What is Hepatitis C?
Hepatitis C is a virus.
The hepatitis C virus is one of several viruses that can cause inflammation of the liver.
Hepatitis C infection involves an initial acute phase of infection that may not be noticeable, because in most cases people do not feel sick. This phase can last up to six months, levels of the virus in the blood rise dramatically until the body’s immune system starts to produce antibodies. Antibodies are made in response to the presence of the hepatitis C virus.
For most people, hepatitis C is a slow acting virus and is a chronic illness that can be managed with a variety of strategies. The impact of hepatitis C and how severe it is will vary over time and will be different for each person. Generally, the statistics show that the damage caused by the virus will increase as time goes on and will have a matching impact on the liver. However, this will not apply to everyone.
It is estimated that approximately 74,200 Victorians and around 284,000 people Australia-wide have been infected with the hepatitis C virus. Of these, around 211,000 have developed chronic hepatitis C. Within Australia’s Indigenous community, around 22,000 have been exposed to the virus while 16,000 have developed chronic hepatitis C. Of the 30,000 - 35,000 people held in prisons, 9,000 - 14,000 has been exposed to hepatitis C while 7,000 to 11,000 have chronic hepatitis C.
Chronic Hepatitis C
On average, around 25% of people who contract hepatitis C will clear the virus naturally within the first 12 months. For the remaining 75% of people the virus is not eliminated. For these people the virus will probably remain in their body for the rest of their lives. This is called chronic (long term) hepatitis C.
Of 100 people with chronic hepatitis C who have remained untreated after 20 years, 45 people may not develop any liver damage;31 may develop mild to moderate liver damage;7 may develop cirrhosis of the liver and 1 may develop liver failure. After 40 years, 45 people may not develop any liver damage; 31 may develop mild to moderate liver damage; 20 may develop cirrhosis of the liver and 4 may develop liver failure.
When the virus is multiplying in the liver, it can mutate and change its outer protein coat so that antibodies don’t recognise it easily. This may explain why the antibody response does not eliminate the virus in most cases. By the time antibodies are ready to attack the virus, it has already changed and the antibodies have no effect.
Some people may never experience any symptoms. The virus is slow acting and it can take many years from infection before any permanent damage to the liver (such as scarring) occurs. There is no way to predict how the virus will affect each individual or over what period of time liver damage may develop.
For most people, hepatitis C does not result in serious disease or death. However, factors such as the person’s gender, health history, diet, life situation, age when they were infected, stress levels, alcohol and drug intake (whether legal, prescribed or illicit), will all have an impact on how each person experiences hepatitis C.
Unlike antibodies to other diseases, such as hepatitis A, hepatitis C antibodies do not provide any immunity to hepatitis C. Even in those people who have been infected with hepatitis C once and cleared the virus, re-infection can still occur.
There are several different strains of the hepatitis C virus called ‘genotypes.’ These strains are slightly different in their genetic make-up, but similar enough to still be labelled hepatitis C. It is currently believed that there are at least 6 different genotypes of hepatitis C here in Australia, which are numbered 1, 2, 3, and so on. There are also subgroups within each genotype, which are further differentiated 1a, 1b, etc. The most common genotypes found in Australia are 1 and 3.
Studies have shown that it is possible to be infected with multiple hepatitis C genotypes. To prevent re-infection with a different genotype, it is important to practise the same blood awareness precautions as for preventing an initial infection. CLICK HERE to view the Hepatitis C Prevention page.
At this stage, there appears to be no evidence of any relationship between genotype and severity of liver disease.
However, genotype is the most significant predictor of response to antiviral treatment.