Effect of malaria chemoprevention for school-age children across transmission archetypes: a modelling study.

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: With the use of an established malaria transmission model, we developed three epidemiological archetypes (Sahelian, Central, and Southern African) and estimated the effect of IPT of school-age children across transmission levels (P falciparum parasite rate in children aged 2-10 years [PfPR2-10]: 5-40%). Long-lasting insecticide-treated nets and clinical case management were always included as baseline interventions. We compared scenarios for three of the most widely studied drug options (dihydroartemisinin-piperaquine, artesunate-amodiaquine, and sulfadoxine-pyrimethamine-amodiaquine) and delivery options (school-based or community-based), estimating clinical cases averted. FINDINGS: When long-acting drugs were administered frequently (monthly campaigns with dihydroartemisinin-piperaquine), modelled IPT of school-age children averted 70-90% of cases in school-aged children (up to about 2·0 cases per child per year) and 20-60% of cases in younger children and adults (up to about 0·5 cases per person per year), with greater community benefit at lower transmission levels (PfPR2-10 5-10%). Shorter-acting drugs (sulfadoxine-pyrimethamine-amodiaquine in the Sahelian archetype or artesunate-amodiaquine in the Central and Southern archetypes) administered monthly or longer-acting drugs administered once per school term averted 40-60% of cases in school-aged children (up to about 1·3 cases per child per year) and 15-50% of cases in other ages (up to about 0·5 cases per person per year). 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. FUNDING: US National Institutes of Health, Doris Duke Clinical Scientist Development Award.