RESUMO
BACKGROUND: HIV seroprevalence in Nigeria is increasing among men who have sex with men (MSM) from 14% to 2007 to 23% in 2014, threatening progress towards ending the epidemic in the country. Expanding access to HIV testing and linkage to care for key populations, like young MSM (YMSM), is critical to end the HIV epidemic in Nigeria. The Intensive Combination Approach to Roll Back the Epidemic in Nigerian Adolescents (iCARE Nigeria) pilot intervention successfully implemented a combination of evidence-based interventions utilizing peer navigators and popular social media apps and platforms to reach young men at risk for HIV exposure, including YMSM. We conducted sequential mixed methods explanatory implementation research to expand on the previously reported effectiveness and implementation outcomes and to explore the determinants and strategies which contributed to primary study results. METHODS: We conducted key informant interviews and focus group discussions with 2 peer navigators and 3 study staff at the end of the pilot. We used directed content analysis to understand the quantitative results from the pilot. Using the Implementation Research Logic Model, we were able to identify and map strategies through mechanisms of action from barriers addressed to the reported implementation outcomes including feasibility, acceptability fidelity and adoption. RESULTS: We found that iCARE Nigeria's pilot intervention implementers reported high feasibility, acceptability fidelity and adoption were associated with implementation of strategies which addressed many challenging contextual factors, including social stigma, online social networking, legal barriers surrounding MSM behavior, and the COVID-19 pandemic. These strategies included integration of stakeholders' interests, selection of experienced peer navigators including from the targeted population, training and supportive supervision using an implementation guide, ensuring safety (COVID and legal) and identification of clinics serving the targeted population. CONCLUSION: Mixed methods using implementation research frameworks provided insights into the strategies and barriers and facilitators they addressed which may explain the success of the pilot. These results can inform strategies needed to scale-up the intervention to youth including YMSM in other areas in Nigeria and the region. TRIAL REGISTRATION ISRCTN: ISRCTN94590823, https://doi.org/10.1186/ISRCTN94590823.