A NEW multicomponent vaccine targeting both seasonal influenza and SARS-CoV-2 has demonstrated noninferior immunogenicity and acceptable safety in adults aged 50 years and older, according to results from a Phase III randomized trial. The investigational vaccine, mRNA-1083, produced comparable or superior immune responses to currently licensed vaccines and may offer a streamlined approach to immunization for this age group.
Conducted at 146 sites across the United States, the study enrolled over 8,000 participants in two cohorts: those aged 50–64 and those 65 and older. Participants received either the combined mRNA-1083 vaccine with placebo or the standard licensed quadrivalent influenza and COVID-19 vaccines coadministered. The primary aim was to establish noninferiority in humoral immune response to each component virus strain, measured 29 days post-vaccination. Secondary outcomes included evaluation of reactogenicity and superiority in immune response.
The results were promising. In both age groups, mRNA-1083 met the noninferiority threshold across all influenza and SARS-CoV-2 vaccine-matched strains. Among those aged 50–64, the vaccine induced superior antibody responses to all four influenza strains and to SARS-CoV-2. Among those 65 and older, mRNA-1083 outperformed high-dose influenza vaccine for three of four influenza strains, A/H1N1, A/H3N2, and B/Victoria, and SARS-CoV-2.
While solicited adverse reactions were more frequently reported after mRNA-1083 than comparator vaccines (83.5% vs 78.1% in ≥65 years and 85.2% vs 81.8% in 50–64 years), most reactions were mild to moderate and transient. No safety concerns were identified.
Given ongoing challenges with uptake of seasonal influenza and COVID-19 vaccinations, a single-dose option offering dual protection may improve adherence and streamline vaccine delivery in older adults. These findings support continued evaluation of mRNA-1083 as a practical and effective preventive tool in adult populations at higher risk for complications.
Reference:
Falsey AR et al. Immunogenicity and Safety of Influenza and COVID-19 Multicomponent Vaccine in Adults ≥50 Years. JAMA. 2025;333(22):1977-1987.
