A Phase 1/2 Dose-Ranging Safety and Immunogenicity Study of mRNA-Based Candidate Pandemic Influenza Vaccines in Healthy Adults.
Catherine A Cosgrove, Andrei Avanesov, Dondi Rust et al.
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In 30 seconds
This randomised phase 1/2 dose-ranging study evaluated the safety, reactogenicity, and immunogenicity of mRNA-1018 pandemic influenza vaccine candidates in healthy adults. Part A included H5- or H7-based candidates at three dose levels, while Part B evaluated an H5-only candidate. Across candidates and doses, 76.8% of participants reported solicited local adverse reactions within 7 days, most commonly injection-site pain; 62.8% reported systemic reactions, most often fatigue and headache. Immune responses generally increased with dose, and H5-based candidates produced stronger strain-specific HAI responses.
Key findings
- Parts A and B included 1195 and 304 dosed participants, respectively.
- Solicited local adverse reactions within 7 days occurred in 76.8% of participants; injection-site pain was most common.
- Solicited systemic adverse reactions occurred in 62.8% of participants, most frequently fatigue and headache.
- Immune responses tended to increase with dose, and H5-based candidates induced stronger strain-specific HAI responses.
Why it matters
Pandemic influenza vaccines need to generate immune responses while maintaining acceptable tolerability. These early-phase findings suggest that mRNA candidates targeting H5 and H7 can elicit measurable responses in healthy adults, with dose-related trends and stronger HAI responses for H5-based candidates. The results support continued evaluation but do not establish protective efficacy.
What to keep in mind
The study assessed safety and immunogenicity rather than clinical protection against influenza; the abstract does not report vaccine efficacy.