Effectiveness of seasonal malaria chemoprevention (SMC) treatments when SMC is implemented at scale: Case-control studies in 5 countries.

Autor: Matthew Cairns, Serign Jawo Ceesay, Issaka Sagara, Issaka Zongo, Hamit Kessely, Kadidja Gamougam, Abdoulaye Diallo, Johnbull Sonny Ogboi, Diego Moroso, Suzanne Van Hulle, Tony Eloike, Paul Snell, Susana Scott, Corinne Merle, Kalifa Bojang, Jean Bosco Ouedraogo, Alassane Dicko, Jean-Louis Ndiaye, Paul Milligan
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: PLoS Medicine, Vol 18, Iss 9, p e1003727 (2021)
Druh dokumentu: article
ISSN: 1549-1277
1549-1676
DOI: 10.1371/journal.pmed.1003727
Popis: BackgroundSeasonal malaria chemoprevention (SMC) has shown high protective efficacy against clinical malaria and severe malaria in a series of clinical trials. We evaluated the effectiveness of SMC treatments against clinical malaria when delivered at scale through national malaria control programmes in 2015 and 2016.Methods and findingsCase-control studies were carried out in Mali and The Gambia in 2015, and in Burkina Faso, Chad, Mali, Nigeria, and The Gambia in 2016. Children aged 3-59 months presenting at selected health facilities with microscopically confirmed clinical malaria were recruited as cases. Two controls per case were recruited concurrently (on or shortly after the day the case was detected) from the neighbourhood in which the case lived. The primary exposure was the time since the most recent course of SMC treatment, determined from SMC recipient cards, caregiver recall, and administrative records. Conditional logistic regression was used to estimate the odds ratio (OR) associated with receipt of SMC within the previous 28 days, and SMC 29 to 42 days ago, compared with no SMC in the past 42 days. These ORs, which are equivalent to incidence rate ratios, were used to calculate the percentage reduction in clinical malaria incidence in the corresponding time periods. Results from individual countries were pooled in a random-effects meta-analysis. In total, 2,126 cases and 4,252 controls were included in the analysis. Across the 7 studies, the mean age ranged from 1.7 to 2.4 years and from 2.1 to 2.8 years among controls and cases, respectively; 42.2%-50.9% and 38.9%-46.9% of controls and cases, respectively, were male. In all 7 individual case-control studies, a high degree of personal protection from SMC against clinical malaria was observed, ranging from 73% in Mali in 2016 to 98% in Mali in 2015. The overall OR for SMC within 28 days was 0.12 (95% CI: 0.06, 0.21; p < 0.001), indicating a protective effectiveness of 88% (95% CI: 79%, 94%). Effectiveness against clinical malaria for SMC 29-42 days ago was 61% (95% CI: 47%, 72%). Similar results were obtained when the analysis was restricted to cases with parasite density in excess of 5,000 parasites per microlitre: Protective effectiveness 90% (95% CI: 79%, 96%; PConclusionsSMC administered as part of routine national malaria control activities provided a very high level of personal protection against clinical malaria over 28 days post-treatment, similar to the efficacy observed in clinical trials. The case-control design used in this study can be used at intervals to ensure SMC treatments remain effective.
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