Public health impact of current and proposed age-expanded perennial malaria chemoprevention: a modelling study

In 2022, the World Health Organization extended their guidelines for perennial malaria chemoprevention (PMC) from infants to children up to 24 months old. However, evidence for PMC’s public health impact is primarily limited to children under 15 months. Further research is needed to assess the public health impact and cost-effectiveness of PMC, and the added benefit of further age-expansion. We integrated an individual-based model of malaria with pharmacological models of drug action to address these questions for PMC and a proposed age-expanded schedule (PMC+, for children 03-36 months). Across prevalence settings of 5-70% and different drug sensitivity assumptions, we predicted PMC and PMC+’s median efficacy of 18.6%(12.2-25.0%) and 21.9%(14.3-29.5%) against clinical disease and 9.0%(2.0-16.0%) and 10.8%(3.2-18.4%) against severe malaria, respectively, in children under three years. PMC’s total impact outweighed risk of delayed malaria in children up to age five and remained cost-effective when delivered through the Expanded Program on Immunization.