About Hepatitis C
The hepatitis C virus is a member of the flavivirus family of ribonucleic acid (RNA) viruses. The virus reproduces by making many copies of itself in liver cells.
The hepatitis C virus does not kill liver cells directly, but the immune response initiated by the presence of the virus in the liver can cause liver inflammation and cell death. (Farrell, G.C. 2002)
There are six main genotypes (strains) of hepatitis C. Each genotype contains numerous subtypes, labelled a, b, or c. Genotypes 1a and 1b (54% prevalence) and 3a (37% prevalence) are the most common genotypes in Australia. (McCaw, R., et al. 1997)
Hepatitis C was discovered by scientists in 1988 and found to be responsible for most of the cases of ‘non-A, non-B hepatitis’. Early studies confirmed that hepatitis C was spread through blood-to-blood contact. An accurate test to diagnose hepatitis C became available in Australia in 1990. The test detected antibodies produced in reaction to the hepatitis C virus.
It is estimated that 130-150 million people worldwide are chronically infected with hepatitis C. (WHO Hepatitis C Fact Sheet)
In Australia, it is estimated that 230,470 are living with chronic hepatitis C. (Kirby Institute, Annual Surveillance Report (ASR) 2015 - p12)
The estimated number of new cases diagnosed of hepatitis C infection has declined from 16,000 in 2001 to 10,261 in 2011. The majority of these had
hepatitis C for some time.
In 2011, 80% of newly acquired hepatitis C infections (within that last two year) were identified as having resulted from unsafe injecting drug use. The number of new infections where the exposure category was undetermined increased to 106 from 75 in 2010. The remaining people with hepatitis C were infected in other ways, including:
- unsterile tattooing or body piercing procedures
- unsterile medical procedures or vaccinations (particularly in countries with high rates of hepatitis C)
- needle-stick injuries and accidental exposure to infected blood or blood products
- exposure to blood in the home
- some other form of blood-to-blood contact.
Some people with hepatitis C cannot identify how they were infected.
Farrell, G. C. (2002). Hepatitis C, other liver disorders, and liver health: A practical guide. Sydney, Australia: MacLennan and Petty Pty Limited.
McCaw, R., Moaven, L. D., Locarnini, S. A. & Bowden, D. S. (1997). Hepatitis C virus genotypes in Australia. Journal of Viral Hepatitis, 4, 351–357.
The World Health Organisation (WHO) (2014). Hepatitis C Fact Sheet. Available from:http://www.who.int/mediacentre/factsheets/fs164/en/index.html. Accessed 15 July 2014.
The Kirby Institute (2012). HIV, viral hepatitis and sexually transmissible infections in Australia Annual Surveillance Report 2012. The Kirby Institute, The University of New South Wales, Sydney, NSW. Available from: http://www.kirby.unsw.edu.au/surveillance/2012-annual-surveillance-report-hiv-viral-hepatitis-stis. Accessed 17 October 2012.
National Centre in HIV Epidemiology and Clinical Research (NCHECR) (2010). ‘Estimates and projections of the hepatitis C virus epidemic in Australia’.
Poynard, T., Ratziu, V., Charlotte, F., Goodman, Z., McHutchison, J. G. & Albrecht, J. (2001). Rates and risk factors of liver fibrosis progression in patients with chronic hepatitis C. Journal of Hepatology, 34(5), 730–739