Cost-Effectiveness of Nirsevimab and Maternal RSVpreF Immunization Strategies in Low-Risk Infants

OBJECTIVE: In 2023, the Advisory Committee on Immunization Practices (ACIP) recommended both nirsevimab for infants aged less than 8 months and RSVpreF vaccine for pregnant patients at 32 to 36 weeks' gestation to prevent respiratory syncytial virus (RSV)-associated lower respiratory tract infections in infants. We compared the cost-effectiveness of the ACIP-recommended mixed nirsevimab and RSVpreF strategy vs a nirsevimab-only strategy for healthy, low-risk infants in the United States. METHODS: A decision tree with nested Markov models compared 3 immunization strategies for healthy low-risk infants: no immunization, a mixed strategy of RSVpreF and nirsevimab per ACIP guidelines, and nirsevimab only for all infants. We estimated health and societal outcomes using quality-adjusted life years (QALYs) and costs from a health care sector perspective (ie, direct medical costs) and a societal perspective (ie, factors like caregiver productivity loss). We assessed cost-effectiveness using incremental cost-effectiveness ratios (ICERs) and a willingness-to-pay threshold of $150 000/QALY to benchmark cost-effectiveness and conducted sensitivity analyses. RESULTS: From the health care sector perspective, neither the mixed strategy nor the nirsevimab-only strategy was cost-effective compared with no immunization, according to the $150 000/QALY threshold. From the societal perspective, the mixed strategy was cost-effective compared with no immunization ($117 848/QALY). Due to higher product costs, nirsevimab alone was not cost-effective compared with the mixed strategy ($347 821/QALY). However, if RSVpreF was not an option, the nirsevimab-only strategy would be cost-effective compared with no immunization ($134 391/QALY). Results were sensitive to assumptions about product costs and efficacy. CONCLUSION: Pediatricians and obstetricians should jointly recommend RSV immunizations, as the ACIP-recommended mixed RSVpreF and nirsevimab strategy is a societally cost-effective method to protect infants.