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.

Ochomo, Eric, 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 and Grieco, John P (2024) '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.'. The Lancet, Vol 405, Issue 10473, pp. 147-156.

Text Effect of a spatial repellent on malaria incidence in an area of western Kenya.pdf - Accepted Version Restricted to Registered users only until 19 May 2025. Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (901kB)

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.

Item Type:	Article
Subjects:	QW Microbiology and Immunology > Viruses > QW 162 Insect viruses QX Parasitology > Insects. Other Parasites > QX 510 Mosquitoes WC Communicable Diseases > Tropical and Parasitic Diseases > WC 750 Malaria
Faculty: Department:	Biological Sciences > Vector Biology Department
Digital Object Identifer (DOI):	https://doi.org/10.1016/S0140-6736(24)02253-0
SWORD Depositor:	JISC Pubrouter
Depositing User:	JISC Pubrouter
Date Deposited:	05 Mar 2025 12:34
Last Modified:	05 Mar 2025 12:34
URI:	https://archive.lstmed.ac.uk/id/eprint/25946

Statistics

View details

Actions (login required)

Edit Item