Hepatitis is an infection and inflammation of the liver. Hepatitis B is the most important strain in drug users. About 1 in 20 of those infected develop chronic disease with a high risk of cirrhosis and liver cancer. Hepatitis B virus is spread in the same way as HIV but is much more infectious and harder to kill. Preventive measures often involve safer drug use and safer sex practices, but effective vaccination is also available, though expensive. New treatments are being developed.