Hepatitis B is a serious liver infection caused by the hepatitis B virus (HBV). For some people, hepatitis B infection becomes chronic, meaning it lasts more than six months. Having chronic hepatitis B increases your risk of developing liver failure, liver cancer or cirrhosis — a condition that permanently scars of the liver.

Most adults with hepatitis B recover fully, even if their signs and symptoms are severe. Infants and children are more likely to develop a chronic (long-lasting) hepatitis B infection. A vaccine can prevent hepatitis B, but there’s no cure if you have the condition. If you’re infected, taking certain precautions can help prevent spreading the virus to others.