Background: People who use drugs including people who inject drugs (PWUD/ID), sex workers (SWs) and men who have sex with men (MSM) are at increased risk of HIV and viral hepatitis infection. Limited epidemiological data on the infections exists in key populations (KPs) in South Africa. We investigated the prevalence of hepatitis B (HBV), hepatitis C (HCV) and HIV and selected risk factors among these KPs to inform effective responses. Methods: We used convenience sampling to recruit a targeted 3500 KPs accessing HIV-related health services across Cape Town (SWs, MSM, PWUD/ID), Durban (SWs, PWUD/ID), Pietermaritzburg (SWs), Mthatha (SWs), Port Elizabeth (SWs), Johannesburg (MSM) and Pretoria (MSM and PWUD/ID) into a cross-sectional survey. An interviewer questionnaire to assess socio-demographic characteristics, drug use and sexual risk practices, was administered. HBV surface antigen (HBsAg); HCV antibody, viral load and genotype, and HIV antibody, was tested. Results: Among the 3439 people included in the study (1528 SWs, 746 MSM, 1165 PWUD/ID) the median age was 29 years, most participants were black African (60%), and 24% reported homelessness. 82% reported substance use in the last month, including alcohol (46%) and heroin (33%). 75% were sexually active in the previous month, with condom use at last sex at 74%. HIV prevalence was 37% (highest among SWs at 47%), HBsAg prevalence 4% (similar across KPs) and HCV prevalence was 16% (highest among PWUD/ID at 46%). Conclusions: HBV, HCV and HIV pose a health burden for KPs in South Africa. While HIV is key for all included KPs, HCV is of particular importance to PWUD/ID. For KPs, HBV vaccination and behavioural change interventions that support consistent condom and lubricant access and use are needed. Coverage of opioid substitution therapy and needle and syringe services, and access to HCV treatment for PWUD/ID need to be expanded.
