Hepatitis C is an infection of the liver caused by the hepatitis C virus.
It can cause inflammation (swelling) and fibrosis (scarring) of the liver tissue, and sometimes significant liver damage.
Many people do not realise they have been infected with the virus, because they may not have any symptoms or they may have flu-like symptoms that are easily mistaken for another illness, such as flu.
You can become infected with hepatitis C if you come into contact with the blood or, less commonly, body fluids of an infected person (see below). Drug users sharing needles are at particular risk.
There is currently no vaccine to prevent hepatitis C. This is because the hepatitis C virus mutates (changes into a different strain) very easily, which makes it hard to make a vaccine, and the virus has different genotypes (genetic variants).
How do you become infected?
The hepatitis C virus is present in the blood and, to a much lesser extent, the saliva and semen or vaginal fluid of an infected person. It is particularly concentrated in the blood, so it is usually transmitted through blood-to-blood contact.
The most common way you can become infected is by sharing contaminated needles to inject drugs. See Causes for other ways it is spread.
How common is it?
It is estimated that about 200,000 to 500,000 people are infected with hepatitis C in England and Wales. Many people do not know they are infected.
Outlook
The course of hepatitis C is unpredictable.
About one in five people with hepatitis C will fight the infection and naturally clear it from their bodies within two to six months, experiencing no long-term effects.
Of the rest, some will remain well and never develop liver damage, but many will develop mild to moderate liver damage (with or without symptoms). Alcohol consumption is known to speed up the progression of liver damage. People infected with HIV also show a faster development of liver damage.
In a few people, their liver damage will progress to cirrhosis (severe scarring of the liver) over a period of 20-30 years. If you have cirrhosis, you have a greater risk of developing liver cancer.
Cirrhosis may also lead to liver failure - in which case a liver transplant may be the only option.
Treatment with interferon and ribavirin can clear the infection in approximately half of those who are infected, but there are significant side effects (see Treatment).
