Moderna’s seasonal mRNA flu vaccine mRNA-1010 (mFLUSIVA) is under renewed FDA examination ahead of an upcoming Vaccines and Related Biological Products Advisory Committee meeting. FDA previously issued a refusal-to-file letter in February, but later reversed and accepted the application, narrowing the planned indications by age. Ahead of the adcom, FDA documents and briefing materials indicate the regulator and company appear aligned overall, while still flagging evidence gaps—reviewers note efficacy data is drawn from a single flu season and questions remain for immunocompromised and very frail older adults. The adcom review also reflects earlier concerns around comparator selection for older populations. The new phase of review will likely focus on whether submitted immunogenicity and clinical outcomes support efficacy across the requested age brackets and whether postmarketing plans address remaining uncertainties.