Impact and cost-effectiveness of two interventions to prevent paediatric respiratory syncytial virus disease in Cameroon: a modelling approach

Background: Preventive interventions for respiratory syncytial virus (RSV) disease are emerging and have been approved for support by Gavi, the Vaccine Alliance. However, their cost-effectiveness is under-researched in low- and middle-income countries, where RSV burden remains the highest. We modelled the potential impact and cost-effectiveness of two interventions for the prevention of RSV in young children in Cameroon, a Gavi-eligible country with a gross domestic product (GDP) per capita of USD 1563 in 2022. Methods: We used a static proportionate outcomes model to estimate the health and economic burden of RSV with and without a single dose of long-acting infant monoclonal antibody (mAb, nirsevimab) or maternal vaccine (bivalent RSVpreF) administered year-round over the period 2025-2034. We gathered data from the scientific literature, Demographic and Health Surveys, World Health Organization/UNICEF country profiles, clinical trials, and local experts. We calculated RSV cases, clinic visits, hospital admissions, and deaths for each week of age from birth to five years. The primary outcome measure was the incremental cost per disability-adjusted life year (DALY) averted from a government perspective, compared to no intervention. We explored cost-effectiveness over a range of cost-effectiveness thresholds expressed as proportions of the country's GDP per capita. Due to uncertainty in price per dose and limited country-specific RSV burden data, we ran several deterministic scenarios and performed probabilistic sensitivity analyses. Results: Between 2025 and 2034, we estimated that at USD 5 per dose, the infant mAb (69% coverage, 77% efficacy, 5 months protection) and maternal vaccine (65% coverage, 69% efficacy, 6 months protection) have a notable impact, averting 2267 (27.3%) and 2226 (26.9%) RSV-related deaths among children under five years old, respectively. In this scenario, the incremental cost was similar for both interventions (USD 500 per DALY averted) when compared separately to no intervention, with >90% probability of being cost-effective at a 0.5 GDP per capita (USD 782) threshold. To be cost-effective in Cameroon, at a 0.1 GDP per capita threshold, both interventions must be priced below USD 2.50. Conclusions: Both the infant mAb and maternal vaccine have the potential to be impactful and cost-effective in Cameroon and could be affordable if priced appropriately, with support from Gavi.