Comparing the effect of independent and combined interventions of household chlorination and handwashing on diarrhea of under-fives in rural Dire Dawa, Eastern Ethiopia: a cluster randomized controlled trial

INTRODUCTION: in poorly developed countries, no single intervention is adequate to interrupt diarrhea occurrence in rural households. However, the effect sizes of multiple interventions and participants combined adherence to the interventions are understudied. This study aimed at comparing combined intervention of water sanitation and hygiene (WASH) with each individual intervention in reducing diarrhea among under-five children in rural Dire Dawa. METHODS: a cluster randomized controlled factorial trial was conducted between October 2018 and January 2019. Householders in the first, second and third arms received waterguard, soap and both, respectively. However, householders in the control arm were followed with their customary practices. Generalized estimation equations (GEE) with log link Poisson distribution was used to compute adjusted incidence rate ratio and the corresponding 95% CIs. RESULTS: overall, 36% (aIRR = 0.64, 95% CI: 0.57 - 0.73), 41% (aIRR = 0.588, 95% CI: 0.53 - 0.65), and 41% (aIRR = 0.585, 95% CI: 0.53 - 0.65) reduction in incidence of diarrhea was observed in the water treatment, handwashing and combined arms, respectively. This study showed no additional benefit of combining the two interventions than the individual intervention. CONCLUSION: we recommend implementing either household water disinfection using sodium hypochlorite or household handwashing with hand hygiene promotion independently at large scale to vulnerable population to reduce diarrheal morbidity.