Results
The trial enrolled 502 index (194 [39%] in Vietnam, 187 [37%] in Ukraine, and 121 [24%]) in Indonesia) and 806 partner participants (305 [38%] in Vietnam, 318 [39%] in Ukraine, and 183 [23%]) in Indonesia). A majority were men (87%, 1143/1308); most women (77%, 127/165) enrolled at the Ukrainian site. The median age at enrollment was 34 years (IQR: 30, 38), with no significant difference by study group. Participants in Indonesia were slightly younger compared to Ukraine and Vietnam (median age 32, 34, 35, respectively). A majority reported opioid use in the past three months before baseline (99%, 1299/1308). The median lifetime duration of drug injecting was 13 years (range 0–37) and the median number of injecting days per month was 25 (range 0–31). Detailed baseline characteristics of the study cohort are presented in a previous report [Median follow-up time was 1.2 years (IQR: 0.9–1.5); 3.8% of indexes (9/502) and 6.6% of partners (29/806) were lost to follow-up, and their survival status could not be verified.