This trial evaluates the impact of providing comprehensive, community-based and peer-led sexual and reproductive health services to adolescents and young people aged 15 to 24 on their knowledge of their HIV status. The trial includes 20 clusters in two communities, half the clusters receive the intervention. After 18-months of implementation, a cross-sectional survey will be conducted to evaluate the impact of the intervention on the primary outcome: knowledge of HIV status.

Through a cluster-randomised trial, this study will address the research question: Do community-based peer-led interventions increase knowledge of HIV status and coverage of sexual and reproductive health services among adolescents and young people in Lusaka, Zambia, compared to current standard of care? To address this question, the study aims to build a rigorous evidence-base of the effectiveness of community-based, peer-led HIV services designed with and for adolescents and young people living in Lusaka, Zambia, and evidence of the process of delivering such an intervention to support replication and scale-up if the intervention is effective.

The intervention, called Yathu Yathu (For us, by us), was designed with adolescents and young people in a formative research study. The Yathu Yathu intervention includes: 1) delivery of comprehensive sexual and reproductive health services by peer support workers, lay counsellors and a nurse at community-based hubs, and 2) an innovative "prevention points card" system. The prevention points cards are intended to incentivise service use by allowing adolescents and young people to accrue points for accessing services and redeem rewards using these points. At the start of the intervention period, trained enumerators will systematically visit and enumerate all households in the 20 study clusters. For household members aged 15 to 24, the enumerators will offer the individual a prevention points card. A third component is mobile phone-based support groups. These groups will initially be set-up among HIV-positive pregnant women, as a means to offer psychosocial support, with expansion of this portion of the intervention to other groups planned.

To evaluate the impact of the Yathu Yathu intervention, a cross-sectional survey among a random sample of approximately 2000 adolescents and young people will be conducted 18-months after implementation of the intervention. An embedded mixed-method process evaluation will provide evidence of service acceptability, feasibility, and of adolescents and young people's experiences with services. An economic evaluation will provide evidence of the costs and cost-effectiveness of the intervention package. Through these methods, this study will provide a rigorous and comprehensive evidence-base of whether Yathu Yathu can increase adolescents and young people access to sexual and reproductive health services, thereby contributing to their health and well-being.

Inclusion Criteria for the cross-sectional survey to be conducted 18 months after implementation of the Yathu Yathu intervention:

• 16 - 26 years of age at time of the survey (15 to 24 at the time of household enumeration and distribution of the Yathu Yathu prevention points card)
• Residing within the cluster during enumeration of the cluster
• Received a prevention points card at the time of household enumeration
• Able and willing to provide informed consent.

Exclusion Criteria:

• Anything that, in the opinion of the investigator, would preclude informed consent, make study participation unsafe, complicate interpretation of study outcome data, or otherwise interfere with achieving the study objectives.