Evaluation of direct and indirect effects of seasonal malaria chemoprevention in Mali

Thomas Druetz

doi:10.1038/s41598-018-26474-6

Thomas Druetz

Open Access

https://doi.org/10.1038/s41598-018-26474-6

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Journal: Scientific Reports	Publication Date: May 25, 2018
Citations: 34	License type: open-access

Affiliation: Université de Montréal, Tulane University

Abstract

Randomized controlled trials have established that seasonal malaria chemoprevention (SMC) in children is a promising strategy to reduce malaria transmission in Sahelian West Africa. This strategy was recently introduced in a dozen countries, and about 12 million children received SMC in 2016. However, evidence on SMC effectiveness under routine programme conditions is sparse. We aim to measure the effects of the nationwide SMC programme in Mali on the prevalence of malaria and anemia in children 6–59 months. We used data from the 2015 nationally representative malaria indicator survey. A post-test only with non-randomized control group study was designed. We fitted a generalized structural equation model that controlled for potential bias on observed and non-observed variables (endogenous treatment effect model). Having received SMC reduced by 44% (95% CI [0.39–0.49]) the risk of having a positive rapid diagnostic test for malaria. In addition, the programme indirectly reduced by 18% the risk of moderate-to-severe anemia (95% CI [0.15–0.21]). SMC in Mali has substantial protective effects under routine nationwide programme conditions. Endogenous treatment effects analyses can contribute to rigorously measuring the effectiveness of health programmes and to bridging a widening gap in evaluation methods to measure progress towards achieving malaria elimination.

Highlights

Seasonal malaria chemoprevention (SMC) is a promising strategy to reduce the burden attributable to malaria in children under five
An ecological study conducted in Mali with a similar quasi-experimental design found that SMC reduced the odds of malaria infection at the district level by two thirds at the end of the transmission season[16]
Exposure to SMC was statistically significantly associated with variables at higher levels: mother’s education, household’s size, socio-economic status, religion, number of bed nets, and cluster altitude and region

Summary

Introduction

Seasonal malaria chemoprevention (SMC) is a promising strategy to reduce the burden attributable to malaria in children under five. Trials suggested a beneficial effect on anemia[7,8] Based on this evidence, the WHO has been recommending SMC since 2012, and it has been introduced in a dozen Sahelian or sub-Sahelian countries[12,13]. An ecological study conducted in Mali with a similar quasi-experimental design found that SMC reduced the odds of malaria infection at the district level by two thirds (OR 0.35, 95% CI 0.19–0.66) at the end of the transmission season[16]. These studies were limited to small study areas and have limited external validity. Number Female Mean age in months (SD) Slept under a bed net the night before Mothers’ education None Primary Secondary or higher Ethnic group Bambara Peulh/Toucouleur Other SES Poorest Poorer Medium Richer Richest Size of the household 1–5 6–10 ≥10 Muslim Mean number of bed nets (SD) Cluster altitude in meters (SD)

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