Trends in Uncomplicated and Severe Malaria following Seasonal Malaria Chemoprevention Administration in Nouna, Burkina Faso

Abstract

Objective: To assess the ongoing population-level impact of Seasonal malaria chemoprevention (SMC) under routine program conditions by evaluating uncomplicated and severe malaria rates following the four rounds of SMC administration. Methods: We used data from a randomized controlled trial (RCT) of 285 villages in Nouna District, Burkina Faso, surveillance data of clinic visits and National Malaria Control Program data on SMC administration to calculate the malaria rates for each epidemiological week in 2021 for each health post in the study area. Negative binomial regression models were used with person-time used as offset and standard errors clustered by health post to obtain incidence rate ratios (IRRs) and rate differences estimating changes in diagnoses. Results: Although SMC was administered during malaria peak weeks, both uncomplicated and severe malaria rates were high through December, after the fourth/last round of SMC. There was substantial reduction in infection rates in the 3 weeks post SMC, with a slight increase in rates around the 3^rd week. Uncomplicated malaria rates were lower by 36%, 95%CI (24% - 45%), 37% (27% - 45%) and 23% (12% - 33%) in the first, second and third week after administration, respectively. Severe malaria rates lowered by 41% (14%-59%), 51% (32%-65%) and 25% (5%-40%) in the three weeks post-administration. Conclusion: Under routine program conditions, at the population level, SMC administration was associated with substantial reduction in uncomplicated and severe malaria but only in the immediate weeks post-administration. Assessment of local epidemiology and extension of the areas in which 5 rounds are distributed may be needed to effectively prevent malaria infections in areas with a longer transmission season.