ABSTRACT:
Children are among the most vulnerable to poor water, sanitation, and hygiene (WASH) conditions, which expose them to enteric diseases such as diarrhoea and parasitic infections1,2. School-based WASH interventions aim to reduce hygiene-related illnesses, improve educational outcomes, and influence broader community practices3. This study evaluated the impact of a teacher-led, behaviour-change-driven WASH program “Washed-Up” on hygiene practices and illness-related absenteeism among primary school children in urban Nigeria. A cluster-randomised controlled trial was conducted in 45 primary schools across Lagos, with 22 schools receiving the intervention and 23 serving as controls. The intervention included teacher training workshops, interactive WASH education through stories, games, and songs, behavioural diaries to reinforce habits, and the formation of hygiene clubs. Data were collected at baseline and end-line using structured questionnaires, observation checklists, and focus group discussions. Multilevel mixed-effects logistic and linear regression models were used to assess outcomes. At baseline, although 78% of students understood hygiene principles, only 42% practised proper handwashing consistently. The Washed-Up program effectively bridged this gap, resulting in a 65% increase in handwashing frequency. Students demonstrated improved hygiene behaviours, such as washing their hands before meals and after using the toilet. Facility utilisation increased by 54%, and barriers like lack of soap or clean water decreased by 47%. Additionally, self-reported diarrhoea cases dropped by 38%, and absenteeism due to hygiene-related illnesses declined by 32%. This study underscores the effectiveness of school-based WASH programs in shaping health behaviours and enhancing child well-being. It advocates for integrating structured WASH education into Nigeria’s primary school curriculum as a scalable solution to improve hygiene practices and reduce preventable diseases among school-aged children.