Background: Intermittent preventive treatment (IPT) of school-aged children with antimalarial drugs decreases rates of infection, anaemia, and clinical malaria. Since school-aged children are a major transmission reservoir, we estimated the effect of IPT for this group on Plasmodium falciparum transmission to younger children and adults across three epidemiological settings. Methods: Using an established malaria transmission model, three epidemiological archetypes (Sahelian, Central, and Southern African) were developed and the effect of IPT of school-age children was estimated across transmission levels (P. falciparum parasite rate in children aged 2–10 years [PfPR2–10]: 5–40%). Baseline interventions included long-lasting insecticide-treated nets and clinical case management. Scenarios compared three drug options (dihydroartemisinin–piperaquine, artesunate–amodiaquine, sulfadoxine–pyrimethamine–amodiaquine) with different delivery options. Findings: With frequent administration of long-acting drugs (monthly dihydroartemisinin–piperaquine), modelled IPT averted 70–90% of cases in school-aged children and 20–60% in younger children and adults, with greater benefit at lower transmission levels. Shorter-acting drugs administered with various schedules averted 40–60% of cases in school-aged children and 15–50% in other ages. Interpretation: Our model suggests that adding IPT of school-age children to current control tools could decrease malaria burden in this group and reduce P. falciparum transmission.
