Work

Safety and Immunogenicity of an mRNA Respiratory Syncytial Virus Vaccine, mRNA-1345, in Healthy and High-Risk Pediatric Populations Aged 2 to 17 Years

Year: 2026

Type: article

Study designs: Randomized Controlled Trial, Clinical Trial

Abstract: Background: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections (LRTIs) in infants and children. No active RSV vaccine is currently available for children. mRNA-1345 is an investigational mRNA-based RSV vaccine encoding the prefusion F (preF) glycoprotein. Method: This phase 2, randomized, observer-blind study evaluated a single dose of mRNA-1345 in children aged 2 to <18 years who were healthy (2 to <5 years only) or had stable chronic conditions associated with increased RSV risk. Children aged 2 to <5 years received 7.5-, 15-, or 30-µg mRNA-1345 or placebo, whereas children aged 5 to <18 years received 15-, 30-, or 50-µg mRNA-1345. The primary objective was safety and reactogenicity (Part A); the secondary objective was immunogenicity. RSV surveillance was conducted from 6 to 12 months post-immunization in a subset of re-enrolled participants from the 2- to <5-year-old cohort (Part B). Results: Overall, 346 participants received study vaccination. Across dose levels and age cohorts, mRNA-1345 was well tolerated, with no vaccine-related serious adverse events or discontinuations. mRNA-1345 elicited robust increases in RSV-A and RSV-B neutralizing antibody titers and preF-biased responses by day 29. During Part B surveillance, RSV infections were infrequent, with no severe/hospitalized RSV-LRTIs. Conclusions: : NCT06097299.

Source: Open Forum Infectious Diseases

DOI: 10.1093/ofid/ofag679