Modeled Impact of Nirsevimab for RSV Prophylaxis in the Public Healthcare System of Chile

OBJECTIVES: Respiratory Syncytial Virus (RSV) is a leading cause of severe respiratory infections and hospitalization in infants, with a significant impact on public health in Chile. Approximately 50% of children are infected by RSV in their first year, and nearly all have encountered the virus by age two. Severe RSV infections necessitate hospitalization in 2-3% of cases, leading to substantial healthcare demands. This study aims to evaluate the RSV-related health outcomes and costs of Nirsevimab compared to Best Supportive Care (BSC) in Chile, which includes Palivizumab prophylaxis for high-risk preterm infants and clinical management for other infants.

METHODS: We adapted a static decision model to the Chilean healthcare context, incorporating local epidemiological and cost data. The model included infants under one year, stratified into three subpopulations: Palivizumab-eligible, preterm, and term infants. Cost and health outcomes, including hospitalizations, ICU admissions, mechanical ventilation, emergency visits and outpatient visits, were modelled over one year. The analysis compared universal Nirsevimab immunization to the BSC.

RESULTS: The burden of RSV-related health events corresponds to 6,695 hospitalizations, 728 ICU admissions, 324 cases requiring mechanical ventilation, 21,572 emergency visits, and 54,594 outpatient visits, resulting in total costs of USD$50.5 million. Nirsevimab prevented 4,699 hospitalizations, 527 ICU admissions, 234 cases requiring mechanical ventilation, 14,002 emergency visits, and 33,274 outpatient visits. These reductions in health events led to total cost savings of USD$33.8 million, including USD$8.4 million in hospitalizations, USD$1.75 million in ICU admissions, USD$3.18 million in mechanical ventilation, USD$19.4 million in emergency visits, and USD$1.01 million in outpatient visits.

CONCLUSIONS: Universal immunization with Nirsevimab significantly reduces the clinical burden of RSV. The substantial health benefits and potential cost savings support the inclusion of Nirsevimab in the national immunization program, promising significant public health improvements.