The high incidence of HIV infection places St Petersburg among the worst IDU-concentrated epidemics in Europe. Interventions targeting psychostimulant and heroin users and their accompanying behaviors such as frequent injections and increased sexual activity are needed immediately.

The purpose of this analysis was to estimate human immunodeficiency virus (HIV) prevalence and testing patterns among injection drug users (IDUs) in St. Petersburg, Russia. HIV prevalence among 387 IDUs in the sample was 50%. Correlates of HIV-positive serostatus included unemployment, recent unsafe injections, and history/current sexually transmitted infection. Seventy-six percent had been HIV tested, but only 22% of those who did not report HIV-positive serostatus had been tested in the past 12 months and received their test result. Correlates of this measure included recent doctor visit and having been in prison or jail among men. Among the 193 HIV-infected participants, 36% were aware of their HIV-positive serostatus. HIV prevalence is high and continuing to increase in this population. Adequate coverage of HIV testing has not been achieved, resulting in poor knowledge of positive serostatus. Efforts are needed to better understand motivating and deterring factors for HIV testing in this setting.

The HIV epidemic that began in Russia in the mid-1990s has been concentrated mostly among drug users (DUs). Recent evidence of increasing HIV cases among non-DUs attributed to sexual behavior raises potential concern about a more generalized epidemic. The purpose of this analysis is to examine the potential for HIV transmission from DUs to their non-DU sex partners. Analyses are conducted using data collected during [2005][2006][2007][2008] in St. Petersburg, Russia. A total of 631 DUs were recruited into the sample with an HIV prevalence of 45%. A majority (84%) of DUs reported being sexually active in the past 6 months, and the DU status of their sex partners was reported as follows: 54% DU, 40% non-DU, and 6% unknown DU status. In 41% of partnerships with an HIV-negative or unknown status partner not known to be DU (potential bridging partnerships), the last reported intercourse was unprotected. Female DUs with potential bridging partnerships were more likely than male DUs to be younger and report homelessness and to have multiple or new sex partners. Many non-DU sex partners of DUs enrolled in the study reported new sex partners in the past 6 months (66%), unprotected intercourse at last sex (60%), and multiple sex partners in the past 6 months (48%). HIV prevalence in this group was 15% (eight out of 53). The high prevalence of HIV among DUs, their sexual contact with non-DUs, and the high-risk sexual behaviors of this potential bridging population together indicate the real potential for an increasingly generalized epidemic. The degree to which there will be further transmission from non-DU sex partners of DUs who exhibit high levels of sex risk behaviors to other non-DU sex partners deserves further study.

There are limited data on the genetic complexity of human immunodeficiency virus type 1 (HIV-1) after transmission among a cohort of injection drug users (IDUs). We used single-genome amplification of HIV-1 env to determine the genotypic characteristics of virus among IDUs with acute infection in St Petersburg, Russia. Our results indicate that a single variant was transmitted in a majority of cases (9 of 13 participants), which is analogous to what is observed in sexual transmission. These data are most consistent with a genetic bottleneck during transmission by injection drug use that is due to a small inoculum, which most often results in the transmission of a low-complexity viral population.

The epidemic of HIV in St. Petersburg, which is currently concentrated among injection drug users (IDUs), may be penetrating into the general population. Non-IDUs who have IDU sex partners (SP) could be potential bridges in an expanding epidemic. To investigate potential bridges, we accrued a convenience sample of 288 non-IDUs whose HIV diagnosis was attributed to sexual transmission and we determined the proportion that had IDUs among their SP. Having IDU SP ever (lifetime) and IDU SP in the last year were the key variables for the analysis of potential bridges in this study. The interaction of gender and age was found to be a significant predictor of having lifetime IDU SP (p = 0.006, chi (2) test) and IDU SP in the last year (p = 0.05, chi (2) test): females aged 26 and younger were more likely to have both lifetime IDU SP and IDU SP in the last year. Among the group of young females, 46% reported ever having an IDU SP. Out of young women reporting ever having an IDU SP, 85% also reported at least one lifetime non-IDU SP. Among the females aged 26 or younger, a lower level of education (odds ratio [OR] = 2.7, confidence interval [CI] = 1.1-6.7), being born in St. Petersburg (OR = 2.9, CI = 1.2-7.2), and alcohol use in the last 30 days (OR = 3.5, CI = 1.3-9.6) were significant correlates for ever having had an IDU SP. Urgent efforts are necessary to expand HIV prevention to target the potential bridging population to prevent further transmission.