Epidemiology

HCV is transmitted by the parenteral route, with most new infections reported in injecting drug users. People with haemophilia were at high risk of HCV infection until universal screening of blood products in 1990: HCV transmission from HCV-infected blood products has affected significant numbers of people with haemophilia, although new HCV infections via this route are rarely reported. HCV is transmitted perinatally, and co-infection with HIV increases the likelihood of HCV vertical transmission. HCV transmission via heterosexual intercourse is uncommon.  However, sexual transmission has been increasingly recognised among men who have sex with men (MSM), especially in association with HIV co-infection.^5,6 Although rates of HIV infection are low among Australian injecting drug users, the prevalence of HCV infection is high, such that injecting drug users with HIV infection are likely to have HCV co-infection.⁷ HCV co-infection was present in 7.6% of people with HIV infection at one Australian tertiary referral centre.⁸ In Australia, HCV infection is more prevalent among MSM than in the general population. One study from Sydney reported an HCV prevalence of 7.6% in MSM,⁹ with an association between HCV infection and both injecting drug use and HIV infection. The prevalence of HCV co-infection in people undergoing cART in the Australian HIV Observational Database was approximately 12%.¹⁰