NEJM publishes Phase 3 results of Moderna's mRNA RSV vaccine in adults 60 and older

Moderna/Respiratory vaccines

NEJM published the Phase 3 trial of mRNA-1345 in 35,541 adults aged 60+. After a median 3.7 months it was 83.7% effective against RSV lower respiratory disease with two or more symptoms and 82.4% with three or more, covering both RSV subtypes.

• mRNA-1345 encodes a stabilised prefusion F glycoprotein from RSV surface.
• Efficacy remained consistent across both RSV subtypes (A and B); 82.4% at ≥3 symptoms is clinically meaningful threshold.
• Median follow-up 3.7 months; adverse reactions more common in vaccine group but mostly transient and mild-moderate.
• 2.8% severe adverse events in both groups; safety profile acceptable for elderly population.