The 5-7% of adults in the United States with severe mental illness (SMI), especially the 50% who are 'dually diagnosed' with co-occurring substance use disorders (SUD), are at an elevated risk of HIV and hepatitis C virus (HCV). However, little is known about HIV/HCV co-infection in this population. This paper examines the prevalence and correlates of HIV, hepatitis C, and HIV/HCV co-infection in a large, multisite sample of SMI clients.

The study conducted a re-analysis of data on prevalence and correlates of blood-borne infections in a multisite sample of SMI clients. In 1997-1998, 755 SMI clients were tested for HIV, hepatitis B virus and HCV, and assessed for demographic, illness-related and other behavioral risk factors for blood-borne infections. The prevalence and correlates of co-infection were examined, as well as the knowledge, attitudes and risk behaviors of individuals with HCV mono-infection.

Of the 755 participants, 623 (82.5%) were negative for both HIV and HCV, 23 (3.0%) were positive for HIV, 109 (14.4%) were positive for HCV, and 13 (1.7%) were co-infected with HIV and HCV. Overall, 2.5% of dually diagnosed participants were co-infected, whereas only 0.6% of SMI participants without a comorbid SUD diagnosis were co-infected. Co-infection was associated with psychiatric illness severity, ongoing drug abuse, poverty, homelessness, incarceration, urban residence and minority status. HCV-mono-infected clients continued to engage in high levels of risk behavior for HIV. CONCLUSION:: In addition to efforts to identify and treat SMI patients with HIV/HCV co-infection, HCV-mono-infected clients should be targeted for prevention interventions.