock to drop by 7% in after-hours trading. Despite no safety or efficacy issues identified, the FDA objected to the study design, impacting Moderna’s 2026 financial guidance.

Moderna’s jab, mRNA-1010, showed positive phase three data last year, meeting all trial goals. This development is crucial for the company’s efforts to create a combination vaccine targeting both influenza and Covid-19. The FDA’s decision follows significant changes to U.S. immunization policy under Health and Human Services Secretary Robert F. Kennedy Jr.

Moderna disputes the FDA’s reasoning, asserting that FDA rules do not mandate the use of the most advanced or highest-dose vaccine as a comparator in clinical studies. CEO Stéphane Bancel criticized the decision, emphasizing the importance of conducting a comprehensive review of a flu vaccine submission that uses an FDA-approved vaccine as a comparator as agreed upon with CBER.

Moderna anticipates potential approval for its flu shot in late 2026 or late 2027, pending regulatory reviews in the U.S., Europe, Canada, and Australia. The FDA has declined to comment on regulatory communications with individual sponsors.

Read more at CNBC: Moderna says FDA refuses to review application for flu shot