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Table 1 Summary of cluster-randomised trial and non-randomised cluster intervention studies evaluating the effect of WASH interventions on soil-transmitted helminth infections

From: The role of water, sanitation and hygiene interventions in reducing soil-transmitted helminths: interpreting the evidence and identifying next steps

Setting Design Follow-up duration Intervention and control STH outcomes Impact on STH
School-based trials
 Peru, Belén [11] Pair-matched cluster-randomized controlled trial in 18 schools 4 months Intervention: deworming followed by hygiene education which was supported by fortnightly support visits
Control: deworming alone
STH infection; knowledge about STH among grade 5 school children (~12 years of age) Intensity of A. lumbricoides 58% lower in the intervention arm but no impact on intensity of T. trichiura or hookworm; no impact on prevalence of any STH
 China, Hunan Province [10] Single-blind, unmatched, cluster-randomized trial in 38 urban schools 1 school year Intervention: Behavior change intervention, including a cartoon video
Control: display of a health-education poster
A. lumbricoides and T. trichiura infection; knowledge about STH; hand-washing behavior (hookworm not present) 50% reduction in STH infection
 Kenya, Nyanza Province [12] Cluster-randomized trial in 40 schools 10 months Intervention: deworming followed by hygiene promotion, water treatment technology and supplies, latrine construction and hand washing and drinking water storage containers
Control: deworming alone
STH reinfection among school children 44% reduction on A. lumbricoides reinfection, but no impact on other STH species
Community-based trials
 Northern Ethiopia [24] Individual 2 × 2 factorial clustered randomized in 216 households 6 months Intervention: promotion of handwashing with (provided) soap and nail clipping STH reinfection among children aged 6–15 years Lower rates of STH reinfection among children receiving handwashing intervention (14 vs 29%) and nail clipping (17 vs 26%)
 India, Odisha [13] Cluster-randomized trial in 100 rural villages 30 months Intervention: latrine promotion and construction, as part of a CLTS campaign STH infection among children aged <5 years No impact on STH infection
 India, Madhya Pradesh [14] Cluster-randomized trial in 80 rural villages 21 months Intervention: subsidies for and promotion of household latrines, as part of a CLTS campaign STH infection among children aged <2 years No impact on STH infection
 Kenya, Western Province [16] Cluster-randomized trial in 1226 villages grouped into 702 clusters 24 months Intervention: 6 interventions including water, sanitation, handwashing, nutrition, combined WASH, and combined WASH plus nutrition (WSHN)
Control: active and passive controls (no deworming)
STH infection among children aged 2 years and an older child in each household (mainly A. lumbricoides) A. lumbricoides infection prevalence was 18% lower in the water arm, 22% lower in the combined WASH arm, and 22% lower in the WSHN arm
 Bangladesh [17] Cluster-randomized trial in 5551 compounds grouped into 702 clusters 26 months Intervention: 6 interventions including water, sanitation, handwashing, nutrition, combined WASH, and combined WASH plus nutrition (WSHN)
Control: passive controls (no deworming by study)
STH infection among children aged 2 years and up to 2 older children in each household Water intervention reduced hookworm by 31% but did not affect other STH. Sanitation reduced T. trichiura by 29%, had a similar borderline effect on hookworm and no effect on A. lumbricoides. Combined WASH reduced hookworm by 29% and WSHN by 33%
 Timor-Leste, Manufahi [19] Cluster-randomized trial in 18 rural villages 24 months after 1st deworming Intervention: provision of water, CLTS based sanitation promotion and handwashing education, integrated with deworming of whole communities
Control: deworming of whole communities
STH infection among entire communities No additional impact of WASH interventions on STH infection compared to deworming alone
Non-randomised studies
 Côte d’Ivoire, south-eastern [20] Non-randomized cluster intervention study in 9 villages 13 months Intervention: CTS campaign and hygiene education plus two rounds of community-based deworming
Control: two rounds of community-based deworming
STH infection among household members (mainly hookworm present) No statistically significant impact on STH prevalence, potentially higher hookworm ERR in intervention
  1. Abbreviations: CLTS, community-led total sanitation; ERR: egg reduction rate; STH: soil-transmitted helminth