Current drug use patterns and HIV and HCV prevalence among people who inject drugs in suburban areas of Malaysia

Introduction: National surveillance data in Malaysia has observed a marked reduction in the number of new HIV cases among people who inject drugs (PWID) in the past decade. This study sought to estimate the current prevalence and associated risk factors of HIV and hepatitis C virus (HCV) among PWID in suburban areas of Klang Valley, Malaysia. Methods: Between September 2021 and March 2022, a cross-sectional, respondent-driven sampling survey was conducted. Participants completed rapid HIV and HCV testing as well as social and behavioural assessments. Factors associated with HIV- and HCV-positive results were estimated using logistic regression. Results: Four-hundred individuals were recruited in the study, of whom 382 (94%) were men. The prevalence of HIV and HCV was 5.5% (95% confidence interval [95% CI]: 3.6–8.3) and 40.5% (95% CI: 35.7–45.5), respectively. Current heroin and amphetamine-type stimulant (ATS) use, regardless of injection or non-injection use, were reported by 340 (85.0%) and 328 (82.0%) individuals, respectively. Past exposure to the criminal justice system (lock-ups, prison and compulsory drug detention centres) was associated with both HIV (Adjusted odds ratio [aOR] = 3.47, 95% CI: 1.33–10.2) and HCV (aOR = 3.32, 95% CI: 2.06–5.39)-positive results. Additionally, HIV-positive results were associated with current ATS use (aOR = 0.31, 95% CI: 0.12–0.86). Meanwhile, HCV-positive results were associated with current heroin use (aOR = 2.44, 95% CI: 1.16–5.48), lifetime enrolment in methadone treatment (aOR = 2.30, 95% CI: 1.23–4.27), current methadone treatment (aOR = 0.46, 95% CI: 0.23–0.92) and current mixing of drugs through injection use (aOR = 1.80, 95% CI: 1.08–3.03). Conclusions: This study observed low HIV prevalence among PWID, primarily associated with ATS use, while HCV prevalence, linked to heroin use, remained high. Higher odds of being HCV positive among PWID who reported to have ever but not currently enrolled in methadone programmes indicate that treatment may not be continuous once initiated, potentially due to exposure to the criminal justice system. These findings underscore the need for a dual approach: enhanced harm reduction programmes for PWID and a legal reform to address potential barriers posed by criminalization.