Cost-effectiveness analysis of vitamin A supplementation delivery modalities in the DRC, Togo, and Niger: informing sustainable program design.

This study examines how the costs, health impacts, and efficiency of two-dose vitamin A supplementation (VAS) vary across delivery platforms, population subgroups, and delivery contexts in Togo, Niger, and the Democratic Republic of the Congo (DRC). Using a scenario-based model, it compares provider costs and disability-adjusted life years (DALYs) averted and identifies reallocations that maximize health gains under fixed budget constraints. Costs were estimated from the health provider perspective, and health outcomes were measured in DALYs averted. The results showed that cost-effective scenarios varied significantly across countries; in the DRC and Niger, campaigns delivered high coverage but at a substantially higher cost than routine delivery, whereas in Togo, campaigns were both low-cost and high-coverage. In all countries, the most cost-effective scenarios prioritized children aged 6-23 months. More than two-thirds of the cost-effective scenarios achieved better outcomes at lower cost than countries' current delivery strategies, highlighting significant potential for efficiency gains. A positive, nonlinear relationship between incremental costs and DALYs averted was observed: greater investment generally led to larger health gains but returns diminished as costs increased. A sensitivity analysis showed that facility-based supply shortages negatively affected effectiveness, whereas strengthened routine delivery improved effectiveness. Optimal VAS strategies must be context-specific, balancing the reach of campaigns with the sustainability of routine services. The decision tool provides a practical mechanism for identifying cost-effective delivery strategies tailored to national capacities and constraints.