Data for this study were collected from two prospective cohorts of PWUD in Vancouver, Canada, the Vancouver Injection Drug Users Study (VIDUS) and the AIDS Care Cohort to Evaluate Exposure to Survival Services (ACCESS). These cohorts have been described previously in detail (Bach et al., 2015; Strathdee, 1998; Wood, 2008). In brief, participants in both cohorts have been recruited since May 1996 through street outreach in the Downtown Eastside, an area with a high prevalence of substance use in Vancouver. VIDUS is a cohort of HIV-negative PWUD who are eligible for participation in the study if they are at least 18 years old and have injected illicit drugs at least once in the past month prior to study enrollment. ACCESS is a study of HIV-positive adults who have used illicit drugs in the month prior to study enrollment. VIDUS participants who seroconvert to be HIV-positive are transferred to the ACCESS study.
