Background: People who inject drugs (PWID) who are highly connected within their injection drug networks may be important HIV transmission nodes if they frequently share syringes with other PWID and are not engaged in HIV care. In India, HIV transmission fueled by injection drug use is increasing; however, little is known about the associations between injection network size and syringe sharing and viral suppression.
Methods: We recruited 14,481 PWID between October 2012 and December 2013 by respondent-driven sampling across 15 sites in India. Interviewer-administered questionnaires assessed network characteristics, substance use, HIV testing experience, and access to health services. We used multilevel logistic regression modeling to evaluate the relationship between injection drug network size and (1) syringe sharing at last injection and (2) viral suppression among HIV-positive participants (<150 copies/mL).
Findings: The median injection network size was 3 (interquartile range: 1-5), and 7% of participants injected with >10 members in the past 30 days. PWID who had >10 members in their network were 1.65 times (95% confidence interval: 1.12 to 2.42, P = 0.0111) more likely to have shared a syringe at last injection compared with those in the 0-1 members in their drug networks. In addition, individuals with the largest injection drug networks were 31% (95% confidence interval: 0.53 to 0.90, P = 0.006) less likely to be virally suppressed compared with those in the smallest injection drug networks.
Discussion: Individuals with larger networks may be important in HIV transmission within injection drug networks because they were the most likely to engage in recent syringe sharing and least likely to be virally suppressed.