Key PointsQuestion Is a multicomponent vaccine against seasonal influenza and SARS-CoV-2 (mRNA-1083) immunogenic and well-tolerated in adults 50 years and older?Findings In this phase 3 study, mRNA-1083 elicited noninferior immune responses against standard care immunization: licensed standard-dose or high-dose seasonal influenza vaccine (A/H1N1, A/H3N2, B/Victoria, B/Yamagata) coadministered with licensed SARS-CoV-2 (Omicron XBB.1.5) vaccine. The multicomponent vaccine mRNA-1083 had an acceptab...