The 70% to 85% of individuals who do not manage to clear the virus spontaneously in the acute phase of infection are considered to be in the chronic phase of hepatitis C after six months of infection. This is when hepatitis C becomes a chronic or long-term infection. The diagnosis of chronic hepatitis C is confirmed when HCV antibody testing is positive and HCV RNA viral presence is detectable on at least two occasions over a six month period.
The intense battle that goes on inside the body during the acute stage between the virus and the immune system has been won by the virus. It is now highly unlikely that the virus can be cleared without treatment.
How the disease then progresses will vary significantly from person to person. In terms of liver damage some people infected will have minimal liver damage with no scarring after many years while a few people can progress to cirrhosis (extensive scarring of the liver) within less than ten years. On average it takes about twenty years for significant liver scarring to develop.
It is still a matter of debate whether chronic HCV infection inevitably leads to cirrhosis. At present it is thought that this is the case, but that for some people it may take at least 50 years or more. They may well die of other unrelated diseases or conditions before cirrhosis develops. The rate of progression of liver damage cannot be accurately determined by liver enzyme levels, viral load or by genotype tests.
Symptoms people experience as with liver damage vary dramatically. Some people will have few, if any, symptoms for many years, while for others the symptoms can be severely debilitating.
It was originally though that the virus only infected liver cells. However, recently it has become clear that HCV also infects parts of the immune system and some blood cells. This means that hepatitis C is not just a liver disease but is a systemic disease, in that it can affect other organs in the body.
HCV triggers damage to the liver firstly in the form of inflammation, which then leads to scarring or fibrosis of the liver. How the virus affects the functions of the liver is discussed in the section The Liver & hepatitis C.
