INTRODUCTION:
Youth continue to face barriers to accessing HIV prevention services, including stigma, limited awareness, and inadequate youth-friendly programs. Engaging youth in the design and delivery of interventions is critical to improving health outcomes and reducing new HIV infections. This study examines the impact of youth engagement on HIV prevention program effectiveness.

METHODS:
A cross-sectional mixed-methods study was conducted among 500 adolescents and young adults aged 15-24 in Anambra State, Nigeria. Quantitative data were collected using structured questionnaires assessing HIV knowledge, uptake of prevention services, and self-reported behavioral changes. Qualitative data were obtained through focus group discussions exploring perceptions of youth-led initiatives. Data were analyzed using descriptive statistics, chi-square tests, and thematic analysis for qualitative data.

RESULTS:
Participants in youth-engaged programs demonstrated higher HIV knowledge scores (mean 82.5%) compared to those in non-youth-led programs (mean 65.4%). Uptake of HIV testing increased by 25% among participants involved in peer-led activities. Qualitative findings highlighted that youth involvement enhanced program acceptability, reduced perceived stigma, and fostered peer support. Key themes included empowerment, ownership, and improved communication between health workers and adolescents.

CONCLUSIONS:
Youth engagement in HIV prevention programs significantly improves knowledge, service uptake, and perceived accessibility. Incorporating adolescents and young adults in program design and delivery enhances effectiveness and fosters sustainable behavior change. Public health interventions should prioritize youth-led approaches to address HIV among adolescents and young adults, particularly in settings with high stigma and limited access to services.