Cost-Effectiveness Analysis of Nirsevimab for the Prevention of Respiratory Syncytial Virus among Italian Infants.

Background and objective: Respiratory syncytial virus (RSV) is a major global cause of childhood respiratory infections, globally linked to significant morbidity and mortality, particularly leading in hospitalizations and death among infants below 1 year of age. A cost-effectiveness analysis was conducted to estimate the economically justifiable price (EJP) of nirsevimab, a new prophylaxis strategy protecting all infants against RSV lower respiratory tract infections (LRTIs), compared with a strategy consisting of palivizumab, protecting only high-risk infants and no preventive intervention for others.

Methods: A static decision tree model previously published to evaluate the clinical and economic burden of RSV in Italy was used to determine the EJP of nirsevimab for the prevention of RSV medically attended lower respiratory tract infections (RSV-MA-LRTIs) in all infants experiencing their first RSV season, to become a cost-effective alternative compared with palivizumab only in high-risk infants and no preventive intervention for others. The EJP was estimated considering three different willingness-to-pay (WTP) thresholds. The National Health Service (NHS) perspective was considered in the base-case. Direct costs considered in the analysis were acquisition and administration costs of prophylaxis, costs of managing RSV infection (inpatient and outpatient care, and emergency department visits) and costs of handling complications following hospitalization per RSV event. Indirect costs were evaluated in the scenario analysis as productivity loss due to premature death for RSV infection. A discount rate of 3.0% was applied only to mid-long-term costs and outcomes.

Results: From the NHS perspective, over the first RSV season, nirsevimab in an all-infants population could be a cost-effective approach compared with palivizumab only in high-risk infants, with an EJP equal to €267, €365, and €400 considering a WTP threshold of €0, €22,000, and €30,000 per QALY saved, respectively. Considering only the palivizumab-eligible population, the model estimated that nirsevimab could be a cost-effective approach with an EJP equal to €3,467, €3,633, and €3,694 considering a WTP threshold of €0, €22,000, and €30,000 per QALY saved, respectively.

Conclusions: A prophylaxis strategy against RSV infection targeting all infants with nirsevimab could represent a cost-effective option for both NHS and societal perspectives, and supports the implementation and the equity of RSV prevention for all infants.