Moderna’s messenger ribonucleic acid (mRNA) influenza vaccine is effective, but uncertainties remain, Food and Drug Administration reviewers said in a document released on June 16. Data from a Phase 3 trial show the mRNA vaccine, known as mRNA-1010, had a “clinical benefit,” the reviewers said in the 92-page document. The trial compared the immunogenicity and clinical results in a group that received Moderna’s vaccine and compared the results to those from an arm that received an authorized, standard flu vaccine. The U.S. government, though, recommends a high-dose flu vaccine for adults aged 65 and older. “This limitation affects interpretation of the net clinical benefit in the 65 and older population and is a key issue for Advisory Committee deliberation,” the reviewers said....