Peer community health workers improve HIV testing and ART linkage among key populations in Zambia: retrospective observational results from the Z-CHECK project, 2019-2020.

Introduction: Zambia has made tremendous progress towards HIV epidemic control; however, gaps remain among key populations (KPs), such as female sex workers (FSWs), men who have sex with men (MSM), people who inject drugs (PWID) and people in prisons and enclosed settings due to cultural, social and legal barriers. The University of Maryland, Baltimore Zambia Community HIV Epidemic Control for Key Populations (Z-CHECK) project aimed to improve HIV case-finding, linkage and treatment adherence at the community level for KPs in Zambia. We describe Z-CHECK strategies and examine HIV positivity yield and antiretroviral therapy (ART) linkage among KPs to inform ongoing programme improvement.

Methods: Z-CHECK recruited, trained and deployed peer community health workers (CHWs) for KP groups, with ongoing mentorship in community engagement. CHWs offered HIV testing in safe spaces and escorted newly HIV-diagnosed clients for same-day ART initiation. Z-CHECK also reached out to KP community leaders and gatekeepers for KP mobilization and trained healthcare workers (HCWs) on KP services and sensitivity. We conducted a retrospective observational review of routinely collected aggregate data for KPs aged ≥15 years at high risk for HIV transmission across five districts in Zambia from January 2019 to December 2020.

Results: Z-CHECK provided HIV testing for 9211 KPs, of whom 2227 were HIV positive (positivity yield, 24%). Among these, 1901 (85%) were linked to ART; linkage for MSM, FSW, PWID and people in prisons and enclosed settings was 95%, 89%, 86% and 65%, respectively. Programme strategies that contributed to high positivity yield and linkage included the use of peer KP CHWs, social network testing strategies and opportunities for same-day ART initiation. Challenges to programme implementation included stigma and discrimination among HCWs, as well as KP CHW attrition, which may be explained by high mobility.

Conclusions: Peer CHWs were highly effective at reaching KP communities, identifying persons living with HIV and linking them to care. Engaging KP community gatekeepers resulted in high diffusion of health messages and increased access to health resources. The mobility of CHWs and HCWs is a challenge for programme implementation. Innovative interventions are needed to support PWID and people in prisons and enclosed settings.