Title: The Effectiveness, Immunogenicity, and Safety of Maternal Respiratory Syncytial Virus (RSV) Vaccines: A Systematic Review and Meta Analysis 

Introduction: Globally, respiratory syncytial virus (RSV) is responsible for a considerable amount of illness and mortality in elderly adults and young children, with the highest impact in babies born prematurely. Maternal vaccination during pregnancy has been cited as a promising approach in the prevention of RSV-associated lower respiratory tract infections (LRTI) and RSV-associated hospitalizations in infants.

Aim: We aimed to synthesize randomized controlled trial data and provide a current update and overview of the efficacy and safety of all available maternal RSV vaccines.

Methods: We searched six databases-PubMed, Embase, Cochrane Library, Web of Science, Google Scholar, and ClinicalTrials.gov until January 15, 2024, for all randomized controlled trials (RCTs) that compared maternal and infant vaccinations against any placebo or a comparator. The meta-analysis used RevMan Web software and included six eligible RCTs that evaluated maternal RSV vaccine safety, immunogenicity, and efficacy in mothers and their infants.

Results: The analysis included six RCTs on maternal RSV vaccines (n = 12,652 mothers & n = 12,356 infants). The overall risk of bias and certainty of evidence was low. The findings revealed significant risk reduction in MA LRTI (RR: 0.50, 95% CI: 0.35, 0.71, p < 0.0001) and RSV-related hospitalizations (RR: 0.37, 95% CI: 0.18, 0.74, p = 0.005) in the first 6 months of life. Safety results showed significant differences in the incidence of adverse events between the two groups (RR: 1.08, 95% CI: 1.04, 1.12, p < 0.0001). Vaccinated groups were more likely than placebo groups to report injection site pain, swelling, and erythema. There was no significant difference in serious adverse events in infants (RR: 0.98, 95% CI: 0.93, 1.04, p = 0.52) and maternal participants (RR: 1.05, 95% CI: 0.97, 1.15, p = 0.23), and in adverse events in infants (RR: 1.03, 95% CI: 0.95, 1.12, p = 0.48).

Conclusion: Maternal RSV vaccines have a high safety profile and are effective in preventing RSV-associated LRTI and RSV-associated hospitalization in infants.

Keywords: Respiratory syncytial virus, vaccination, pregnancy, infants, safety, efficacy, meta-analysis

Chair: Dr. Ike Okosun