Hepatitis B is an infectious disease caused by the hepatitis B virus (HBV) that affects the liver. It can cause both acute and chronic infections.
Those who are acutely infected with the virus may experience no symptoms or may develop a rapid onset of sickness with vomiting, yellowish skin, tiredness, dark urine and abdominal pain lasting a few weeks.
After the acute illness resolves, especially in young children it may convert to a chronic viral infection. Most of those with chronic disease have no symptoms; however, cirrhosis and liver cancer may eventually develop.