The group of viruses (hepatitis A, B, C, D and E) that cause acute and/or chronic infection and inflammation of the liver gives rise to a major public health problem globally.
Hepatitis B and C viruses are major causes of severe illness and death.
The global burden of disease due to acute hepatitis B and C and to cancer and cirrhosis of the liver is high (about 2.7% of all deaths) and is forecast to become a higher ranked cause of death over the next two decades.
An estimated 57% of cases of liver cirrhosis and 78% of cases of primary liver cancer result from hepatitis B or C virus infection.
An estimated two billion people worldwide have been infected with hepatitis B virus and more than 360 million have chronic (long-term) liver infections.
About 620 000 people die every year as a result of hepatitis B virus infection. A vaccine against hepatitis B has been available since 1982.
Some 150 million people are chronically infected with hepatitis C virus, and more than 350 000 people are estimated to die from hepatitis C-related liver diseases each year.
Vaccination is one of the strategies used to prevent hepatitis infection. Vaccines exist against hepatitis A and B.
Effective candidate vaccines for hepatitis E prevention exist. Some progress has been shown in developing candidate vaccines against hepatitis C.