Passive Immunization Strategies to Prevent Severe Respiratory Syncytial Virus Infection Among Newborns and Young Infants.

This article focuses on strategies for preventing severe respiratory syncytial virus (RSV) lower respiratory tract infection in newborns and young infants through passive immunity. It details the role of transplacental transfer of maternal antibodies, influenced by factors such as gestational age and maternal health, and highlights maternal immunization as a method to enhance neonatal protection. The article reviews three maternal RSV vaccine candidates targeting the RSV fusion (F) protein, noting that Pfizer Inc.'s RSVpreF vaccine (Abrysvo) received FDA approval in 2023 for administration during 32 to 36 weeks gestation to prevent RSV disease in infants. Additionally, it discusses passive immunization via RSV-specific monoclonal antibodies, particularly palivizumab, which is approved for high-risk infants. The review underscores benefits and limitations of these approaches, including vaccine safety considerations and barriers to maternal immunization uptake.