Effectiveness of Maternal Respiratory Syncytial Virus Vaccination in Conferring Infant Immunity: Review and Future...

Respiratory syncytial virus (RSV) is a leading cause of acute lower respiratory tract infection in infants and young children worldwide and continues to impose a substantial disease burden despite recent advances in preventive strategies. Natural infection does not confer durable protective immunity, resulting in repeated reinfections, with the most severe disease occurring during early infancy. This review examines antibody-mediated prevention of RSV infection, with particular emphasis on vaccine development and maternal immunization. We reviewed current evidence on RSV pathogenesis, immune evasion, and antigenic characteristics relevant to vaccine design, focusing on viral surface glycoproteins targeted by preventive strategies. Recent data on licensed vaccines, long-acting monoclonal antibodies, and maternal immunization approaches were also evaluated. The RSV fusion (F) glycoprotein is the principal target of neutralizing antibodies and underpins currently licensed vaccines and monoclonal antibody products. Although circulating RSV strains show gradual antigenic evolution, primarily in the attachment protein, the F protein remains relatively conserved, resulting in only modest reductions in neutralization by human polyclonal sera over time. Constrained evolution of the F protein likely contributes to the sustained effectiveness of F-based interventions. However, waning F-specific neutralizing antibody titers contribute to susceptibility to reinfection, underscoring the importance of passive immunization strategies during early life. Maternal vaccination and long-acting monoclonal antibodies represent key advances in protecting young infants against RSV, but challenges remain in achieving equitable global implementation. Continued evaluation of antigenic evolution, the durability of protection, and optimization of maternal and infant immunization strategies will be critical for long-term disease control.