When the hepatitis C virus (HCV) enters a person’s bloodstream, it 'seeks
out' the way to the liver and penetrates the liver cells. Once there, it begins
to reproduce. The virus uses the liver cells to multiply, but does not harm it
directly. The immune system then detects the cells infected with the virus and
destroys them. The liver becomes inflamed, which is a sign that the liver cells
are being destroyed. This is an acute hepatitis C infection.
Not everyone exposed to HCV will contract the infection. This depends on the
amount of virus transmitted. The virus is most likely to be transmitted as a
result of exposure to blood. Any contact with infected blood should be avoided.
If
the immune system kills all the infected cells, and thus
clears the virus, this is described as spontaneous clearance. Between 20 and
50% of people who have the virus manage to overcome acute hepatitis C in this
way. Antibodies against the virus remain behind after the infection has been
cleared. Some studies have found higher likelihood of spontaneous clearance in
women, white people, people with hepatitis B virus co-infection, and those with
acute HCV infection symptoms (possibly because this indicates a stronger immune
response); and lower likelihood in men, black people, heavy alcohol users, and
those with HIV co-infection.1 2 3
However, in most people (up to 80%), hepatitis C becomes chronic. The
infection is described as chronic if the virus remains in the body for longer
than six months and the HCV RNA in the blood is still positive. In cases of
chronic hepatitis C, the immune system has not managed to detect and eliminate
all the infected cells completely. In chronic infection, the virus continues to
cause inflammation of the liver, which also leads to the destruction of healthy
cells. The long-lasting inflammation gradually leads to scarring of the liver
tissue.
In the final stages of hepatitis C, healthy liver tissue is largely replaced
by hardened scar tissue. This state is called cirrhosis.
Once hepatitis C has become chronic, medical treatment is the only possible
cure. However, as the processes described largely go unnoticed by the majority
of people with hepatitis C, it can often take years or even decades until hepatitis
C infection is diagnosed.
This long period of ‘silent’ infection is part of what makes chronic
hepatitis C such a threat to a person’s health. The acute phase often
progresses without any symptoms, or only non-specific symptoms occur. The
chronic phase is rarely accompanied by any definite symptoms.4
As it goes unnoticed by the person living with the virus, it can lead to liver
damage. Diagnosis often only happens late and by chance. By this point,
complications, such as fibrosis or cirrhosis of the liver, may have already
occurred. The extent of liver damage is a shock to many patients.