Abstract
Hand hygiene prevents infectious diseases in schoolchildren, but objective assessment of technique remains largely unexplored in school settings. The aim of the present study is to evaluate a school-based intervention on hand hygiene in primary schools. We conducted a controlled school-based community intervention study with school-level allocation, using a before-after repeated-measures design in two primary schools in Tarragona, Spain. A total of 126 children aged 8-12 years participated (64 intervention, 62 control). The intervention combined a 30-min session on the 7-step alcohol-based hand rub technique with feedback using fluorescent hand rub and a custom UV device. Hand hygiene quality was measured at baseline and at 1, 3, and 6 months as the proportion of total hand surface area adequately covered, including the palmar and dorsal surfaces of both hands. Images were analysed using an artificial intelligence-assisted tool to support more standardised outcome assessmentLongitudinal effects were analysed exploratorily with a beta mixed-effects regression model. Adjusted hand coverage was similar between groups at baseline. At 1 month, both schools showed increased adjusted coverage. From 3 months onwards, trajectories diverged. The intervention school showed higher adjusted coverage than the control school at 3 months (adjusted mean difference 0.031; 95% CI: 0.010-0.052) and 6 months (0.041; 95% CI: 0.021-0.061). This exploratory study suggests that combining structured hand hygiene education with immediate UV visual feedback may contribute to sustained improvements in hand hygiene technique in primary school settings. The AI-assisted image-analysis workflow supported partial standardisation of outcome assessment, although the fluorescence-detection step required human supervision.