Risk factors for HIV infection in injection drug users and evidence for onward transmission of HIV to their sexual partners in Chennai, India

OBJECTIVES: Determining HIV prevalence in injection drug users (IDUs) and their regular sex partners in Chennai, India. METHODS: A total of 226 IDUs and their regular sex partners were enrolled during April-July 2003. After informed consent was obtained, a semistructured questionnaire was administered and serum was tested for HIV antibody. RESULTS: The HIV seroprevalence was 30% (68/226) in IDUs and 5% in their regular sex partners (11/226). While in 25% of couples only the male partner was HIV positive, 5% of the couples were concordant for HIV infection and 70% were HIV negative. Fifty-seven percent of the HIV-positive IDUs and 45% of the HIV-infected women thought that they had "no chance" or "very little chance" of getting HIV, reflecting low HIV risk perception. More than 20% IDUs reported borrowing or lending of injection equipment. In univariate analyses "sex" and "condom use" with sex workers had no bearing but "more than twice a day injecting frequency," "history of incarceration," "tattoos," "recruitment from northern part of the city," and ever-injecting drugs in drug-selling places had significant association with HIV infection in IDUs. In an adjusted model, the odds of HIV infection were 2 times higher among IDUs who had ever injected drugs in drug-selling places and 6 times higher in those who were recruited from the northern part of central Chennai. CONCLUSION: Reducing sharing of injection equipment and unsafe tattooing through targeted and environmental interventions, increasing HIV risk perception, and promoting safer sex practices among IDUs and their sex partners are urgent program needs.