Evaluation of seasonal malaria chemoprevention in two areas of intense seasonal malaria transmission: Secondary analysis of a household-randomised, placebo-controlled trial in Houndé District, Burkina Faso and Bougouni District, Mali


Autoři: Matthew E. Cairns aff001;  Issaka Sagara aff002;  Issaka Zongo aff003;  Irene Kuepfer aff004;  Ismaila Thera aff002;  Frederic Nikiema aff003;  Modibo Diarra aff002;  Serge R. Yerbanga aff003;  Amadou Barry aff002;  Amadou Tapily aff002;  Samba Coumare aff002;  Paul Milligan aff001;  Halidou Tinto aff003;  Jean Bosco Ouédraogo aff003;  Daniel Chandramohan aff005;  Brian Greenwood aff005;  Abdoulaye Djimde aff002;  Alassane Dicko aff002
Působiště autorů: Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, United Kingdom aff001;  Malaria Research and Training Centre, Bamako, Mali aff002;  Institut de Recherche en Sciences de la Santé, Bobo Dioulasso, Burkina Faso aff003;  Swiss Tropical and Public Health Institute, Basel, Switzerland aff004;  Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom aff005
Vyšlo v časopise: Evaluation of seasonal malaria chemoprevention in two areas of intense seasonal malaria transmission: Secondary analysis of a household-randomised, placebo-controlled trial in Houndé District, Burkina Faso and Bougouni District, Mali. PLoS Med 17(8): e32767. doi:10.1371/journal.pmed.1003214
Kategorie: Research Article
doi: 10.1371/journal.pmed.1003214

Souhrn

Background

Seasonal malaria chemoprevention (SMC) is now widely deployed in the Sahel, including several countries that are major contributors to the global burden of malaria. Consequently, it is important to understand whether SMC continues to provide a high level of protection and how SMC might be improved. SMC was evaluated using data from a large, household-randomised trial in Houndé, Burkina Faso and Bougouni, Mali.

Methods and findings

The parent trial evaluated monthly SMC plus either azithromycin (AZ) or placebo, administered as directly observed therapy 4 times per year between August and November (2014–2016). In July 2014, 19,578 children aged 3–59 months were randomised by household to study group. Children who remained within the age range 3–59 months in August each year, plus children born into study households or who moved into the study area, received study drugs in 2015 and 2016. These analyses focus on the approximately 10,000 children (5,000 per country) under observation each year in the SMC plus placebo group. Despite high coverage and high adherence to SMC, the incidence of hospitalisations or deaths due to malaria and uncomplicated clinical malaria remained high in the study areas (overall incidence rates 12.5 [95% confidence interval (CI): 11.2, 14.1] and 871.1 [95% CI: 852.3, 890.6] cases per 1,000 person-years, respectively) and peaked in July each year, before SMC delivery began in August. The incidence rate ratio comparing SMC within the past 28 days with SMC more than 35 days ago—adjusted for age, country, and household clustering—was 0.13 (95% CI: 0.08, 0.20), P < 0.001 for malaria hospitalisations and deaths from malaria and 0.21 (95% CI 0.20, 0.23), P < 0.001 for uncomplicated malaria, indicating protective efficacy of 87.4% (95% CI: 79.6%, 92.2%) and 78.3% (95% CI: 76.8%, 79.6%), respectively. The prevalence of malaria parasitaemia at weekly surveys during the rainy season and at the end of the transmission season was several times higher in children who missed the SMC course preceding the survey contact, and the smallest prevalence ratio observed was 2.98 (95% CI: 1.95, 4.54), P < 0.001. The frequency of molecular markers of sulfadoxine-pyrimethamine (SP) and amodiaquine (AQ) resistance did not increase markedly over the study period either amongst study children or amongst school-age children resident in the study areas. After 3 years of SMC deployment, the day 28 PCR-unadjusted adequate clinical and parasitological response rate of the SP + AQ regimen in children with asymptomatic malaria was 98.3% (95% CI: 88.6%, 99.8%) in Burkina Faso and 96.1% (95% CI: 91.5%, 98.2%) in Mali. Key limitations of this study are the potential overdiagnosis of uncomplicated malaria by rapid diagnostic tests and the potential for residual confounding from factors related to adherence to the monthly SMC schedule.

Conclusion

Despite strong evidence that SMC is providing a high level of protection, the burden of malaria remains substantial in the 2 study areas. These results emphasise the need for continuing support of SMC programmes. A fifth monthly SMC course is needed to adequately cover the whole transmission season in the study areas and in settings with similar epidemiology.

Trial registration

The AZ-SMC trial in which these data were collected was registered at clinicaltrials.gov: NCT02211729.

Klíčová slova:

Burkina Faso – Epidemiology – Hospitals – Malaria – Malarial parasites – Mali – Parasitic diseases – Plasmodium


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2020 Číslo 8

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