Study: Moderna’s mRNA-Based RSV Vaccine Causes High Rate of Adverse Reactions

The vaccine group suffered roughly 81 adverse events for every RSV illness the jab prevented.

Moderna logo in an illustration taken on May 3, 2022. Dado Ruvic/Illustration/Reuters

An mRNA vaccine for respiratory syncytial virus (RSV) developed by Moderna has caused higher adverse reactions compared to unvaccinated individuals in a clinical trial.

The study, published in the New England Journal of Medicine on Dec. 14, detailed a randomized test involving 35,541 individuals aged 60 years and older, out of which roughly half were given the mRNA-1345 vaccine (Moderna’s RSV vaccine) while the remaining received a placebo. The trials reported 95 cases of RSV among the placebo group and 29 cases among the vaccinated group, suggesting that the vaccine prevented 66 infections.