Efficacy, Effectiveness, and Immunogenicity of the Respiratory Syncytial Virus Prefusion F Vaccine Administered During Pregnancy: Protocol for a Living Systematic Review and Meta-Analysis

Background

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract disease in infants, with the highest burden in the first 6 months of life. Maternal immunization with the bivalent (RSV-A and RSV-B) prefusion F (RSVPreF) protein subunit vaccine (ABRYSVO) is a recently recommended strategy for preventing RSV-related outcomes in infants. First licensed for use in pregnancy in 2023, the RSVPreF vaccine demonstrated efficacy in a single pivotal randomized trial (Maternal Immunization Study for Safety and Efficacy; MATISSE); postlicensure real-world evidence on vaccine effectiveness across settings, seasons, and subgroups and on antibody durability and transplacental transfer remains limited and has not been synthesized in a continuously updated framework, motivating this review.