Cost-Utility Analysis of an All-Preterm Infant Immunization With Nirsevimab Against Respiratory Syncytial Virus (RSV): Associated Disease at the Brazilian Private Healthcare System

OBJECTIVES: This study aims to estimate the cost-effectiveness of nirsevimab, a monoclonal antibody for the prevention of RSV lower respiratory tract disease (LRTD) in all-preterm, infants born <37 weeks of gestational age (GA) and special high-risk population (with comorbidities), compared to standard of practice (SoP) in the Brazilian private healthcare sector, during the first RSV season.

METHODS: Static model was developed to compare health and cost outcomes associated with nirsevimab use versus current SoP (palivizumab for babies <29 weeks of GA or no prophylaxis for babies 29-37 weeks of GA). Due to varying seasonality across Brazilian regions, data was harmonized, so prophylaxis corresponds to the same period at the cost-effectiveness model. Parameters were obtained from Brazilian databases DATASUS (SINASC, SIA-AIH and ANSTABNET), D-TISS panel, CMED, IBGE, and published articles. All costs were updated to present values, adjusted by National monetary correction indicator (IPCA), for January 31^st, 2024. The analysis horizon was defined as lifetime. Discount rates of 5% were applied. Parameters and assumption uncertainties were explored through sensitivity analyses.

RESULTS: The model estimated that 4,882 infants were palivizumab eligible in private healthcare sector. Using model with nirsevimab prophylaxis would protect additional 36,275 infants, preventing 906 hospitalizations (including 353 in ICU), 1,209 emergency department visits and 3,698 primary care visits. Nirsevimab would prevent 281 and 91 cases of recurrent wheezing and asthma, respectively. Nirsevimab prophylaxis would result an incremental cost to all payers combined of approximately 5.3 million BRL. However, it also yielded a gain of 195.6 QALY, resulting in an incremental cost-utility ratio of R$27,118/QALY. Deterministic and probabilistic sensitivity analyses showed consistent results.

CONCLUSIONS: Considering only direct medical costs, an all-preterm infant immunization with nirsevimab, when compared to the SoP, proved to be a cost-effective strategy in the Brazilian private sector.