Modelling the potential clinical and economic impact of universal immunisation with nirsevimab versus standard of practice for protecting all neonates and infants in their first respiratory syncytial virus season in Spain

Abstract

Abstract Background Respiratory syncytial virus (RSV) is associated with substantial morbidity among infants. This study modelled the potential public health and economic impact of nirsevimab, a long-acting monoclonal antibody, as an immunoprophylactic strategy for all infants in Spain in their first RSV season. Methods A static decision-analytic model of the Spanish birth cohort during its first RSV season was developed to estimate the impact of nirsevimab on RSV-related health events and costs versus the standard of practice (SoP). Spain-specific costs and epidemiological data were used as model inputs. Modelled outcomes included RSV-related outpatient visits, emerging room (ER) visits, hospitalisations – including pediatric intensive care unit (PICU) admission, mechanical ventilation, and inpatient mortality. Results Under the current SoP, RSV caused 145104 primary care visits, 37978 ER visits, 12911 hospitalisations, 1415 PICU admissions, and 17 deaths over a single season, representing a cost of €68.4 million from a healthcare payer perspective. Universal immunisation of all infants with nirsevimab was expected to prevent 99433 primary care visits (68.5% reduction), 26030 ER visits (68.5%), 8754 hospitalisations (67.8%), 934 PICU admissions (66.0%), and 9 inpatient deaths (56.5%), saving €45.6 million (66.7%) in healthcare costs. Conclusions These results suggest that immunisation with nirsevimab of all infants experiencing their first RSV season in Spain is likely to prevent thousands of RSV-related health events and save considerable costs versus the current SoP.