WASH Benefits Bangladesh trial: Management structure for achieving high coverage in an efficacy trial

Background: Water, sanitation, and hygiene (WASH) efficacy trials deliver interventions to the target population under optimal conditions to estimate their effects on outcomes of interest, to inform subsequent selection for inclusion in routine programs. A systematic and intensive approach to intervention delivery is required to achieve the high-level uptake necessary to measure efficacy. We describe the intervention delivery system adopted in the WASH Benefits Bangladesh study, as part of a three-paper series on WASH Benefits Intervention Delivery and Performance. Methods: Community Health Workers (CHWs) delivered individual and combined WASH and nutrition interventions to 4169 enrolled households in geographically matched clusters. Households were provided with free enabling technologies and supplies, integrated with parallel behaviour-change promotion. Behavioural objectives were drinking treated, safely stored water, safe feces disposal, handwashing with soap at key times, and age-appropriate nutrition behaviours (birth to 24 months). The intervention delivery system built on lessons learned from prior WASH intervention effectiveness, implementation, and formative research studies. We recruited local CHWs, residents of the study villages, through transparent merit-based selection methods, and consultation with community leaders. CHW supervisors received training on direct intervention delivery, then trained their assigned CHWs. CHWs in turn used the technologies in their own homes. Each CHW counseled six to eight intervention households spread across a 0.2-2.2-km radius, with a 1:12 supervisor-to-CHW ratio. CHWs met monthly with supervisor-trainers to exchange experiences and adapt technology and behaviour-change approaches to evolving conditions. Intervention uptake was tracked through fidelity measures, with a priori benchmarks necessary for an efficacy study. Results: Sufficient levels of uptake were attained by the fourth intervention assessment month and sustained throughout the intervention period. Periodic internal CHW monitoring resulted in discontinuation of a small number of low performers. Conclusions: The intensive intervention delivery system required for an efficacy trial differs in many respects from the system for a routine program. To implement a routine program at scale requires further research on how to optimize the supervisor-to-CHW-to-intervention household ratios, as well as other program costs without compromising program effectiveness.