Ochomo Eric O, Gimnig John E, Awori Quentin, Abong'o Bernard, Oria Prisca, Ashitiba Nickline K, Polo Brian, Moshi Vincent, Otanga Hilda, Adung'o Ferdinard, Ouma Eunice A, Outa Susan, Ramaita Edith, Levine Rebecca, Odongo Wycliffe, Harvey Steven A, Monroe April, Hudson Ashley, Sandberg Bradley, Hendrickson Jared, Zhao Xingyuan, Zhou Ruyu, Liu Fang, Achee Nicole L, Grieco John P
Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya; Vector Group, Liverpool School of Tropical Medicine, Liverpool, UK.
Centers for Disease Control and Prevention, Division of Parasitic Diseases and Malaria, Atlanta, GA, USA.
Lancet. 2025 Jan 11;405(10473):147-156. doi: 10.1016/S0140-6736(24)02253-0. Epub 2024 Dec 19.
Spatial repellent products are used for prevention of insect bites, and a body of evidence exists on spatial repellent entomological efficacy. A new option for vector control, spatial repellent products are designed to release active ingredient into the air for disruption of human-vector contact thereby reducing human exposure to mosquito-borne pathogens. Clinical trials have shown spatial repellent epidemiological efficacy against Aedes-borne viruses but inconclusive outcomes against malaria. We aimed to show and quantify the protective efficacy of spatial repellents in reducing malaria infection incidence in Busia County, Kenya.
A prospective, cluster-randomised, controlled trial in Busia County, western Kenya was done to quantify the efficacy of a transfluthrin-based spatial repellent against human malaria infection following mass distribution of insecticide treated nets. Investigators, staff, and study participants were masked to cluster allocation. Infection incidence was measured by microscopy in children aged 6 months to younger than 10 years during a 4-month baseline (March-July 2021) and 24-month follow-up period with intervention (October, 2021-October, 2023). From 58 clusters (29 intervention, 29 placebo), a total of 1526 and 1546 participants from two consecutive, 12-month cohorts were assessed for first-time malaria infection (primary endpoint) by survival analysis at interim and end-of-trial timepoints, respectively. This trial is registered with ClinicalTrials.gov, NCT04766879 and is complete.
The outcome of the primary endpoint indicated that spatial repellents significantly reduced the hazard rate of first-time malaria infection by 33·4% (95% CI 11·1-50·1; p=0·0058) and the hazard rate of overall new malaria infections by 32·1% (15·9-45·2; p=0·0004). No reported adverse events and serious adverse events were deemed to be associated with the spatial repellent.
Our trial provides the first evidence of a demonstrative spatial repellent protective efficacy in reducing risk of malaria infection in an African setting characterised by high malaria transmission, pyrethroid resistant malaria vectors, and high coverage of insecticide treated nets. Results support spatial repellent products as a beneficial component of malaria prevention.
This study was funded by Unitaid to the University of Notre Dame.
空间驱避产品用于预防蚊虫叮咬，关于其昆虫学驱避效果已有大量证据。作为病媒控制的一种新选择，空间驱避产品旨在将活性成分释放到空气中，以阻断人与病媒的接触，从而减少人类接触蚊媒传播病原体的机会。临床试验表明，空间驱避产品对伊蚊传播的病毒具有流行病学预防效果，但对疟疾的预防效果尚无定论。我们旨在证明并量化空间驱避剂在肯尼亚布西亚县降低疟疾感染发病率方面的保护效果。
在肯尼亚西部的布西亚县开展了一项前瞻性、整群随机对照试验，以量化在大规模分发经杀虫剂处理的蚊帐后，基于甲氧苄氟菊酯的空间驱避剂对人类疟疾感染的预防效果。研究人员、工作人员和研究参与者均不知道整群分配情况。在为期4个月的基线期（2021年3月至7月）和24个月的干预随访期（2021年10月至2023年10月），通过显微镜检查测量6个月至未满10岁儿童的感染发病率。在58个群组（29个干预组，29个安慰剂组）中，分别在中期和试验结束时，通过生存分析对来自两个连续12个月队列的总共1526名和1546名参与者进行首次疟疾感染（主要终点）评估。该试验已在ClinicalTrials.gov注册，注册号为NCT04766879，现已完成。
主要终点结果表明，空间驱避剂使首次疟疾感染的风险率显著降低了33.4%（95%置信区间11.1 - 50.1；p = 0.0058），使总体新疟疾感染的风险率降低了32.1%（15.9 - 45.2；p = 0.0004）。未报告与空间驱避剂相关的不良事件和严重不良事件。
我们的试验首次证明了在疟疾传播率高、对拟除虫菊酯耐药的疟疾媒介以及经杀虫剂处理蚊帐覆盖率高的非洲环境中，空间驱避剂在降低疟疾感染风险方面具有显著的保护效果。研究结果支持空间驱避产品作为疟疾预防的有益组成部分。
本研究由国际药品采购机制资助，资金提供给圣母大学。
