About Hepatitis C – some background
Hepatitis C is a blood-borne virus that predominantly infects the cells of the liver. This can result in inflammation and significant damage to the liver. It can also affect the liver’s ability to perform its essential functions. Although it has always been regarded as a liver disease - ‘hepatitis’ means ‘inflammation of the liver’ - recent research has shown that the hepatitis C virus (HCV) affects a number of other areas of the body. These can include the digestive system, the lymphatic system, the immune system and the brain.
Hepatitis C was first discovered in the 1980s when it became apparent that there was a new virus causing liver damage. Before being properly identified in 1989 it was originally known as non-A non-B hepatitis. In 1991 a screening test was developed making it possible to detect HCV in blood samples. As a relatively new disease there are still many aspects of hepatitis C, which are yet to be fully understood.
Hepatitis C is an RNA virus. RNA viruses mutate much more than DNA viruses. This ability to mutate makes the RNA virus much harder for the body’s immune system to locate and destroy it. In hepatitis C there are 6 major variations of the virus, labelled 1 to 6. These are known as ‘genotypes’. Different genotypes predominate in different parts of the world. One genotype cannot change into another. However, it is possible, although rare, to be infected with more than one genotype at the same time.
A hepatitis C infection can be categorised into two stages. The first stage is acute infection (following initial infection). The second stage is chronic infection. The acute stage refers to the first 6 months of infection and does not necessarily result in any noticeable symptoms. Approximately 20% of those infected with hepatitis C will naturally clear the virus from their body within the first six months. For the remaining 80% a chronic (long-term) infection will develop.
Chronic hepatitis C
The course of a chronic hepatitis C infection is extremely varied and unpredictable. Some people experience very few symptoms for as long as a decade. Others can suffer symptoms almost from the start. Some will progress to develop fibrosis and cirrhosis (scarring) of the liver, liver cancer or end stage liver disease, while others experience very little liver damage, even after many years. In cases where there is an absence of symptoms many people do not discover that they have HCV until some time after they have been infected.
Another reason that hepatitis C goes undiagnosed for many years is that its symptoms can often be put down to other illnesses. For example, depression, fatigue, skin problems, insomnia, pain and digestive disorders could all have other causes. For these reasons hepatitis C is often referred to as the ‘Silent Epidemic’.
HCV world prevalence
There are an estimated 150 million people worldwide chronically infected with hepatitis C. The level of infection, known as prevalence, varies widely from country to country (0.5%-15.0%). The virus can only be transmitted by infected blood.
Epidemiology and burden in EU
In 2013, 32 512 cases of hepatitis C were reported in 26 EU/ EEA Member States, a crude rate of 9.9 per 100 000 population. Of cases reported in 2013, 608 (1.9%) were reported as ‘acute’, 5736 (17.6%) as ‘chronic’, 23 230 (71.5%) as ‘unknown’ and 2 938 cases (9.0%) were not classified due to incompatible data format. The interpretation of hepatitis C data across countries is hampered by differences in surveillance systems and difficulties in defining the cases as acute or chronic. In addition, surveillance of hepatitis C which is largely asymptomatic until a late stage is challenging with reported notifications reflecting testing practices rather than true occurrence of disease.
Drug treatment to eradicate the virus has advanced greatly in the last few years. All oral regimens with excellent safety profile and short duration of treatment (3-6 months) have been developed are effective up to 100% of treated patients. The existence of highly accurate diagnostic methods and highly effective treatments provide reasonable hopes for HCV elimination in the next 15-20 years.