Cost Effectiveness of Nirsevimab and Maternal RSVpreF Vaccine for Prevention of Respiratory Syncytial Virus Disease Among Infants in the United States

OBJECTIVES: This study evaluates the cost-effectiveness of year-round Respiratory Syncytial Virus (RSV) immunization strategies—nirsevimab and maternal RSVpreF vaccine—among the U.S. birth cohort, from a healthcare sector perspective.

METHODS: We developed a hybrid Decision Tree-Markov model to compare three strategies: year-round nirsevimab for newborns, year-round maternal RSVpreF vaccine for pregnant women, and standard care(no intervention). The decision tree predicted medically-attended RSV infections in infants’ first year, covering outpatient care, hospitalization, sequelae (recurrent wheezing, asthma), and death. The Markov model projected five-year sequelae outcomes for infants hospitalized due to RSV in their first year. Efficacy data was sourced from clinical trials, while quality-adjusted life-years (QALYs), costs (2024 USD), and other transition probabilities were derived from the literature. We calculated the Incremental Cost-Effectiveness Ratio (ICER) and Net Monetary Benefit (NMB) at the Willingness-to-Pay (WTP) threshold of $150,000/QALY. Deterministic and probabilistic sensitivity analyses were performed to assess the model uncertainty.

RESULTS: Compared to standard care, the maternal RSVpreF vaccine yielded an incremental cost of $62 per 0.00084 QALY gained per infant, resulting in an ICER of $73,823/QALY and an NMB of $64. The nirsevimab strategy incurred an extra $174 per 0.0012 QALY gain, leading to an ICER of $145,710/QALY and an NMB of $5. Comparing nirsevimab to RSVpreF, nirsevimab provided an additional 0.00035 QALY at an increased cost of $112, resulting in an ICER of $316,511/QALY. Probabilistic sensitivity analysis revealed a 92.21% and 90.95% probability of cost-effectiveness for nirsevimab and RSVpreF compared to standard care, respectively, at the WTP threshold of $150,000/QALY.

CONCLUSIONS: Both year-round maternal RSVpreF vaccine and nirsevimab are cost-effective RSV prevention strategies compared to standard care among the U.S. birth cohort at the WTP threshold of $150,000/QALY. However, nirsevimab is not cost-effective compared to RSVpreF at the WTP threshold of $150,000/QALY due to higher price ($519 vs. $295) and similar efficacy against severe RSV infection.