Population and setting
HIV INFECTION, RECRUITMENT
The study was conducted at three sites (Jakarta, Indonesia; Kyiv, Ukraine; and Thai Nguyen, Vietnam). The sites were selected based on estimated high HIV incidence and prevalence among PWID. Participants were recruited in a city hospital (Jakarta), two district health centers (Thai Nguyen), and a community-based harm reduction program (Kyiv). The main recruitment methods were community outreach and peer referral. Study enrollment occurred between April of 2015 and June of 2016 and follow-up in the main phase continued until June 2017.All participants were required to be between 18–45 years of age (the maximum allowed age increased to 60 years after 8 months into the study), active injectors (defined as have injected at least 12 times in the past 3 months), planning to stay in the study area for one year, and able and willing to provide informed consent. Additional criteria for index participants included confirmed HIV infection, HIV viral load ≥ 1,000 copies/mL, CD4 count > 50 cells/μL, and ability to recruit at least one HIV-negative injection partner. Partners had to have HIV-negative test results at screening and have a confirmed relationship with the index (verified by matching the physical description).