HIV/AIDS prevalence and behaviour in drug users and pregnant women in Kashgar Prefecture: case report

Multilevel analysis of HIV related risk behaviors among heroin users in a low prevalence community

BACKGROUND

Injecting drug users (IDU) are at increased risk of human immunodeficiency virus (HIV) infection. Their HIV prevalence however varies from place to place and may not be directly linked with the level of individual risk. This study explores the relative importance of individual and community level characteristics in the practice of HIV-related risk behaviors in IDU in Hong Kong where the HIV prevalence has remained low at below 1%.

METHODS

Methadone clinics were used as the channel for accessing drug users in Hong Kong. HIV-related risk factors in drug users attending these clinics were retrieved from a questionnaire routinely administered to newly admitted and readmitted clients, and assessed using logistic regression and multilevel analyses.

RESULTS

Between 1999 and 2005, a total of 41,196 person-admissions were recorded by 20 methadone clinics. Male gender, older age and new admissions in bigger clinics located in districts with older median age were more likely to have engaged in HIV related risk behaviors including heroin injection, needle sharing, unprotected sex and having multiple sex partners (p < 0.05).

CONCLUSION

Multilevel analysis is a useful adjunct for determining the association between risk behaviors and both individual and community factors in IDUs, which can be demonstrated even in low HIV prevalence settings.

Regional differences in HIV prevalence among drug users in China: potential for future spread of HIV?

Background

Drug use and in particular injecting drug use has been at the forefront of the explosive spread of HIV in general populations in many countries in Asia. There is concern that also in China increased HIV incidence in drug users might spark off a generalized epidemic in the wider population. Close monitoring of HIV incidence and risk factors in drug users is therefore important to be able to target interventions effectively. Second generation surveillance was launched to assess HIV prevalence and risk behaviours jointly with the purpose of describing trends and predicting future developments. To assess whether these goals were fulfilled among drug users in China we provide an analysis of risk factors for HIV infection and of regional differences in HIV prevalence.

Methods

We analysed data collected in 2005 in 21 drug user second generation surveillance sentinel sites from 14 provinces in China. We used random effects logistic regression to test for risk factors for HIV infection and regional differences.

Results

The overall HIV-1 antibody prevalence was 5.4% (279/5128); 4.9% among injecting drug users (IDU) not sharing needles and 3.7% among non-injecting drug users. We found substantial heterogeneity among the surveillance sites with prevalence rates ranging between 0% and 54%. HIV status was strongly affected by the regional prevalence of HIV. Risk behaviours were highly prevalent in regions where HIV prevalence is still low. The distribution of duration of drug use in different sites indicated different stages of the drug use epidemics.

Conclusion

]Regional differences in HIV prevalence in China reflect different stages of the drug use and HIV epidemics rather than differences in risk behaviours. Therefore, outbreaks of HIV among drug users in regions where prevalence is still low can be expected in the future. However, methodological limitations of surveillance embedded into routine systems limit the usability of existing data. More standardized approaches to data collection in secondary generation HIV surveillance are necessary to better understand regional differences in risk behaviour and prevalence and to design targeted intervention for those regions at risk of experiencing outbreaks.

Genetic characterization of HIV-1 strains circulating in Kazakhstan

To determine the HIV-1 genetic diversity in Kazakhstan, 85 blood samples from HIV-seropositive donors were collected between 2001 and 2003. The study population consisted of 91.8% injecting drug users (IDUs); the remainder was infected sexually or iatrogenically. A genomic region that included part of the polymerase gene was sequenced for all 85 samples, and from these, 6 samples were randomly selected for nearly full genome sequencing. Subtype A was the most common genetic form (94.1%), followed by CRF02_AG (4.7%) and subtype C (1.2%). All subtype A sequences clustered closely with samples from countries of the former Soviet Union (FSU). From these sequences, 47 (58.8%) presented the secondary protease inhibitor mutation V77I that has been linked to a genetic lineage in the FSU epidemic. In addition, most had the other 2 mutations that characterize the "V77I haplotype." All 6 nearly full-length sequences were subtype A and clustered with other FSU strains. The CRF02_AG strains from this population clustered with strains from Uzbekistan, reflecting the spread of the CRF02_AG epidemic in Central Asia. The HIV epidemic in Kazakhstan is predominantly in IDUs and is indigenous to the geographic region, and most of the strains are genetically similar to those circulating in the FSU and other parts of Central Asia.