Objectives: To assess the prevalence of blood-borne viruses and associated risk factors among prison entrants at seven Australian prisons across four States.

Design: Consecutive cross-sectional design. Voluntary confidential testing of all prison entrants for serological markers of human immunodeficiency virus (HIV), hepatitis C (HCV) and hepatitis B (HBV) over 14 consecutive days in May 2004. Demographic data and data related to risks for blood-borne virus transmission, such as sexual activity, body piercing, tattooing, and injecting drug use, were collected.

Results: National prevalence for HIV was 1%, hepatitis B core antibody 20%, and hepatitis C antibody 34%. Fifty-nine per cent of participants had a history of injecting drug use. Among injecting drug users, the prevalence of HIV was 1%, hepatitis C antibody 56%, and hepatitis B core antibody 27%. Forty-one per cent of those screened reported a previous incarceration. In the multivariate model, Queensland and Western Australian (WA) prison entrants were significantly less likely to test positive to HCV than those in New South Wales (NSW). Amphetamine was the most commonly injected drug in Queensland, Tasmania and WA. In NSW, heroin was the most common drug injected. In the multivariate analysis a history of injecting drug use, being aged 30 years or more, and a prior incarceration were positively associated with hepatitis C infection. For hepatitis B core antibody, age over 30 years and a history of injecting drug use were associated with an increased risk.

Conclusions: The findings support the view that prisoner populations are vulnerable to blood-borne virus infection, particularly hepatitis B and C. Prisoner populations should be included in routine surveillance programs so as to provide a more representative picture of blood-borne virus epidemiology in Australia.