Effectiveness of Dihydroartemisinin-piperaquine as Seasonal Malaria Chemoprophylaxis in Extended High Transmission Settings of Tanzania: an Open Cluster Randomized Clinical Trial.

Background: Malaria prevalence has declined globally following the scale-up of the interventions, including insecticide-treated bed-net, indoor residual spraying, and prompt diagnosis and treatment with artemisinin-based combination therapy (ACT). Despite the gained success in the control, malaria has remained a major public health problem, particularly affecting children aged < 5 years in sub-Saharan Africa. Most of the malaria transmissions occur during the rainy season, a relatively short period. Intervention using antimalarial chemotherapy in children during the transmission season has been shown to prevent malaria-related morbidity and mortality. The World Health Organization has recommended seasonal malaria chemoprevention (SMC) using Sulphadoxine-pyrimethamine (SP) plus amodiaquine (AQ) in children aged 3-59 months in areas with highly seasonal malaria transmission. However, SP-AQ resistance is widespread in Tanzania. Therefore, this study will assess the effectiveness of Dihydroartemisinin-piperaquine (DHA-PQ) as SMC for the control of malaria among children in Tanzania.

Methods: Afebrile children aged 3-59 months from Nanyumbu and Masasi districts in the Mtwara region will be enrolled in an open cluster randomized clinical trial, administered monthly with a full course of DHA-PQ for three or four consecutive months during the high malaria transmission season of the three consecutive years. Three approaches of DHA-PQ SMC administration will be tested; a door-to-door approach using community health workers (CHWs), outreach visits using local health facilities clinicians/nurses, and village health posts using selected CHWs. Study participants will then be followed-up to evaluate the impact of the intervention on all-course of malaria morbidity and mortality; adverse events associated with the intervention; acceptability, adherence, coverage, and cost-effectiveness of the intervention; treatment-seeking behavior; and the risk of rebound after the withdrawal of the intervention. The primary outcome will be a prevalence of clinical malaria defined as the presence of fever (axillary temperature of 37.5 degrees Celsius) or a history of fever in the past 24 hours and the presence of P. falciparum asexual parasitemia at any density.

Findings: The findings will be disseminated through community meetings, seminars, local and international conferences, and publication in international journals.

Impact: The findings from this study will provide information on the effectiveness of DHA-PQ for seasonal prevention of malaria morbidity and mortality in children aged < 5 years in Tanzania.