HIV prevalence and risk behavior among injection drug users and their sex partners in two Russian cities.

The HIV epidemic in Russia remains concentrated mostly among injection drug users (IDUs). Little is known about the extent to which sexual partnerships are the bridge between IDUs and the general population and create the potential for generalizing the epidemic. IDUs in two Russian cities, Novosibirsk and Ivanovo (N=593), were recruited via respondent-driven sampling. A modified one-step snowball strategy was used to recruit IDU's sex partners who do not themselves use drugs (PIDU, N=82). Sexual behaviors of all participants were assessed using an interviewer-administered questionnaire. All participants provided blood specimens for HIV and hepatitis C virus (HCV) testing. HIV and HCV prevalence among IDUs was 34.0% and 44.4% in Ivanovo and 3.8% and 54.3% in Novosibirsk. HIV prevalence among PIDUs was 6.8% in Ivanovo and 8.7% in Novosibirsk. In both cities large proportions of IDUs reported sexual partnerships with non-IDUs-49.7% in Ivanovo vs. 62.7% in Novosibirsk (p≤0.001) and fewer than one in four IDUs reported constant condom use in such partnerships. This pilot study shows that two IDU populations with a significantly different HIV prevalence both form sexual partnerships with non-IDUs and practice unsafe sexual behavior within such types of partnerships. However, the proportion of PIDUs who form partnerships with other non-IDUs that therefore could lead to a generalization of the epidemic is very different between the two cities and this difference needs to be considered when estimating the spread of HIV into the general population. Unsafe sexual behavior and HIV testing should be specific targets for prevention activities for IDUs and their sex partners in Russia.