Peer-led intervention to prevent and reduce STI transmission and improve sexual health in secondary schools (STASH) : protocol for a feasibility study

Background:Young people in the UK are at highest risk of sexually transmitted infections and report higher levelsof unsafe sex than any other age group. Involving peer supporters in intervention delivery is acceptable to studentsand effective in reducing risk behaviours via‘diffusion of innovation’, particularly where peer supporters areinfluential in their networks. Informal peer-led interventions offer a useful alternative to peer-led didactic teaching,which has shown limited effects. Building on the successful ASSIST anti-smoking intervention, the‘STis And SexualHealth’(STASH) intervention involves identification and recruitment of the most influential students as peersupporters, training and support to these students by specialist trainers, positive sex and relationships messages,spread by peer supporters to their friendship groups in person and via social media. Methods/design:This protocol describes a feasibility trial of the STASH intervention in six schools. It builds on anearlier study phase of intervention co-development using patient and public involvement (PPI) activities, followedby a pilot of intervention components and evaluation tools in one school. Participants are fourth year (S4) students(aged 14–16) in state-funded Scottish secondary schools who have received some level of teacher-led sexeducation. The previous cohort of S4 students (those completing S4 in the year prior to the intervention) will serveas controls. Data will be collected from controls (month 16), baseline (month 20–21) and follow-up (month 27–30)via a web-based questionnaire, which will measure (and test the reliability of) primary outcome measures for aphase III trial (delayed initiation of/abstinence from sex and consistent condom use), secondary outcomes andmediators of sexual behaviour (including school climate and social networks). The main feasibility outcome iswhether the study meets pre-set progression criteria regarding feasibility and acceptability, measured largely via aprocess evaluation (basic measures in all 6 schools and in-depth in 2-4 schools). An economic evaluation reportingcosts alongside consequences will be conducted. Discussion:This study will inform decisions on the feasibility, design and sample size for a phase III effectivenesstrial to assess whether the STASH intervention is effective in reducing the risk of sexually transmitted infections inyoung people. Trial registration:ISRCTN9736917