Sustaining Engagement in HIV Prevention Program Among Adolescents and Young Adults (AYA) in Nigeria: Longitudinal Secondary Analysis

Background: Adolescent and young adult (AYA; 14-24 years old) engagement in HIV programs is often transient, and socioeconomically marginalized AYA are less engaged. Few studies have examined whether engagement can be sustained over time in HIV prevention programs. This study examines correlates of sustained AYA engagement over 24 months in an HIV prevention program in Nigeria. Methods: We conducted a secondary data analysis of longitudinal data from an HIV prevention program among AYA in 32 local communities in Nigeria from 2021 to 2023. In the study, participants were invited to join crowdsourcing open calls, peer-led support meetings, and other activities. Engagement was assessed using a modified 12-item Tiffany-Eckenrode Program Participation Scale (0-4 per item) at months 3, 6, 12, 18, and 24. Sustained AYA engagement was defined as a mean score >/= 3.0/4.0 in at least three consecutive contacts (approximately 12 months). Longitudinal analysis was conducted using generalized estimating equations, and state-level contextual analysis was done using a linear mixed model. Results: A total of 1,259 AYA were included. The mean age was 19.8 years; most were students (n=954,75.8%) and unemployed (n=810,64.3%). The mean participation score remained consistently high throughout the 24 months (3.245 +/-0.535 to 3.319 +/-0.556), with 73.0% demonstrating sustained engagement. Students were less likely to sustain engagement compared to non-students (aRR = 0.91; 95% CI: 0.84-0.97). Unemployed AYA were more likely to sustain engagement than employed AYA (aRR= 1.09; 95% CI:1.03-1.14). States with higher poverty had significantly greater sustained AYA engagement. All the main findings were robust in sensitivity analyses. Conclusion: AYA engagement in the HIV self-testing implementation was high and sustained over 24 months, especially among socio-economically disadvantaged populations. This study supports the use of a participatory, AYA-led approach in sustaining AYA engagement in HIV prevention programs and has implications for the equity of HIV programs.