Phase 1/2 randomized, observer-blind clinical trial of a first-generation, mRNA-based vaccine against seasonal influenza and COVID-19 in healthy adults.
Amanda K Rudman Spergel, Carole Henry, Raffael Nachbagauer et al.
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In 30 seconds
This stratified, observer-blinded phase 1/2 randomized trial evaluated the safety and immune responses of a combined influenza and COVID-19 mRNA vaccine in healthy adults aged 18–75 years. Among 550 participants, mRNA-1073 was tested at three dose levels and compared with component vaccines given separately or together. Reactogenicity increased with dose, and most solicited reactions were mild or moderate. A single dose elicited immune responses lasting through 6 months against all vaccine-matched influenza and SARS-CoV-2 strains, with antibody profiles comparable to co-administered component vaccines.
Key findings
- The trial randomly assigned 550 healthy adults aged 18–75 years to combined-vaccine dose groups or component-vaccine comparators.
- mRNA-1073 reactogenicity was dose-dependent; most solicited adverse reactions were grade 1 or 2.
- No grade 4 events, vaccination-related serious adverse events, or deaths were reported.
- A single mRNA-1073 dose elicited immune responses through 6 months against all vaccine-matched influenza and SARS-CoV-2 strains.
Why it matters
A single vaccine intended to protect against seasonal influenza and COVID-19 could simplify immunisation by combining protection in one dose. These early clinical findings provide evidence that the tested formulation generated responses to both sets of vaccine-matched strains, while also characterising short-term safety and reactogenicity. The results inform further evaluation but do not establish clinical effectiveness against disease.
What to keep in mind
This phase 1/2 trial assessed safety and immunogenicity, not clinical protection against influenza or COVID-19 disease.