HIV infection and risk behaviour of primary fentanyl and amphetamine injectors in Tallinn, Estonia: implications for intervention.

BACKGROUND: Following a heroin shortage, fentanyl and 3-methylfentanyl, known as "China White" and "White Persian", have become the most widely used drugs, along with amphetamine, among injecting drug users (IDUs) in Tallinn, Estonia. METHODS: In order to assess the relationships between the injection of fentanyl and amphetamine, and levels of HIV prevalence and risk behaviour, 350 current IDUs were recruited using respondent-driven sampling for an interviewer-administered unlinked cross-sectional survey and HIV testing. IDUs were categorised into groups based on self-report of the main drug used within the last 28 days. RESULTS: 77% (256/331) of participants reported fentanyl and 23% (75/331) amphetamine as their main drug of injection. HIV prevalence was 27% (95% confidence interval [CI]: 18.45-35.51) and 62% (95% CI: 56.97-67.03) among amphetamine and fentanyl injectors, respectively. After adjustment, fentanyl injectors had three times the odds of being HIV positive (adjusted odds ratio [AOR]=2.89; 95% CI: 1.55-5.39). They also had higher odds for injecting in the street with a previously used needle/syringe (AOR=2.39; 95% CI: 1.14-5.04) and sharing a needle/syringe with somebody known to have HIV (AOR=3.00, 95% CI: 1.33-6.79). Fentanyl injectors also had higher odds for lifetime overdose (AOR=3.02, 95% CI: 1.65-5.54). CONCLUSION: The injection of fentanyl is associated with elevated injecting risk behaviour derived from injection practice and situational risk factors, and needs urgently targeted interventions.