Are there synergies from combining hygiene and sanitation promotion campaigns: Evidence from a large-scale cluster-randomized trial in rural Tanzania

Abstract

SummaryThe current evidence on handwashing and sanitation programs suggests limited impacts on health when at-scale interventions have been tested in isolation. However, no published experimental evidence currently exists that tests the interaction effects between sanitation and handwashing. We present the results of two large-scale, government-led handwashing and sanitation promotion campaigns in rural Tanzania, with the objective of tracing the causal chain from hygiene and sanitation promotion to changes in child health outcomes and specifically testing for potential interaction effects of combining handwashing and sanitation interventions.MethodsThe study is a factorial cluster-randomized control trial where 181 rural wards from 10 districts in Tanzania were randomly assigned to receive sanitation promotion, handwashing promotion, both interventions together or neither (control). Interventions were rolled out from February 2009 to June 2011 and the endline survey was conducted from May to November 2012, approximately one year after program completion. The sample was composed of households with children under 5 years old in the two largest villages in each ward. Masking was not possible due to the nature of the intervention, but enumerators played no part in the intervention and were blinded to treatment status. The primary outcome of interest was 7-day diarrhea prevalence for children under five. Intermediate outcomes of behavior change including improved latrine construction, levels of open defecation and handwashing with soap were also analyzed. Secondary health outcomes included anemia, height-for-age and weight-for-age of children under 5. An intention-to-treat analysis was used to assess the relationship between the interventions and outcomes of interest.FindingsOne year after the end of the program, ownership of improved latrines increased from 49.7% to 64.8% (95% CI 57.9%-71.7%) and regular open defecation decreased from 23.1% to 11.1% (95% CI 3.5%-18.7%) in sanitation promotion-only wards. Households in handwashing promotion-only wards showed marginal improvements in handwashing behavior related to food preparation but not at other critical junctures. There were no detectable interaction effects for the combined intervention. The associated cost-per-household gaining access to improved sanitation is estimated to be USD $194. Final effects on child health measured through diarrhea, anemia, stunting and wasting were absent in all treatment groups.InterpretationAlthough statistically significant, the changes in intermediate outcomes achieved through each intervention in isolation were not large enough to generate meaningful health impacts. With no observable signs of interaction, the combined intervention produced similar results. The study highlights the importance of focusing on intermediate outcomes of take up and behavior change as a critical first step in large-scale programs before realizing the changes in health that sanitation and hygiene interventions aim to deliver.Trial registrationClinicaltri...

Can individual and integrated water, sanitation, and handwashing interventions reduce fecal contamination in the household environment? Evidence from the WASH Benefits cluster-randomized trial in rural Kenya

“…We found no evidence that combining water, sanitation, and hygiene interventions led to larger reductions in fecal contamination in the household environment than single interventions, a finding consistent with no additive benefit on health outcomes measured in this trial or in other studies. 15, [36][37][38][39][40] Our results indicate that the intensive WSH interventions implemented in this study did not reduce levels of fecal indicator bacteria on child hands or toys, while they slightly reduced fly presence near latrines and marginally improved visible hand cleanliness of caregivers. The lack of effect on fecal indicator bacteria measured on hands and toys has several possible explanations, including inconsistent compliance of the targeted hygiene and sanitation behaviors, failure of these specific types of WSH interventions to reduce human fecal contamination on child hands and toys, or animal fecal contamination in the household environment.…”

A systematic review of hand-hygiene and environmental-disinfection interventions in settings with children

“…Prior to collecting data, a power analysis was conducted for most studies (N = 22), but this analysis was not always for an observable, behavioral measure, e.g. alternative primary outcomes included diarrhea episodes [23] and microbial counts [24]. Most of the interventions took place in schools (N = 12) or households with children (N = 13); fewer took place in pediatric settings (N = 2) or involved multiple locations, such as schools and other community centers or households (N = 2).…”

Improving Sanitation and Hygiene through Community-Led Total Sanitation: The Zambian Experience

“…An increase in improved sanitation use and reductions in open defecation have been demonstrated in other African countries, including Ghana, Tanzania, and Mali, where CLTS interventions led to increased latrine coverage and use. [13][14][15] In contrast to Mali, where CLTS resulted in roughly a doubling of the percentage of households with a private latrine, 14 the ZSHP resulted in a smaller relative increase in this parameter, although this change was similar to that in the studies conducted in Ghana and Tanzania. Similarly, the Mali study found a larger decrease in reported open defecation at end line (about 24 percentage points) relative to the small change in this important sanitation parameter in Zambia (four percentage points).…”

“…Like the Tanzanian and Indonesian studies, sanitation marketing, which developed the capacity of private sector players such as artisans to provide sanitation services that fulfilled the need for stronger longer lasting toilets at affordable prices, contributed to increased latrine coverage and use. 13,17 A recent meta-analysis found that CLTS was one of a handful of sanitation interventions, along with latrine subsidy/provision interventions, sewage interventions, and sanitation education interventions that had the greatest impact on latrine use and coverage. 19 There appeared to be knowledge sharing in the implementation of the project.…”