mRNA-based seasonal influenza and SARS-CoV-2 multicomponent vaccine in healthy adults: a phase 1/2 trial.

Summary

In this randomized phase 1/2 study, the single-injection multicomponent mRNA-1083 vaccine showed acceptable reactogenicity and safety and elicited influenza and SARS-CoV-2 immune responses similar to or higher than licensed comparators by day 29. These data support phase 3 development and the feasibility of combined seasonal respiratory vaccination.

Key Findings

• Randomized phase 1/2 interim analysis (28 days) showed most solicited reactions were Grade 1–2; unsolicited AEs were similar across groups.
• mRNA-1083 induced influenza and SARS-CoV-2 immune responses comparable to or higher than licensed quadrivalent influenza and bivalent mRNA-1273 vaccines at day 29.
• Supports proceeding to phase 3 evaluation of combined seasonal respiratory vaccination.

Clinical Implications

If confirmed in phase 3, clinicians could offer a single annual mRNA dose covering influenza and SARS-CoV-2, reducing logistical burden and potentially improving coverage in older or multimorbid populations.

Limitations

• Short follow-up (28 days) without clinical efficacy endpoints.
• Sample size and detailed cohort numbers not provided in the abstract; durability and rare safety events remain unknown.

Future Directions

Proceed to phase 3 efficacy and durability testing across age strata, coadministration studies, and real-world effectiveness; evaluate variant-updated antigens and manufacturing scalability.