Sanogo Daouda, Toure Mahamoudou, Keita Moussa, Kane Fousseyni, Keita Soumba, Sanogo Ibrahima, Diawara Sory Ibrahim, Tangara Cheick Oumar, Coulibaly Hamady, Cisse Bourema, Thiam Sidibé M'Baye, Diakite Mahamadou, Sogoba Nafomon, Doumbia Seydou
West African International Center for Excellence in Malaria Research (WAF ICEMR), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.
University Clinical Research Center (UCRC), University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.
Malar J. 2025 Mar 27;24(1):102. doi: 10.1186/s12936-025-05283-z.
Seasonal malaria chemoprevention (SMC) with sulfadoxine-pyrimethamine and amodiaquine (SP + AQ) involves the monthly administration of therapeutic doses to children under five years of age during periods of high risk of malaria in regions where malaria transmission is highly seasonal. Current SMC guidelines recommend administering the same treatment to both non-infected and asymptomatic Plasmodium falciparum-infected children. However, a critical knowledge gap remains the impact asymptomatic infection on the efficacy of SMC in preventing clinical malaria over a four-week period. This study aimed to evaluate the risk of clinical malaria and its association with children's infection status during SMC treatment.
This study was conducted in the Koulikoro health district of Mali and focused on children under 10 years of age. A total of 726 children in 2019 and 1452 children in 2020 were randomly selected and followed throughout the SMC campaigns. The prevalence of asymptomatic P. falciparum infection was assessed in each round using microscopy prior to SMC drug administration. Children were passively monitored over a four-week period to record the incidence of clinical malaria. Data analysis was performed using R-Studio software. The risk of clinical malaria based on infection status was estimated through logistic regression analysis, and a Kaplan-Meier curve was used to compare survival times between infected and uninfected children. Proportions were compared using the Pearson Chi-square test, with statistical significance set at p < 0.05.
The average prevalence of asymptomatic P. falciparum infection was 11.0% across study years. Prevalence was notably higher among children aged 5 to 9 years old in 2019 (p < 0.001) and 2020 (p = 0.016). Asymptomatic infected children had a significantly higher risk of clinical malaria during both transmission seasons: 2019: (RR = 3.05, CI [2.04-4.72]) and 2020 (RR = 1.43, CI [1.04-1.97]). Furthermore, the time to the first malaria episode was significantly shorter among infected children in both years (p < 0.001 for 2019, p = 0.01 for 2020).
These findings demonstrate an elevated risk of clinical malaria in asymptomatic infected children during SMC implementation. Screening and treating P. falciparum infections prior to SMC administration could substantially enhance the effectiveness of this strategy in reducing malaria morbidity in endemic areas.
使用磺胺多辛-乙胺嘧啶和阿莫地喹（SP + AQ）进行季节性疟疾化学预防（SMC），是指在疟疾传播高度季节性的地区，在疟疾高风险期每月对5岁以下儿童给予治疗剂量的药物。当前的SMC指南建议对未感染和无症状恶性疟原虫感染的儿童给予相同的治疗。然而，一个关键的知识空白仍然是无症状感染对SMC在预防四周内临床疟疾疗效的影响。本研究旨在评估SMC治疗期间临床疟疾的风险及其与儿童感染状况的关联。
本研究在马里的库利科罗健康区进行，重点关注10岁以下儿童。2019年共随机选取726名儿童，2020年共随机选取1452名儿童，并在整个SMC活动期间进行跟踪。在每次SMC药物给药前，通过显微镜检查评估每轮无症状恶性疟原虫感染的患病率。对儿童进行为期四周的被动监测，以记录临床疟疾的发病率。使用R-Studio软件进行数据分析。通过逻辑回归分析估计基于感染状况的临床疟疾风险，并使用Kaplan-Meier曲线比较感染儿童和未感染儿童的生存时间。使用Pearson卡方检验比较比例，统计学显著性设定为p < 0.05。
在整个研究年份中，无症状恶性疟原虫感染的平均患病率为11.0%。2019年（p < 0.001）和2020年（p = 0.016）5至9岁儿童的患病率明显更高。在两个传播季节中，无症状感染儿童患临床疟疾的风险显著更高：2019年：（RR = 3.05，CI [2.04 - 4.72]）和2020年（RR = 1.43，CI [1.04 - 1.97]）。此外，在这两年中，感染儿童首次出现疟疾发作的时间明显更短（2019年p < 凭，2020年p = 0.01）。
这些发现表明，在实施SMC期间，无症状感染儿童患临床疟疾的风险升高。在进行SMC给药前筛查和治疗恶性疟原虫感染，可大幅提高该策略在降低流行地区疟疾发病率方面的有效性。
