RISK-FACTORS FOR HEPATITIS-C VIRUS-INFECTION AMONG INJECTING DRUG-USERS IN SYDNEY

Objective-To study risk factors for hepatitis C virus (HCV) infection in injecting drug users (IDUs) from central Sydney. Setting and subjec ts-All IDUs attending a primary health care facility in central Sydney between December 1991 and November 1992 who underwent HCV antibody te sting. Methods-Information was obtained retrospectively from client fo rms routinely completed at the time of medical consultation. Additiona l information on injecting history and practice was obtained from the registration forms of subjects who also attended the needle syringe ex change programme at the same health care facility. Results-Of the 201 IDUs tested, 118 (59%) had HCV antibodies, which did not differ signif icantly between males and females. HCV prevalence increased significan tly with age, being highest in IDUs who were aged 35 years or more (93 %) and lowest in IDUs aged under 20 years (17%). HCV prevalence increa sed significantly with time since first injecting, from 26% for IDUs w ho had injected for less than 3 years to 94% for those who had injecte d for more than 10 years. HCV prevalence was also significantly higher in heterosexual IDUs as compared with homosexual male IDUs, and in op iate users as compared with stimulant users, even after adjustment for age and duration of injecting. HCV prevalence was strongly associated with exposure to hepatitis B virus, but was not associated with expos ure to HIV. Conclusion-Recent HCV transmission indicates ongoing injec ting risk behaviour despite HIV prevention efforts, and underlies the potential for increased transmission of HIV through the sharing of inj ecting equipment. Within the population of IDUs, those who are heteros exual or inject heroin appear to be at increased risk of HCV infection .