Journal Article

Community evaluation of VECTRON™ T500 (broflanilide) for indoor residual spraying for malaria vector control in Siaya county, Kenya

Ramaita, Edith, Muchoki, Margaret, Polo, Brian, Kipsum, Mathew, Sang, David, Ochomo, Eric, Bange, Teresa, Kiptoo, Paul, Mburugu, Patrick, Wekesa, Celestine N., Abong’o, Bernard, Machani, Maxwell G., Abbey, Ismael, Omondi, Seline, Keitany, Kibor

2025

Overview

Background Indoor residual spraying (IRS) remains a core malaria vector control intervention, but widespread insecticide resistance threatens its effectiveness. VECTRON™ T500, containing broflanilide, represents a novel IRS product with a new mode of action targeting GABA receptors. Methods A two-arm non-inferiority study was conducted in Bar Olengo, Siaya County, Kenya, between June and November 2024. Twenty-five structures per arm were sprayed with either VECTRON™ T500 (100 mg a.i/m 2 ) or Actellic™ 300CS (1 g a.i/m 2 ), with five water-sprayed controls. Residual efficacy was assessed using world health organization (WHO) cone bioassays with pyrethroid-resistant Anopheles gambiae sensu stricto ( s.s .) Bungoma strain and susceptible Kisumu strain monthly for six months. Wild vector susceptibility to insecticides, community acceptability, and adverse events were evaluated. Results VECTRON™ T500 maintained significantly higher mortality than Actellic™ 300CS throughout six months on both wall types. Against resistant An. gambiae s.s. Bungoma strain, VECTRON™ T500 achieved 98.73 ± 3.51% mortality (95% CI 97.95–99.51%) compared to 80.22 ± 11.23% for Actellic™ 300CS (95% CI 77.72–82.72%; t₇₈ = − 10.15, p < 0.001, Cohen's d = 2.27). For susceptible Kisumu strain, VECTRON™ T500 maintained 100% mortality versus 89.60 ± 6.34% for Actellic™ 300CS (95% CI 88.19–91.01%; t₇₈ = 10.53, p < 0.001, Cohen's d = 2.38). Actellic™ 300CS efficacy declined below 80% after month 4, while VECTRON™ T500 remained > 95% effective throughout. Wild An. gambiae sensu lato ( s.l .) and Anopheles funestus s.l. showed 100% susceptibility to broflanilide with no cross-resistance detected. No adverse events occurred in VECTRON™ T500 households versus 8% (12/150) in Actellic™ 300CS households. Community acceptance was 100% for VECTRON™ T500 versus 99.33% (149/150) for Actellic™ 300CS, though this difference was not statistically significant. Conclusions VECTRON™ T500 demonstrated superior residual efficacy, excellent safety profile, and high community acceptance compared to Actellic™ 300CS. Its novel mode of action and absence of cross-resistance to pirimiphos-methyl and pyrethroids make it valuable for insecticide resistance management in malaria vector control programmes.

• Publisher: BioMed Central,BioMed Central Ltd,BMC
• Subject: Animals / Anopheles - drug effects / Anopheles gambiae / Biomedical and Life Sciences / Biomedicine / Broflanilide / Control / Entomology / Evaluation / Female / Humans / Indoor residual spraying / Infectious Diseases / Insecticide Resistance / Insecticides - pharmacology / Kenya / Malaria / Malaria - prevention & control / Malaria vector control / Methods / Microbiology / Mosquito Control - methods / Mosquito Vectors - drug effects / Parasitology / Public Health / Tropical Medicine / Vector control