Volatile pyrethroid spatial repellents for preventing mosquito bites: a systematic review and meta-analysis
Year: 2025
Type: review
Study designs: Systematic Review, Meta-Analysis
Abstract: BACKGROUND: Volatile pyrethroid spatial repellents (VPSRs) can prevent mosquito-borne diseases including malaria and dengue fever, but the use of varied evaluation methods has resulted in a lack of clarity regarding their protective efficacy (PE) against contact with mosquitoes. This systematic review and meta-analysis consolidates the entomological evidence base on the PE of VPSRs against Anopheles, Aedes, and Culex mosquitoes and different test methods used. METHODS: We identified studies completed between January 2000 and September 2023 by searching through databases, conference abstracts, and personal correspondences. Included studies were semi-field or field studies that measured the PE of VPSRs using human landing catch (HLC) of mosquito landings on human legs and/or mosquito trap density, the number of mosquitoes captured using traps per set time period, compared to control groups. The systematic review summarised study-level data using a generalised linear mixed model with random effects. The meta-analysis pooled individual mosquito-level data and weather data on temperature, humidity, and wind from satellites, analysing PE subgrouped by product format, active ingredient, mosquito capture method used, mosquito species, and indoor vs outdoor setting. Risk of bias was assessed using a SYRCLE tool adapted for mosquito studies. Additional studies published from October 2023 to July 2025 were summarised. PROSPERO registration: CRD42021268852. FINDINGS: 58 eligible publications showed that VPSRs provided an average of 56% (95% CI 50, 62%) PE from mosquito bites. Meta-analysis of individual mosquito-level data from 50 (86%) of eligible studies involving 1,703,120 mosquitoes showed that PE was highest when measured using HLC, with similar results seen in semi-field (58%, 95% CI 54, 62%) and field studies (50%, 95% CI 40, 59%). Differences between indoor (54%, 95% CI 18, 68%) and outdoor settings (56%, 95% CI 51, 60%) were unclear. Species-level differences were observed with low PE seen in Anopheles funestus (31%, 95% CI 19, 43%); the potential for cross-resistance to solid-state pyrethroids is unclear. Efficacy was not sensitive to combined weather effects. INTERPRETATION: VPSRs offer protection from contact with mosquitoes, with semi-field studies reflecting field data and species-level differences observed. HLC provided the best quality data. Additional field studies that evaluate outdoor protection in malaria-endemic settings are needed, especially in West African, South American, and Southeast Asian settings. FUNDING: National Institutes of Health (National Institute of Allergy and Infectious Diseases (K01AI156182)) and "Accelerate to Eliminate Malaria" program.
Source: EBioMedicine
Authors: Ingrid Chen, Sarah L. Miller, Daniel Msellemu, Aidi G. Lugenge, Johnson Kyeba Swai, Nicole Achee, Marta Andrés, Christopher S. Bibbs, Theeraphap Chareonviriyaphap, J. Derek Charlwood, Greg Devine, Noel Elman, Ulrike Fillinger, Carmen Flores-Mendoza, Seth Gibson, Nicodem Govella, Steven Gowelo, Sebastian Horstmann, Hitoshi Kawada, Daniel Kline, Aaron Lloyd, Neil F. Lobo, Marta F. Maia, Arnold Mmbando, Mara Moreno-Gómez, Amy C. Morrison, Winifrida Mponzi, Emmanuel P. Mwanga, Margaret Njoroge, Sheila B. Ogoma, Fredros O. Okumu, Mercy Opiyo, Welbeck A. Oumbouke, John Paliga, Arissara Pongsiri, Alongkot Ponlawat, Manop Saeaung, Ferdinand Salazar, Onyango Sangoro, Jennifer C. Stevenson, Chutipong Sukkanon, Din Syafruddin, Mgeni Mohamed Tambwe, Julie-Anne A. Tangena, Elodie A. Vajda, Gonzalo Vazquez-Prokopec, Joseph M. Wagman, Chanly Yan, Isabel Elaine Allen, Sarah J. Moore
Institutions: University of California, San Francisco, Ifakara Health Institute, University of Notre Dame, Consejo Superior de Investigaciones Científicas, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, University College London, Kasetsart University, Universidade Nova de Lisboa, QIMR Berghofer Medical Research Institute, United States Naval Medical Research Unit SOUTH, Agricultural Research Service, Center for Medical, Agricultural and Veterinary Entomology, Nagasaki University, Institute of Tropical Medicine, Nagasaki University, Kenya Medical Research Institute, University of Oxford, KEMRI-Wellcome Trust Research Programme, Durham University, University of California, Davis, International Centre of Insect Physiology and Ecology, Abt Global (United States), University of Glasgow, Liverpool School of Tropical Medicine, Department of Health, Research Institute for Tropical Medicine, Mahidol University, Hasanuddin University, Swiss Tropical and Public Health Institute, Emory University
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $5,780
OpenAlex ID: W4413970877