Hepatitis B is a serious liver infection caused by the hepatitis B virus (HBV). For some people, hepatitis B infection becomes chronic, leading to liver failure, liver cancer, or cirrhosis — a condition that causes permanent scarring of the liver.
Most people infected with hepatitis B as adults recover fully, even if their signs and symptoms are severe. Infants and children are much more likely to develop a chronic hepatitis B infection. Although no cure exists for hepatitis B, a vaccine can prevent the disease. If you're already infected, taking certain precautions can help prevent spreading HBV to others.