Abstract
BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of respiratory tract infection in infants and young children. The level of serum neutralizing antibodies (SNAs) is often used as a measure of protection against respiratory syncytial virus (RSV) infection. METHODS: A qualified, model-based, meta-analysis efficacy prediction framework was used to understand the maternal vaccination-induced fold-increase in SNA titers necessary to achieve, over several study observation periods and study populations, similar protection to that of the monoclonal antibody clesrovimab (MK-1654). RESULTS: Simulations indicated that 3-month and 6-month efficacy comparable to that predicted for passive immunization (clesrovimab) would require a maternal vaccine to increase SNA titers by 30- and 60-fold, respectively, higher than observed increases reported to date. Efficacy of maternal vaccination was predicted (for vaccines similar to those with published data) to be substantially lower for preterm infants compared to full-term infants, and substantially less over 6 months than over 3 months. Efficacy of passive immunization was predicted to be similar or higher in preterm infants than full-term infants and was similar for 3- and 6-month observation periods. CONCLUSIONS: Modeling can be used to reliably predict the efficacy of maternal vaccination for preventing RSV in infants. Passive immunization (e.g., with clesrovimab) is likely to provide more protection for preterm infants and for infants born outside the RSV season than that provided by current maternal vaccines. Maternal vaccination may provide partial protection from RSV disease to full-term infants born just prior to or during the RSV season.