Volatile pyrethroid spatial repellents for preventing mosquito bites: a systematic review and meta-analysis

Authors: CHEN, INGRID - University Of California San Francisco (UCSF); MILLER, SARAH - University Of California San Francisco (UCSF); MSELLEMU, DANIEL - Ifakara Health Institute; LUGENGE, AIDI - Ifakara Health Institute; SWAI, JOHSON - Ifakara Health Institute; ACHEE, NICOLE - University Of Notre Dame; ANDRES, MARTA - University College London; BIBBS, CHRIS - Salt Lake City Mosquito Abatement District; BURTON, TIMOTHY - University Of Notre Dame; CHAREONVIRIYAPHAP, THEERAPHAP - Kasetsart University; DEBBOUN, MUSTAPHA - Delta Mosquito And Vector Control District; DEVINE, GREG - Qimr Berghofer Medical Research Institute; ELMAN, NOEL - Gearjump Technologies, Llc; FILLINGER, ULRIKE - International Centre Of Insect Physiology And Ecology; FLORES-MENDOZA, CARMEN - Us Army Medical Research Institute; Gibson, Seth; GOVELLA, NICODEM - Ifakara Health Institute; GOWELO, STEVEN - University Of California San Francisco (UCSF); HORSTMANN, SEBASTIAN - Bayer Cropscience; KAWADA, HITOSHI - Nagasaki University; KILLEEN, GERRY - University College Cork; Kline, Daniel; LLOYD, AARON - Lee County Mosquito District; LOBO, NEIL - University Of Notre Dame; MAIA, MARTA - Kemri Wellcome Trust Research Programme; MCPHATTER, LEE - Us Army Medical Research Institute; MMBANDO, ARNOLD - Ifakara Health Institute; MORRISON, AMY - University Of Notre Dame; MPONZI, WINIFRIDA - Ifakara Health Institute; MWANGA, EMMANUEL - Ifakara Health Institute; NJOROGE, MARGARET - International Centre Of Insect Physiology And Ecology; OGOMA, SHEILA - Swiss Tropical Institute(STI); OKUMU, FREDROS - Ifakara Health Institute; OPIYO, MERCY - University Of California San Francisco (UCSF); PALIGA, JOHN - Ifakara Health Institute; PONGSIRI, ARISSARA - Armed Forces Research Institute Of Medical Sciences; PONLAWAT, ALONGKOT - Armed Forces Research Institute Of Medical Sciences; SAEAUNG, MANOP - Kasetsart University; SALAZAR, FERDINAND - Research Institute For Tropical Medicine; SANGORO, ONYANGO - International Centre Of Insect Physiology And Ecology; STEVENSON, JENNY - Johns Hopkins University; SUKKANON, CHUTIPONG - Mahidol University; SYAFRUDDIN, DIN - University Of Notre Dame; TAMBWE, MGENI - Ifakara Health Institute; TANGENA, JULIE - Liverpool School Of Tropical Medicine; VAJDA, ELODIE - University Of California San Francisco (UCSF); VAZQUEZ-PROKOPEC, GONZALO - Emory University; WAGMAN, JOSEPH - Path; YAN, CHANLY - Kasetsart University; ALLEN, ISABELLE - University Of California San Francisco (UCSF); MOORE, SARAH - Ifakara Health Institute; TANGENA, JULIE - Liverpool School Of Tropical Medicine; MORENO-GÓMEZ, MARA - Henkel Corporation; OUMBOUKE, WELBECK - (NCE, CECR)networks Of Centres Of Exellence Of Canada, Centres Of Excellence For Commercilization A

Submitted to: EBioMedicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/2025
Publication Date: 8/26/2025
Citation: Chen, I., Miller, S.L., Msellemu, D., Lugenge, A., Swai, J.K., Achee, N., Andres, M., Bibbs, C., Burton, T., Chareonviriyaphap, T., Debboun, M., Devine, G., Elman, N., Fillinger, U., Flores-Mendoza, C., Gibson, S., Govella, N., Gowelo, S., Horstmann, S., Kawada, H., Killeen, G., Kline, D.L., Lloyd, A., Lobo, N.F., Maia, M., Mcphatter, L., Mmbando, A., Morrison, A., Mponzi, W., Mwanga, E., Njoroge, M., Ogoma, S., Okumu, F., Opiyo, M., Paliga, J., Pongsiri, A., Ponlawat, A., Saeaung, M., Salazar, F., Sangoro, O., Stevenson, J., Sukkanon, C., Syafruddin, D., Tambwe, M., Tangena, J., Vajda, E., Vazquez-Prokopec, G., Wagman, J., Yan, C., Allen, I.E., Moore, S.J., Tangena, J., Moreno-Gómez, M., Oumbouke, W. 2025. Volatile pyrethroid spatial repellents for preventing mosquito bites: a systematic review and meta-analysis. EBioMedicine. 105891. https://doi.org/10.1016/j.ebiom.2025.105891.
DOI: https://doi.org/10.1016/j.ebiom.2025.105891

Interpretive Summary: Spatial repellents are a new kind of repellent that does not need to be put on the skin, but instead can be dispersed from a device or fabric treatment to prevent mosquito-borne diseases. Unfortunately there is no standard method to evaluate spatial repellents, with resultant lack of clarity on their level of protection against mosquito bites. In this systematic review and meta-analysis we consolidate the evidence base on spatial repellent protective efficacy against several high-threat mosquito species and test methods used. From our review of 61 studies we found that spatial repellents offered an average 56% protection against mosquito bites and we found that efficacy was not sensitive to temperature, humidity, or wind. Importantly, we found that testing spatial repellents by direct observation of how many mosquitoes landed on a person to bite them is superior to indirect studies where mosquitoes are counted in traps. We conclude that spatial repellents can protect people from mosquito bites, and that efficacy can vary by the species of mosquito. Future work should incorporate studies with direct observation of mosquito landing on humans, and should be conducted in the field instead of controlled laboratory or semi-field conditions, especially in West African and South American settings.

Technical Abstract: Background: volatile pyrethroid spatial repellents (VPSRs) can prevent mosquito-borne diseases. The use of heterogeneous methods to evaluate VPSRs have resulted in a lack of clarity on their measure of protection against mosquito bites. This systematic review and meta-analysis consolidates the evidence base on VPSR protective efficacy against Anopheles, Aedes, and Culex mosquitoes and test methods used. Methods: We identified articles published between January 2000 and September 2023 by searching through published literature and unpublished sources. We included semi-field or field studies that measured the efficacy of VPSRs using human landing catch and/or mosquito trap density, summarizing data at a study level using a generalized linear mixed model with random effects. Original study data were also obtained, pooled, and 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. PROSPERO registration: CRD42021268852. Findings: 61 eligible studies showed that VPSRs offered an average 56% (95% CI 50, 62%) protection against mosquito bites. Of these studies, original data from 50 were obtained and pooled in a meta-analysis involving 1,703,120 mosquitoes, showing that protective efficacy was highest using human landing catch (HLC) (67% efficacy, 95% CI 64, 69%), similar when using semi-field (58%, 95% CI 54, 62%) vs field studies (50%, 95% CI 40, 58%), highest in Anopheles arabiensis (75%, 95% CI 72, 78%), and lowest in Anopheles funestus (31%, 95% CI 18, 42%); the potential for cross-resistance to solid-state pyrethroids is unclear. Efficacy was not sensitive to temperature, humidity, or wind. Interpretation: VPSRs offer protection from mosquito bites, with semi-field studies reflecting field data. Future studies should evaluate VPSR by HLC if possible. More field studies to evaluate protection outdoors are needed, especially in West African and South American settings.