Analysis of the economically justifiable price of nirsevimab to prevent respiratory syncytial virus infection in Korea

The current standard-of-care prophylaxis for respiratory syncytial virus (RSV) is primarily administered to high-risk infant populations. We conducted a cost-effectiveness analysis to determine the economically justifiable price of nirsevimab compared with the standard of care in preventing medically attended RSV-associated lower respiratory tract infections from all infants and palivizumab-eligible children <2 years in South Korea. A month-age-specific static decision-tree model was used from a societal perspective, with a primary time horizon of one RSV season and an extended time horizon of three years. The model compared nirsevimab with standard of care prevention, which included palivizumab for eligible infants and children under two during the RSV season. The outcome measure was an incremental cost-effectiveness ratio (ICER) to suggest economically justifiable prices. The maximum economically justifiable price of nirsevimab was $527 at a 1 gross domestic product (GDP) per capita willingness-to-pay (WTP) threshold and $607 at a 1.5 GDP per capita WTP threshold per quality-adjusted life year (QALY) gain. The ICER was $33,071 per QALY at the price of $527 and $49,769 per QALY at $607 for the total population. Sensitivity analyses identified RSV epidemiology, nirsevimab effectiveness, and price as the key drivers of ICER variations. Probabilistic sensitivity analyses showed that nirsevimab was cost-effective at $527 in 55% of the simulations at the 1 GDP threshold and 54% at the 1.5 GDP threshold. Nirsevimab is estimated to be a cost-effective intervention for preventing RSV-associated lower respiratory tract infections within a universal immunization program for all infants and palivizumab-eligible children <2 years in South Korea.