Hepatitis B is an infectious disease caused by the HBV virus that causes inflammation of the liver. Hepatitis B is spread through secretions and body fluids, including genital secretions, saliva, and blood. The initial infection with hepatitis B often goes unnoticed but can appear in its typical form through a fever, fatigue, muscle aches and joint pain, head pain or cramps, nausea, and jaundice, or yellowing of the skin. Most of the time, the infection disappears on its own, but hepatitis B can sometimes become chronic and lead to cirrhosis. The diagnosis is confirmed by a blood test. In cases of chronic hepatitis B, treatments exist but do not cure the disease and are there to improve symptoms and prevent progression to the complications; interferon is also used. There is a vaccine against hepatitis B, recommended for the entire population, but mandatory for some people, such as the medical staff.