• The FDA declined to review Moderna's application for its mRNA influenza vaccine.
• The refusal was based on the study using a suboptimal comparator flu vaccine.
• Moderna aims to clarify the FDA's requirements in a meeting.
• The decision has raised concerns regarding health policy under current leadership.
• Moderna's vaccine is still under consideration in the EU, Canada, and Australia.

The United States Food and Drug Administration (FDA) has formally refused to review Moderna's application for its mRNA influenza vaccine, citing that the company's late-stage study did not use what the agency deemed the "best-available standard of care" for comparison. Instead of comparing its new vaccine to a more suitable candidate, Moderna utilized a standard-dose flu shot in its trials, leading to an 8 percent drop in the company's shares following the announcement, according to Channel News Asia and CBS News.

In a "refusal-to-file" letter, the FDA did not cite any safety or efficacy concerns about the vaccine but questioned the adequacy of Moderna's study design. The letter indicated that the comparison was not aligned with FDA guidance, which states that vaccines should be tested against the best-available options available at the time of the study, as reported by AA and CBS News.

CEO Stephane Bancel expressed his disappointment at the decision, asserting that it contradicted previous communications with the FDA and emphasized that they had consulted with the agency prior to launching the study. Moderna has since requested an urgent meeting with FDA officials to seek clarification on the requirements for potential approval moving forward, according to Channel News Asia and AA.

The refusal is perceived as part of a broader pattern of heightened scrutiny of vaccine applications under current Health Secretary Robert F. Kennedy Jr., who has expressed skepticism about mRNA technologies. Critics have pointed out that his administration has canceled significant funding for mRNA vaccine projects, impacting the broader vaccine development landscape, as noted by CBS News and AA.