Alpha-interferons are known to be the first drugs in the US that have been approved for treating Chronic Hepatitis B. An Interferon treatment is usually recommended in the case of patients who have the "replicative disease" (a.k.a. HBeAg positive). About 40 percent of such patients will lose the HBeAg serum after 16 weeks of intense treatment with the Interferon-alpha drug. The loss of HBeAg can be correlated with a prognosis which is improved. A few patients who are treated (less than 10%) can even be cured by this. Patients who are treated with the Interferon-alpha drug should present clear evidence of an infection with the virus that causes this disorder. Furthermore, the presence of Chronic Hepatitis B surface antigen in the patient’s blood ought to be documented for about six months. The individuals should also detain virus replication evidence, which can be documented the presence in the patient’s blood of the hepatitis B e antigen. Ongoing liver inflammation may also be present. A biopsy of the liver must also be done before treatment. Patients who have severe and decompensated disease of the liver (for example encephalopathy, very high serum bilirubin, ascites, prolonged prothrombin time) must not be allowed to follow a treatment that implies the intake of the Alfa Interferon.