Not all injection drug users are created equal: Heterogeneity of HIV, hepatitis C virus, and hepatitis B virus infection in Georgia

Injection drug users (IDU) are widely believed to have accelerated the looming HIV/AIDS epidemic now faced by the Russian Federation and countries of the former Soviet Union. However, IDUs may be heterogeneous with regard to risk behaviors, and a subpopulation may be responsible for the majority of blood-borne pathogen transmission. We studied 926 adult injection drug users (IDU) from the cities of Tbilisi, Batumi, and Poti in Georgia, a small country in the Caucuses region between the Black and Caspian Seas, between 1997 and 1998. Study participants were administered a confidential questionnaire and were tested for antibody to HIV, hepatitis C virus (HCV), hepatitis B virus surface antigen (HBsAg), and hepatitis B core antibody (anti-HBc). Five (0.5%) individuals were positive for HIV; 539 (58.2%), for HCV; 67 (7.2%), for HBsAg; and 475, for (51.3%) anti-HBc. Surveyed individuals, 88.7%, reported sharing needles with others, and needle sharing with more than 10 other individuals versus no sharing was a highly significant predictor (OR: 278.12, 95% CI: 77.57, 997.20) of HCV seropositivity. In adjusted analysis, individuals who usually injected stolen medical/synthetic drugs had significantly lower odds of HCV (OR: 0.38, 95% CI: 0.22, 0.68) and HBV (OR: 0.58, 95% CI: 0.37, 0.90) than individuals most commonly injecting opium. Despite some limitations, these results suggest the presence of substantial heterogeneity between different injection drug-using groups in Georgia. Identification of high-risk IDU subpopulations is vital to efficiently target risk reduction programs and to prevent confounding by risk status in large HIV/AIDS behavioral intervention and vaccine trials.