The CombinADO study to assess the impact of a combination intervention strategy on viral suppression, antiretroviral therapy adherence, and retention in HIV care among adolescents and young people living with HIV: protocol for a cluster-randomized controlled trial

Background: Adolescents and youth living with HIV (AYAHIV) have worse HIV outcomes than other age groups, particularly in sub-Saharan Africa (SSA). AYAHIV in SSA face formidable health system, interpersonal- and individuallevel barriers to retention in HIV care, uptake of ART, and achievement of viral suppression (VS), underscoring an urgent need for multi-component interventions to address these challenges. This cluster-randomized control trial (cRCT) aims to evaluate the effectiveness and monitor implementation of a community-informed multi-component intervention ("CombinADO strategy") addressing individual-, facility-, and community-level factors to improve health outcomes for AYAHIV. Methods: This trial will be conducted in 12 clinics in Nampula Province, Northern Mozambique. All clinics will implement an optimized standard of care (control) including (1) billboards/posters and radio shows, (2) healthcare worker (HCW) training, (3) one-stop adolescent and youth-friendly services, (4) information/motivation walls, (5) pill containers, and (6) tools to be used by HCW during clinical visits. The CombinADO strategy (intervention) will be superadded to control conditions at 6 randomly selected clinics. It will include five additional components: (1) peer support, (2) informational/motivational video, (3) support groups for AYAHIV caregivers, (4) AYAHIV support groups, and (5) mental health screening and linkage to adolescent-focused mental health support. The study conditions will be in place for 12 months; all AYAHIV (ages 10-24 years, on ART) seeking care in the participating sites will be exposed to either the control or intervention condition based on the clinic they attend. The primary outcome is VS (viral load < 50 copies/mL) at 12 months among AYAHIV attending participating clinics. Secondary outcomes include ART adherence (self-reported and TDF levels) and retention in care (engagement in the preceding 90 days). Uptake, feasibility, acceptability, and fidelity of the CombinADO strategy during implementation will be measured. Trial outcomes will be assessed in AYAHIV, caregivers, healthcare workers, and key informants. Statistical analyses will be conducted and reported in line with CONSORT guidelines for cRCTs. Discussion: The CombinADO study will provide evidence on effectiveness and inform implementation of a novel community-informed multi-component intervention to improve retention, adherence, and VS among AYAHIV. If found effective, results will strengthen the rationale for scale up in SSA.