Effectiveness of a multi-component hand hygiene intervention in primary schools: a cluster randomised controlled trial in Nigeria

Background Handwashing with soap reduces infection transmission in schools, yet sustained hygiene service delivery is limited in humanitarian contexts. Trials of handwashing interventions show inconsistent effects. We evaluated a multi-component hand hygiene intervention’s effect on children’s observed handwashing. Methods We conducted a cluster randomised controlled trial in 26 primary schools in Borno State, Nigeria, assessing outcomes at 2 and 8 months. Using covariate-constrained randomisation, schools were allocated (1:1) to a control (data collection only) or intervention arm (handwashing stations, behaviour change activities and operations and maintenance support). The primary outcome was observed handwashing before eating. Blinding was not feasible. The trial is registered on ClinicalTrials.gov (NCT05964478). Results At baseline, 483 children in 13 control schools and 481 in 13 intervention schools were observed. At follow-up 1 (FU1), 403 children in 13 control schools and 381 in 11 intervention schools were observed; at FU2, 650 children in 13 control schools and 426 in 11 intervention schools were observed. Intervention schools had higher observed handwashing than control schools before eating at both follow-ups (FU1: OR=5·5, 95% CI 2·4 to 12·8, p<0·001; FU2: OR=8·6, 95% CI 2.7 to 27.3, p<0·001) and after-toilet use at FU2 only (FU2: OR=44·5, 95% CI 5.3 to 376.5, p<0·001). Escherichia coli remained high, with no significant reduction. Conclusion The intervention increased observed handwashing at key moments, but soap use remained low and hand contamination did not improve. Programmes should ensure reliable water and soap supply, place facilities at points of use, and allocate recurring budgets for consumables and maintenance.