LASR · Effect of long-acting spatial repellents (LASR) vs indoor residual spraying (IRS) on malaria burden in western Kenya: a cluster-randomised trial

Evidence of the impact of long-acting spatial repellents (LASR) on malaria burden is urgently needed. We propose to conduct a rigorous, cluster-randomised trial to evaluate the effectiveness of LASR and indoor residual spraying (IRS) in Kenya. The trial will include 66 clusters (villages) in western Kenya where malaria transmission is intense. The clusters will be randomised to one of three study arms including: (1) LASR (intervention #1) with SC Johnson’s Guardian™ product, (2) IRS with pirimiphos-methyl (intervention #2), and (3) standard control (no intervention). All clusters will receive standard malaria control interventions, including long-lasting insecticidal nets (LLINs) distributed by the Kenyan National Malaria Control Program and malaria vaccines (as and when these are deployed). The evaluation will include repeated cross-sectional community surveys (conducted at baseline and then every 6 months for 2 years) to gather information on household characteristics and parasite prevalence in children aged 2-10 years, malaria incidence as captured through health facility surveillance, entomological surveillance, mosquito behaviour studies and insecticide resistance monitoring, qualitative research to explore barriers to delivering LASR and IRS, and an economic evaluation. The primary objective of the study is to evaluate the impact of LASR (Guardian™) as compared to standard control on parasite prevalence in western Kenya. We will test the hypothesis that parasite prevalence as measured in cross-sectional surveys will be lower in intervention clusters (villages randomised to receive LASR), than in control clusters (villages randomised to standard control). The field work in Kenya will be led by the Kenya Medical Research Institute (KEMRI), coordinated by the Liverpool School of Tropical Medicine (LSTM), and supported by Radboud University Medical Centre, Netherlands, the Institute of Tropical Medicine, Belgium, and the US Centers of Disease Control.""