Assessing Carbon Emissions of an Immunization Program Against Respiratory Syncytial Virus in Infants in France

OBJECTIVES: Respiratory Syncytial Virus (RSV) significantly impacts children <2 years-old, often causing bronchiolitis during its epidemic peak in France (November to February). The novel preventive treatment, nirsevimab, is indicated for all infants entering their first RSV season. This study aims to evaluate the associated net carbon emissions, comparing nirsevimab with standard of care (SoC) in terms of patient care pathways and healthcare utilization.

METHODS: The study assesses immunization against RSV in infants under one year of age in France. Avoided RSV-related events from five health outcomes, ranging from primary care visits to ICU admissions, were calculated, using data from cost-effectiveness model comparing nirsevimab with SoC. Carbon emissions, measured in kilotons (kt) of CO2 equivalent (CO2eq), were estimated by including several emissions factors from the production of nirsevimab (using a monoclonal antibody proxy of 150mg), administration, healthcare utilization and patient travel. Further research is required to incorporate a full life cycle assessment of nirsevimab and to gather more representative carbon emissions data from hospitals across France. Moreover, since hospitalizations are not exclusive to RSV, obtaining more detailed and specific data is crucial to improve this innovative approach. Scenarios for the 2023-2024 and 2024-2025 seasons projected immunization for 250,000 and ~600,000 infants, respectively.

RESULTS: Inpatient hospitalizations and primary care visits represent the largest part of avoided emissions in each nirsevimab season scenario. Compared with SoC, the RSV immunization program using nirsevimab was found to avoid substantial carbon emissions amounting to a net avoided ~13.92ktCO2eq/year in the 2023-2024 season scenario and ~24.82ktCO2eq/year in the 2024-2025 season scenario. This represents 0.03 to 0.05% of healthcare-related emissions in France (49MtCO2eq), for a single healthcare product.

CONCLUSIONS: Nirsevimab considerably reduces the incidence of RSV infections and healthcare-related carbon emissions and highlighting immunization’s role in decarbonizing healthcare systems. Emissions avoided during patient care help to reduce production emissions.