近日，美国疾病控制和预防中心寄生虫病和疟疾司John E Gimnig团队近日取得一项新成果。他们分析了一种空间驱虫产品对疟疾发病率的影响，并于2024年12月19日发表在《柳叶刀》杂志上。

空间驱虫产品用于预防昆虫叮咬，空间驱避的昆虫学效果有大量证据。作为一种新的病媒控制选择，空间驱蚊产品旨在将活性成分释放到空气中，以中断人与病媒的接触，从而减少人类接触蚊媒病原体。临床试验表明，空间驱虫剂对伊蚊传播的病毒具有流行病学疗效，但对疟疾的疗效尚无定论。该研究旨在肯尼亚布西亚县展示和量化空间驱虫剂在降低疟疾感染率方面的保护功效。

研究组在肯尼亚西部布西亚县进行了一项前瞻性、集群随机、对照试验，以量化在大规模分发驱虫蚊帐后，基于四氟苯菊酯的空间驱虫剂对人类疟疾感染的疗效。研究人员、工作人员和研究参与者对集群分配双盲。在4个月的基线（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）内，通过显微镜测量6个月至10岁以下儿童的感染率。从58个群组（29个干预组，29个安慰剂组）中，分别通过中期和试验结束时间点的生存分析，对来自两个连续12个月队列的1526名和1546名参与者进行了首次疟疾感染（主要终点）评估。

主要终点的结果表明，空间驱虫剂显著降低了33.4%的首次疟疾感染风险（95%CI 11.1-50.1；p=0.0058）和32.1%的新发疟疾感染风险（15.9-45.2；p=0.0004）。尚无报告的不良事件和严重不良事件被认为与空间驱虫剂有关。

试验提供了首个证据，证明在以高疟疾传播率、对拟除虫菊酯有抗性的疟疾媒介和杀虫剂处理过的蚊帐覆盖率高为特征的非洲环境中，空间驱虫保护功效在降低疟疾感染风险方面具有示范性。研究结果支持空间驱蚊产品是预防疟疾的有益组成部分。

附：英文原文

Title: Effect of a spatial repellent on malaria incidence in an area of western Kenya characterised by high malaria transmission, insecticide resistance, and universal coverage of insecticide treated nets (part of the AEGIS Consortium): a cluster-randomised, controlled trial

Author: Eric O Ochomo, John E Gimnig, Quentin Awori, Bernard Abongo, Prisca Oria, Nickline K Ashitiba, Brian Polo, Vincent Moshi, Hilda Otanga, Ferdinard Adungo, Eunice A Ouma, Susan Outa, Edith Ramaita, Rebecca Levine, Wycliffe Odongo, Steven A Harvey, April Monroe, Ashley Hudson, Bradley Sandberg, Jared Hendrickson, Xingyuan Zhao, Ruyu Zhou, Fang Liu, Nicole L Achee, John P Grieco

Issue&Volume: 2024-12-19

Abstract:

Background

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.

Methods

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.

Findings

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.

Interpretation

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.

DOI: 10.1016/S0140-6736(24)02253-0

Source: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(24)02253-0/abstract