Cost-Effectiveness Analysis of Nirsevimab for Respiratory Syncytial Virus Disease Prevention in Newborns of Hong Kong.

BACKGROUND: Nirsevimab, a long-acting monoclonal antibody, was shown to prevent respiratory syncytial virus (RSV) infections in newborns. We evaluated the cost-effectiveness of nirsevimab strategies for newborns from the societal perspective in Hong Kong. METHODS: A Markov model was developed to simulate outcomes of four nirsevimab strategies in newborns: (1) year-round, (2) seasonal, (3) catch-up, and (4) no nirsevimab. Primary outcomes included RSV lower respiratory tract infections (LRTI) related events, direct and indirect costs, quality-adjusted life year (QALY) loss, and incremental cost per QALY (ICER). RESULTS: In base-case analysis, all strategies with nirsevimab reduced RSV-LRTI-related events. The catch-up group had the lowest QALY loss per 100,000 infants (38.82), followed by year-round (45.71), seasonal (60.60), and no intervention groups (81.52). Three nirsevimab cost levels were examined: 10%, 25%, and 50% of the US cost. At 10% US cost (USD52), all strategies were cost-saving versus no intervention. At 25% US cost (USD130), the ICER of the catch-up group (vs. no intervention) was 141,925 USD/QALY. At 50% US cost (USD260), all nirsevimab strategies were not cost-effective versus no intervention at a willingness-to-pay of 162,401 USD/QALY. Influential factors with thresholds were identified for RSV-LRTI incidence, RSV-related hospitalization and mortality, and nirsevimab effectiveness at the 25% US cost level (USD130). In probabilistic sensitivity analysis, the catch-up and no intervention strategies were cost-effective 100% of the time at 10% (USD52) and 50% (USD260) US cost, respectively. At 25% US cost (USD130), the catch-up strategy was cost-effective 58.56% of the time. CONCLUSIONS: The cost-effectiveness acceptance of nirsevimab was highly subject to drug cost and effectiveness of nirsevimab, RSV-LRTI incidence, and RSV-LRTI-related consequences.