Respiratory Syncytial Virus Maternal Vaccination in Infants below 6 Months of Age: Meta-Analysis of Safety, Immunogenicity, and Efficacy.

INTRODUCTION

Severe respiratory syncytial virus (RSV) disease is most prevalent during infancy, particularly in those born prematurely, who benefit least from maternal antibody transfers. Maternal immunization is an attractive prevention leading to vaccine clinical trials. This meta-analysis aimed to evaluate recent maternal RSV vaccine trials.

METHODS

Following PRISMA-P guidelines for systematic reviews and registered at <ext-link ext-link-type="uri" xlink:href="https://www.crd.york.ac.uk/prospero" xmlns:xlink="http://www.w3.org/1999/xlink">https://www.crd.york.ac.uk/prospero</ext-link>, this study shortlisted six randomized clinical trials of suitable quality from four databases. Meta-analysis evaluated vaccine safety, immunogenicity, and efficacy in infants and their mothers.

RESULTS

From random-effects and fixed-effects meta-analysis between trial and control arms, the maternal post-vaccination geometric antibody (Ab) titers showed pooled standard mean differences (SMDs [95% CI]) at delivery of (4.14 [2.91-5.37]), (3.95 [2.79-5.11]), and (12.20 [7.76, 16.64]) for RSV neutralizing Ab A, B, and F IgG, respectively. Vaccine administration was more likely than placebo to cause local pain, erythema, swelling, and systemic myalgia. Furthermore, the Ab levels in infants at birth showed pooled SMDs of each RSV A (3.9 [2.81-4.99]), RSV B (1.86 [1.09-2.62]), and RSV F IgG (2.24 [1.24-3.23]). The overall reduction of RSV-related lower respiratory tract infections and hospitalizations in the first 6 months of life was 52% and 48%, respectively.

CONCLUSIONS

Not only does antenatal RSV vaccination look safe and immunogenic in vaccinated mothers, but it also reliably provides effective antibody levels in infants and diminishes RSV-related severe disease in infants under 6 months of age.