Impacts of Seasonal Mass Drug Administration in School-Aged Children on Chronic Malaria Infections in Burkina Faso.

School-aged children constitute an important asymptomatic reservoir for Plasmodium and may harbor the parasite through malaria transmission seasons in the absence of treatment. As WHO guidelines do not recommend chemoprevention for this group, there is a need to understand how such interventions could impact malaria transmission dynamics. This study investigated seasonal transmission patterns and the potential of mass drug administration (MDA) at the onset of the dry season to interrupt malaria transmission. Monthly parasitological surveys were conducted in Burkina Faso rural localities during the dry season targeting two cohorts of school-aged children: one of children uninfected at baseline who received no treatment and another of parasitemic asymptomatic children who received a full treatment dose of artemether-lumefantrine. Monthly blood samples were collected and analyzed using microscopy and polymerase chain reaction. Parasite diversity and drug resistance were assessed with msp1/msp2 typing and pfcrt/pfmdr1 genotyping, and entomological monitoring evaluated mosquito vector dynamics and infection status. Our results revealed that 93% of uninfected individuals remained Plasmodium infection free. Among treated individuals, 91% remained negative during follow-up. The prevalence of persistent infections among parasitemic individuals was stable over time at 5-9% in both cohorts. msp1/msp2 genotyping revealed the same haplotypes over time within participants, and analysis of drug-resistance markers showed low frequencies of mutations associated with antimalarial resistance. Our findings demonstrated that malaria transmission is interrupted during the dry season and that early MDA can effectively prevent infection, with over 90% of participants remaining parasite free, highlighting its potential to disrupt transmission dynamics.