Background: HIV is predominantly heterosexually transmitted in India except for the North East regions. There is little information available on the HIV epidemic among injecting drug users (IDUs) in the South. This study estimates the incidence, prevalence and risk factors for HIV among IDUs in Chennai, India and estimates the prevalence of co-infection with HBV and HCV in our cohort.

Methods: IDUs from different regions of Chennai were actively recruited for screening for a longitudinal study after obtaining their informed consent. The study participants received risk reduction counseling at baseline and every six months thereafter. At the time of this abstract, 399 IDUs were screened and their test results and behavioral data were available for analyses. Incidence was calculated using the Calypte HV-1 BED Incidence EIA. Univariate and multivariate logistic regression were used to identify risk factors. A p-value <0.05 was considered statistically significant.

Results: All the participants were male. 96.7% were Tamil and 50.9% were married. The mean age was 35.3 years. 21.6% had never received any education. The prevalence of HIV, HBV and HCV were 35.6%, 11.3% and 75.9% respectively. Of those infected with HIV, 85.2% were co-infected with HCV and 12% were infected with HIV, HBV and HCV. The annualized incidence among this cohort was estimated to be 4.53 (95% CI: 0.56, 8.5) using the detuned assay. In univariate analyses, HCV status, marital status, income, years of use, alcohol intake, brown sugar or buprenorphine use, sharing needles with HIV positive users, injecting at the dealers place, frequency of daily use, injecting alone or with people whom they know well, sexual behavior and history of tattoo were all significantly associated with the individuals HIV status. In the multivariate analyses, HCV status, years of use, income, alcohol intake and sexual behavior remained significantly associated.

Conclusions: Based on these results, it is evident that the HIV epidemic is rampant among IDUs in Chennai. Interventions have to be set in place to check the further spread of this epidemic among IDUs and from them to their families. The high rates of co-infection coupled with the poor socio economic and educational status will make management of HIV even more complicated.