Optimizing risk factors to guide COST‐effective use of palivizumab in KOREAN infants

BACKGROUND: Korean infants born at 32-35 weeks gestational age (wGA) receive palivizumab prophylaxis to prevent respiratory syncytial virus hospitalization (RSVH) if they are born during the RSV season and have a sibling. The aim of this study was to evaluate the impact of using the International Risk Scoring Tool (IRST) to target prophylaxis in Korea. METHODS: The IRST includes 3 risk factors: birth 3 months before to 2 months after the RSV season starts; smokers in the household and/or smoking while pregnant; and, siblings/daycare. First, the accuracy of the Korean guidelines to predict RSVH was compared to that of the IRST using a historic dataset of 13,475 infants born 32-35 wGA. Second, a published cost-utility model was adapted using Korean-specific parameters for costs (2022) and resource use to assess the cost-effectiveness of palivizumab versus no prophylaxis guided either by the Korean guidelines or the IRST. RESULTS: Using the Korean guidelines identified 26.9% of RSVHs, with an area under the receiver operating characteristic curve of 0.512. The corresponding results for infants assessed at moderate- to high-risk by the IRST were 85.1% and 0.773, respectively. The incremental cost per quality-adjusted life year (QALY) for prophylaxis versus no prophylaxis was ₩29,674,102 (USD22,977) using the Korean guidelines, with a 67.0% probability for cost-effectiveness against a willingness-to-pay threshold of ₩41,655,203 (USD32,255). For the IRST, it was ₩26,265,142 (USD20,338)/QALY and 70.8% probability. CONCLUSIONS: Adoption of the IRST in Korea would provide greater protection of the most vulnerable infants born 32-35 wGA against RSVH whilst improving cost-effectiveness.