Trends in HIV incidence following scale-up of harm reduction interventions among people who inject drugs in Kachin, Myanmar, 2008-2020: analysis of a retrospective cohort dataset.

ABSTRACT

Background: People who inject drugs (PWID) in Kachin, Myanmar, have a high HIV prevalence (>40%), but there is no data on incidence. We used HIV testing data from three harm reduction drop-in centres (DIC) in Kachin (2008-2020) to determine HIV incidence trends among PWID and associations with intervention uptake. Methods: Individuals were HIV-tested at first DIC visit and periodically thereafter, during which demographic and risk behaviour data were collected. Two DIC provided opioid agonist therapy (OAT) from 2008. Monthly DIC-level needle/syringe provision (NSP) data was available from 2012. Site-level 6-monthly NSP coverage was denoted low, high, or medium if it was below the lower quartile, above upper quartile, between these quartiles of provision levels over 2012-2020, respectively. HIV incidence was estimated by linking subsequent test records for those initially testing HIV-negative. Associations with HIV incidence were examined using Cox regression. Findings: Follow-up HIV testing data was available for 31.4% (2227) of PWID initially testing HIV-negative, with 444 incident HIV infections during 6266.5 person years (py) of follow-up. Overall HIV incidence was 7.1 per 100 py (95% confidence interval 6.5-7.8), which decreased from 19.3 (13.3-28.2) in 2008-11 to 5.2 per 100 py (4.6-5.9) in 2017-20. In the full PWID incidence dataset after adjustment for various factors, recent (≤6 weeks) injecting (aHR 1.74, 1.35-2.25) and needle sharing (aHR 2.00, 1.48-2.70) were associated with higher incidence, while longer injection careers were associated with reduced incidence (aHR 0.54, 0.34-0.86, for 2-5 yrs vs <2 yrs). In a reduced dataset including data on OAT access and NSP coverage (2012-2020 for two DIC providing OAT), being on OAT during follow-up was associated with reduced HIV incidence (aHR 0.36, 0.27-0.48, compared to never being on OAT) as was high NSP coverage (aHR 0.64, 0.48-0.84, compared to medium syringe coverage). Interpretation: Although HIV incidence is high among PWID in Kachin, data suggests it has decreased since the scale-up in harm reduction interventions. Funding: US NIH, Médecins du Monde.