Efficacy and Safety of Vaccines to Prevent Respiratory Syncytial Virus Infection in Infants and Older Adults: A Systematic Review and Meta-analysis

Objectives To determine the efficacy and safety of respiratory syncytial virus (RSV) vaccines in infants and older adults. Methods We performed a systematic review and meta-analysis of randomized control trials that evaluated the efficacy of maternal RSV immunization against infections in infants, as well as the efficacy of RSV vaccines in older adults. The primary outcome was the vaccine efficacy against RSV-related lower respiratory tract disease (LRTD). GRADE criteria was used to evaluate the level of evidence. Results Ten trials were included in the review. For maternal vaccination, the RSV vaccine showed favourable efficacy against RSV-related LRTD (vaccine efficacy 57.3%, 95% CI 31.3 to 73.5; low certainty) and RSV-related severe LRTD (vaccine efficacy 81.9%, 95% CI 56.8 to 92.4; moderate certainty) in infants within 90 days after birth. For older adults, Meta-analysis showed that RSV vaccines could also reduce the risk of RSV-related LRTD (vaccine efficacy 78.3%, 95% CI 65.6 to 86.3; moderate certainty) and RSV-related severe LRTD (vaccine efficacy 86.5%, 95% CI 68.3 to 94.3; moderate certainty). There was no significant difference in serious adverse events between RSV vaccines and placebo. Conclusion RSV vaccines have the potential to offer protection against RSV disease in both infants and older adults, without apparent safety concerns.