David Iser
Gastroenterologist, St Vincent’s Hospital, Melbourne

Andrew Chan
Hepatology Fellow, Austin Health

Chronic Hepatitis C virus (HCV) infection is a major cause of chronic liver disease and an important public health concern in Australia. Around 25% of acute HCV infections will clear spontaneously within 6 months; however, the remaining 75% will progress to chronic disease and are at risk of progressive liver fibrosis leading to cirrhosis, liver failure, and hepatocellular carcinoma (HCC). Spontaneous clearance is often more common in younger people and females¹. Chronic HCV infection can lead to the development of liver cirrhosis usually after 20-30 years of active infection. Progression is more rapid in people with significantly abnormal serum alanine aminotransferase (ALT) levels, older population groups at the time of acquisition², and in people with cofactors for liver disease, such as alcohol misuse disorder; metabolic risk factors for metabolic dysfunction-associated steatosis liver disease (MASLD); and concurrent HIV and/or hepatitis B virus (HBV). Metabolic risk factors for MASLD include obesity, type 2 diabetes, hypertension, and dyslipidaemia. This has led to the World Health Organisation (WHO) setting a global target of HCV elimination by 2030³.

HCV is transmitted via the parenteral route, with the majority of new infections reported in people who inject drugs (PWID). People with haemophilia were previously considered at high risk of HCV transmission from receiving HCV-infected blood products. However, with the advent of better universal screening of blood products since 1990, new HCV infections from blood products are now considered rare. HCV can also be transmitted perinatally, and concurrent HIV in the mother increases the likelihood of HCV vertical transmission. HCV transmission via heterosexual intercourse is uncommon, but increased sexual (permucosal) transmission is recognised among men who have sex with men (MSM), especially in association with HIV^4,5. Although the rate of HIV is low among Australian PWID, the prevalence of HCV infection is still high, such that PWID with HIV should be screened for likely concurrent HCV⁶. There is an associated increased rate of progressing to cirrhosis, increased risk of HCC, and mortality in people with HCV in the setting of HIV. The estimated incidence of HCV-HIV coinfection in Australia was reported to be 0.2 per 100 person-years in 2022⁷.

In Australia, since the early 1990s, the diagnosis of HCV infection requires a mandatory notification. In 2022, there were 6,728 HCV notifications in Australia, with 68% of the notifications being among males⁷. The number of HCV notifications in Australia has declined since 2016 after the listing of subsidised interferon-free direct-acting antiviral (DAA) therapy on the Pharmaceutical Benefits Scheme (PBS) in March 2016. In 2022, 5,210 people received DAA treatment through the PBS, and between the beginning of 2015 to the end of 2022, a total of 104,110 people received PBS-subsidised DAA treatment⁷. At the end of 2022, it was estimated that there were 74,400 people living with chronic HCV. This has declined from the estimated total of 117,814 people at the end of 2020⁷ and is related to the availability of PBS-subsidised DAA treatment, reduction in the prevalence of injecting drug use, and improved harm reduction measures (e.g., needle and syringe programs and opioid substitution treatment uptake) among at-risk populations, such as PWID. The at-risk group and highly marginalised population, such as PWID, Aboriginal and Torres Strait Islander peoples, those in rural and remote settings, and the prison population, remains particularly challenging in seeing effective engagement in treatment uptake. Models of care for the treatment of HCV infection in Australia have now taken on a multidisciplinary initiative, with specialist gastroenterologists, hepatologists, or infectious diseases physicians, general practitioners, or authorised nurse practitioners all eligible to prescribe DAA treatment under the PBS. This facilitates more timely, affordable, and equitable access to DAA treatment within Australia.

Several position statements and guidelines from major gastroenterology societies such as the European Association for the Study of the Liver (EASL), the American Association for the Study of Liver Diseases (AASLD), and the Gastroenterological Society of Australia (GESA) have been published and made available. This chapter has been formulated by referencing these international guidance statements and forms the basis of our recommendations for the treatment of HCV infection, with the aim to meet the set target of global elimination by 2030.