Hepatitis B (HBV) is a liver infection caused by the hepatitis B virus. Most people who get the disease recover from it and can never get it again. However, about 10% of adults who get hepatitis B will go on to have chronic (long-term) infection and can pass it on to others (be a carrier). When it is chronic, it can be a serious disease that can lead to cirrhosis (scarring of the liver) and/or liver cancer. The younger a person is when infected, the more likely he or she is to go on to have chronic infection and to develop serious liver disease. There is a vaccine to prevent hepatitis B infection.