Noor Abdisalan Mohamed, Kibuchi Eliud, Mitto Bernard, Coulibaly Drissa, Doumbo Ogobara K, Snow Robert W
INFORM (Information for Malaria - www.inform-malaria.org), Spatial Health Metrics Group, Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya; Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom.
INFORM (Information for Malaria - www.inform-malaria.org), Spatial Health Metrics Group, Kenya Medical Research Institute/Wellcome Trust Research Programme, Nairobi, Kenya.
PLoS One. 2015 Aug 31;10(8):e0136919. doi: 10.1371/journal.pone.0136919. eCollection 2015.
Seasonal malaria chemoprevention (SMC) has been shown to be highly efficacious against clinical malaria in areas where transmission is acutely seasonal. SMC targeting depends on a complex interplay of climate, malaria transmission and population distribution. In this study a spatial decision support framework was developed to identify health districts suitable for the targeting of SMC across seven Sahelian countries and northern states of Nigeria that are members of the Nouakchott Initiative.
A spatially explicit decision support framework that links information on seasonality, age-structured population, urbanization, malaria endemicity and the length of transmission season was developed to inform SMC targeting in health districts. Thresholds of seasonality, population and receptive risks were defined to delineate SMC suitable health districts and define the age range of children for targeting. Numbers of children were then computed for the period 2015-2020 in SMC districts. For 2015, this was combined with maps of length of malaria transmission seasons and WHO recommended treatment regimen to quantify the number of tablets required across the SMC health districts.
A total of 597 Sahelian health districts were mapped, out of which 478 (80.1%) were considered suitable for SMC based on seasonality and endemicity thresholds. These districts had an estimated 119.8 million (85%) of the total population in 2015. In the six years from 2015-2020, it is estimated that a total of 158 million children 3m to <5 years, 121 million of whom were in rural areas, will need SMC to achieve universal coverage in the Sahel. If the upper age limit of SMC targeted children was increased to <10 years in low transmission districts, a total 177 million overall, of whom 135 million were rural children, will require chemoprevention in 2015-2020. In 2015 alone, an estimated 49-72 million SP tablets and 148-217 million AQ tablets will be needed to cover all or rural children respectively under the different scenarios of upper age limits.
Our proposed framework provides a standardised approach to support targeting and scale up of SMC by the countries of the Nouakchott Initiative. Our analysis suggests that the vast majority of the population in this region are likely to benefit from SMC and substantial resources will be required to reach universal coverage each year.
在疟疾传播呈急性季节性的地区，季节性疟疾化学预防（SMC）已被证明对临床疟疾具有高效性。SMC的目标定位取决于气候、疟疾传播和人口分布之间的复杂相互作用。在本研究中，开发了一个空间决策支持框架，以确定适合在参与努瓦克肖特倡议的七个萨赫勒国家和尼日利亚北部各州开展SMC的卫生区。
开发了一个空间明确的决策支持框架，该框架将季节性、年龄结构人口、城市化、疟疾流行程度和传播季节长度等信息联系起来，为卫生区的SMC目标定位提供依据。定义了季节性、人口和易感风险的阈值，以划定适合开展SMC的卫生区，并确定目标儿童的年龄范围。然后计算了2015 - 2020年期间SMC地区的儿童数量。对于2015年，将其与疟疾传播季节长度图和世界卫生组织推荐的治疗方案相结合，以量化SMC卫生区所需的药片数量。
共绘制了597个萨赫勒卫生区的地图，其中478个（80.1%）基于季节性和流行程度阈值被认为适合开展SMC。这些地区在2015年估计占总人口的1.198亿（85%）。从2015年到2020年的六年中，估计共有1.58亿3个月至不满5岁的儿童需要SMC，以在萨赫勒地区实现普遍覆盖，其中1.21亿在农村地区。如果在低传播地区将SMC目标儿童的年龄上限提高到不满10岁，那么在2015 - 2020年期间总共将有1.77亿儿童需要化学预防，其中1.35亿是农村儿童。仅在2015年，在不同年龄上限的情况下，估计分别需要4900 - 7200万片磺胺多辛 - 乙胺嘧啶（SP）药片和1.48 - 2.17亿片青蒿琥酯 - 阿莫地喹（AQ）药片来覆盖所有儿童或农村儿童。
我们提出的框架提供了一种标准化方法来支持努瓦克肖特倡议国家开展SMC的目标定位和扩大规模。我们的分析表明，该地区绝大多数人口可能从SMC中受益，并且每年需要大量资源才能实现普遍覆盖。
