Risk for Heterosexual HIV Transmission Among Non-Injecting Female Partners of Injection Drug Users in Estonia.

The HIV epidemic in Estonia, as with other eastern European countries, is currently concentrated among injection drug users (IDUs). Non-IDUs who have IDU sex partners could serve as a potential bridge in an expanding epidemic. We applied HIV transmission modelling to data collected from non-IDU/IDU heterosexual couples in Kohtla-Järve, Estonia to estimate HIV risk from IDUs to their sex partners based on self-reported sexual behaviors shared by the couple. IDUs and their current main non-injecting sex partners were recruited for an interviewer-administered survey and HIV testing. Bernoulli modelling techniques were applied to estimate the risk of HIV transmission (incidence) among HIV negative non-injecting female partners of male IDUs. The estimated HIV incidence in this population of non-injecting women with only main sexual partners in the last 6 months ranged from 3.24 to 4.94 HIV seroconversions per 100 person years depending on the value used in the models for the per act transmission rate during acute stage infection. Non-IDUs who have IDU sex partners are at high risk for HIV and could serve as a potential bridge to a more generalized epidemic. Whether this might lead to an expansion of the HIV epidemic beyond core groups in Estonia or other Eastern European countries warrants closer study.

Emergent properties of HIV risk among injection drug users in Tallinn, Estonia: synthesis of individual and neighbourhood-level factors.

OBJECTIVES: HIV/AIDS risk is embodied within multiple levels including structural and social levels. The aim of this study was to assess the effects of neighbourhood characteristics on HIV prevalence among injection drug users (IDU) residing in the area of Tallinn, Estonia in 2007. METHODS: A cross-sectional, multilevel design collecting individual-level data--a behaviour survey including data on self-reported residency and HIV antibody testing among 350 IDU and neighbourhood-level data--aggregate measures on socio-demo-economic residential characteristics from the 2000 Estonian census. Geocoding and multilevel modelling analysis was employed. RESULTS: Among the 350 IDU recruited, earlier age at first injection, fentanyl as the main injection drug, receptive syringe sharing, main income source other than legal employment and ever attended a syringe exchange programme remained significantly associated with increased odds of anti-HIV positivity in the multivariable analysis involving individual effects with no predictors at the neighbourhood level. In the multilevel model, individual (earlier at IDU initiation AOR 1.86, 95% CI 1.01 to 3.44; injecting opioids AOR 4.43, 95% CI 2.74 to 7.18; receptive syringe sharing AOR 2.51, 95% CI 1.86 to 3.37; main income source other than work AOR 2.04, 95% CI 1.32 to 3.14; ever attended a syringe exchange programme AOR 2.58, 95% CI 1.83 to 3.61) and neighbourhood level (higher unemployment rate AOR 5.95, 95% CI 2.47 to 14.31; greater residential change AOR 1.89, 95% CI 1.09 to 3.26) emerged as significant predictors of individual HIV-positive status. CONCLUSIONS: Our results indicate that both individual-level and emergent neighbourhood-level factors contribute to HIV risk among IDU and are amenable for preventive interventions.

Knowledge of HIV serostatus and risk behaviour among injecting drug users in Estonia.

We used the findings from two, cross-sectional studies of HIV serostatus and risk behaviours to assess the effects of knowledge of HIV serostatus and risk behaviours (relating to sex and injection drug use) among injecting drug users (IDUs). Respondent-driven sampling was used simultaneously at two sites in Estonia (the capital Tallinn, and the second-largest city of Ida-Virumaa County, Kohtla-Jarve). The research tool was an interviewer-administered survey. Biological samples were collected for HIV testing. Participants were categorised into three groups based on HIV testing results and self-report on HIV serostatus: HIV-negative (n=133); HIV-positive unaware of their serostatus (n=75); and HIV-positive aware of their serostatus (n=168). In total, 65% of the participants tested positive for HIV. Of those 69% were aware of their positive serostatus. HIV-positive IDUs aware of their serostatus exhibited more risk behaviours than their HIV-positive counterparts unaware of their serostatus or HIV-negative IDUs. Effective prevention of HIV among IDUs should therefore, include programmes to reduce high-risk sexual and drug use behaviours at the public health scale and enhanced prevention efforts focusing on HIV-infected individuals.