Respiratory Syncytial Virus Prophylaxis: Maternal Vaccination or Long-Acting Monoclonal Antibodies? A Brief Narrative Review of Current Status

Respiratory syncytial virus (RSV) remains a leading cause of severe lower respiratory tract infection in early infancy, with the highest burden concentrated in the first months of life. Two immunoprophylactic strategies—maternal RSVpreF vaccination and long-acting monoclonal antibodies—now offer effective early life protection, yet differ in biological mechanisms, operational requirements, and programmatic implications. Maternal vaccination induces high-quality neutralizing antibodies that are transferred transplacentally, providing immediate protection from birth and integrating efficiently into antenatal care platforms. However, its effectiveness is constrained by gestational timing, physiological antibody waning, and reduced protection when vaccination occurs shortly before delivery. Long-acting monoclonal antibodies, including nirsevimab and clesrovimab, bypass maternal immune variability and provide standardized, season-long protection across gestational ages, including preterm infants. Economic evaluations demonstrate that both strategies can be cost-effective, though their relative value depends on local epidemiology, pricing, and coverage patterns. Economic outcomes for monoclonal antibodies and maternal vaccination are highly context-dependent and influenced by regional RSV epidemiology, healthcare utilization, product pricing, and implementation capacity, rather than universally favoring one strategy over the other. Global equity considerations remain critical: disparities in antenatal care access, supply chain fragility, and pricing differentials may widen gaps between high- and low-income countries. Remaining evidence gaps—including long-term safety monitoring, durability of protection, viral evolution, and implementation challenges—underscore the need for continued research and careful integration of these tools into national immunization programs.