Injection network drivers of HIV prevention service utilization among people who inject drugs: results of a community-based sociometric network cohort in New Delhi, India.

INTRODUCTION: Injection drug networks may influence their network members' health-seeking behaviours. Using data from a sociometric injecting partner network of people who inject drugs (PWID) in New Delhi, India, we assessed the role of injecting partner (alter) behaviours on individual engagement in HIV prevention services. METHODS: We enumerated injecting partner linkages among 2512 PWID using coupon referrals and biometric data from November 2017 to March 2020. Participants completed interviewer-administered questionnaires and provided information on injection behaviours, injecting partners, HIV/hepatitis C (HCV) testing and service engagement. Multilevel multiple-membership models (MMMM) evaluated individual PWID HIV testing, medication for opioid use disorder (MOUD) and syringe service engagement as a function of alter attributes, accounting for membership across multiple ego-networks. Logistic regression models assessed parallel associations among socially proximal injecting peers, defined as PWID ≤3 path length from ego. RESULTS: Median age was 26 years; 99% were male. PWID had median 2 injecting partners and 8 socially proximal peers; 14% reported HIV testing, 33% accessed MOUD and 13% used syringe services 6 months prior. In MMMM analyses, PWID with ≥1 versus 0 injecting partners who received HIV testing were significantly more likely to report HIV testing (adjusted odds ratio [aOR]: 2.27, 95% confidence interval [CI]: 1.68-3.16), MOUD (aOR: 1.99, 95% CI: 1.60-2.53) and syringe service use (aOR: 1.66, 95% CI: 1.21-2.39). We observed similar findings for individual MOUD and syringe service use. Having ≥1 versus 0 HIV-positive partners was associated with decreased HIV testing and MOUD but increased syringe service use (aOR: 1.54, 95% CI: 1.09-2.17). PWID with ≥1 versus 0 socially proximal peers who used non-sterile injection equipment reported increased HIV testing (aOR: 1.39, 95% CI: 1.01-1.92), MOUD (aOR: 1.40, 95% CI: 1.10-1.77) and syringe service use (aOR: 1.82, 95% CI: 1.23-2.68). CONCLUSIONS: We found differential associative relationships between individual HIV prevention service engagement and the health or risk behaviours of direct and indirect alters. Characterizing network exposure beyond direct injecting partnerships provided important context on possible mechanisms of behavioural influence. Findings could be leveraged to design peer-based interventions that promote network diffusion of health-seeking behaviours.

Changes in HIV care continuum indicators among community-based samples of HIV-infected people who inject drugs and men who have sex with men across 21 cities in India.

Monitoring key populations' progress towards UNAIDS 90-90-90 targets is essential to achieving HIV/AIDS epidemic control. Using serial cross-sectional data, we evaluated changes in HIV care continuum among people who inject drugs(PWID) and men who have sex with men(MSM) in India. Cross-sectional baseline (2012/2013) and follow-up (2016/2017) samples were recruited using respondent-driven sampling across 21 cities. All participants were tested for HIV and RNA measured in HIV-positive participants. Linear regression was used to model temporal site-level changes in continuum indicators in MSM versus PWID. At baseline, we recruited 2,544 HIV-infected PWID and 1,086 HIV-infected MSM. At follow-up, we recruited 2,517 HIV-infected PWID and 1,763 HIV-infected MSM. At baseline, there were no significant differences in continuum indicators between MSM and PWID. At follow-up, compared to PWID, the proportion of MSM reaching each care continuum indicator-awareness of status, receipt of care, ART use, viral suppression-increased by 15-33 percentage points: 78% of MSM versus 49% of PWID were aware of their status (p < 0.01); 56% of MSM versus 32% of PWID were virologically suppressed (p = 0.05). MSM showed marked improvements across the care continuum, whereas PWID lagged and may require additional intervention. Differential improvement in HIV engagement may necessitate population-specific interventions and routine surveillance to facilitate HIV elimination.