Ahead of a June advisory committee hearing, the FDA and external documents indicate regulators are broadly open to Moderna Inc.’s mRNA-1010 seasonal flu vaccine, after a prior refusal-to-file letter in February. The FDA now appears aligned with the company’s application trajectory, though it flagged specific uncertainties for review. Jefferies and briefing materials cited by the story point to a key evidence gap: clinical efficacy data are based on a single flu season, and performance in immunocompromised and very frail older adults has not been established. Moderna is seeking full approval for ages 50–64 and accelerated approval for adults 65 and older. The advisory meeting keeps the program’s timeline in focus, with regulators weighing immunogenicity and safety across age cohorts while clarifying remaining efficacy questions before the FDA’s decision window.