Evaluation of an Educational Intervention on Abscesses in People Who Self-inject Drugs

The goal of this cluster randomised controlled trial (cRCT) is to to evaluate the effectiveness of an educational intervention combining training in hand-washing with the supply of MONO-RUBs on the reduction of skin abscesses (both observed and self-reported) in people who inject drugs (PWID). The main questions it aims to answer are: * does an educational intervention change the incidence of injection-related skin and soft tissue infection (SSTI) like abscesses in PWID? * does the educational hand-washing intervention improve injection practices in terms of hand-hygiene in PWID? According to cluster randomisation, PWID will be assigned to: * Standard harm reduction (HR) services to reduce abscesses plus an educational hand-washing intervention (intervention arm) * Standard HR services only (control arm) To measure the effectiveness of the educational hand-washing intervention, the primary outcome will be the reduction in abscess prevalence compared in both groups. Statistical analyses for the primary outcome will involve comparing the reduction in abscess prevalence in the intervention arm with that in the control arm. This prevalence will be measured from observed and self-declared data, collected from the injection-site photographs and the face-to-face injection-related SSTI questionnaire, respectively.