Cost-savings and health impact of strategies for prevention of Respiratory Syncytial Virus with nirsevimab in Chile based on the integrated analysis of 2019–2023 national databases: A retrospective study

Abstract

Background

In the latter half of 2023, the northern hemisphere initiated the rollout of nirsevimab immunization strategies for infants, yielding promising early results. As Chile prepared for its 2024 strategy implementation, we retrospectively evaluated the potential cost-saving nature of various immunization strategies.

Methods

Leveraging comprehensive inpatient, outpatient, and sentinel programs data, we conduct a simulation-based retrospective analysis to evaluate the net cost savings of various immunization strategies based on nirsevimab. We first characterize RSV burden among Chilean infants between 2019 and 2023, focusing on medically attended lower respiratory tract infections (MA LRTI), hospital admissions (HA LRTI), and severe cases requiring ICU admission (ICU LRTI). Utilizing nirsevimab efficacy estimates, we simulate counterfactual scenarios to estimate reductions in outpatient visits, hospitalizations, and ICU admissions had nirsevimab been used. We evaluate diverse immunization strategies and estimate their cost-saving status.

Findings

With nirsevimab costing about USD$225 per dose, immunizing infants under 6 months before the RSV season, all newborns during the season, and high-risk groups would have been cost-saving in 2023 and 2019. This strategy would have significantly decreased the strain on the healthcare system during the seasonal surge, reducing 13,533 ICU (77·81/1000 live newborns) and 27,465 hospital bed requirements (157·91/1000 live newborns), alongside 46,886 emergency room visits (269·58/1000 live newborns).

Interpretation

In Chile, a country with a GDP per capita of USD$17,000, various immunization strategies are cost-saving for scenarios comparable to pre-pandemic 2019 and to the particularly severe 2023 when considering only those direct costs associated with patient care, albeit differing in their impact in health outcomes. The resulting decrease in healthcare strain during the Winter virus surge underscores the strategy’s impact.