Increasing HIV prevalence among injection drug users in St. Petersburg, RF

Background: Russia is experiencing a major HIV epidemic driven in great part by transmission among injection drug users (IDUs). The city of St. Petersburg alone has identified more 30,000 infections with prevalence among IDUs reaching 30% in 2002. Current data are needed to target appropriate interventions. Methods: IDU participants were recruited into a cross-sectional sample using respondent-driven sampling, a robust variant of chain referral sampling. Sex partners of IDUs were also recruited by chain referral. Individuals were tested for HIV and interviewed to collect data focused on recent episodes of drug use and sexual intercourse. A second sample, individuals with newly diagnosed HIV infection with no history of injection drug abuse, was recruited by convenience from the city AIDS center. Results: HIV prevalence in the sample of 412 IDUs was 47% (194 confirmed HIV seropositives). Only 44 IDUs (10.6%) referred a sex partner who was not him/herself an IDU. Nine of these 44 (20.5%) were HIV positive. Conversely, of 112 HIV positive non-IDUs, 28 (25.0%) reported an IDU partner. The geographic spread of HIV from spatial clusters identified in 2002 confirmed that the epidemic remained concentrated among IDUs is discrete neighborhoods. Conclusions: The data suggest that the HIV epidemic in St. Petersburg remains unabated but concentrated in IDUs with little sexual contact between IDUs and non-IDUs. It is also apparent that the geographic clustering can be exploited to direct interventions to reduce the spread of HIV and provide secondary prevention to HIV positives.