Abstract
Respiratory syncytial virus (RSV) remains a significant health burden in infants, with limited prevention options. Palivizumab, the monoclonal antibody (mAb) currently used for high-risk infants, requires a five-dose regimen, costing caregivers 47,260-642,000 Korean won (KRW) under the health insurance system, depending on the remaining season and infant's weight. Nirsevimab, the first approved long-acting RSV mAb, offers season-long protection with a single dose and costs 435,000-600,000 KRW. Direct cost comparisons indicate that nirsevimab might be more economical for infants born between April and November. Policy adjustments are needed to ensure equitable RSV protection through national immunization programs.