Prevention of hepatitis B virus infection: from the past to the future.

About 3-5 % of the world's population is chronically infected by hepatitis B virus (HBV) and is at risk of developing liver cirrhosis or hepatocellular carcinoma. The risk of dying prematurely because of chronic HBV infection is higher in younger people. The current strategies to prevent HBV infection involve immunization (active and/or passive) and antiviral chemoprophylaxis. The vaccines available for active immunization, containing hepatitis B surface antigen, are safe and confer long-term immunity in most healthy subjects. Since the vaccination is unsatisfactory in some patients, e.g., those with chronic kidney disease, human immunodeficiency virus infection, type I diabetes mellitus, and celiac disease, new strategies of vaccination are required. The neonatal, infant, and adolescent routine program vaccination in about 180 countries has greatly decreased the disease burden. Passive immunization with specific HBV immunoglobulins is recommended after single acute exposure, in infants born to infected mothers, and in HBV-infected patients undergoing liver transplantation combined with nucleoside/nucleotide analogues (chemoprophylaxis). Chemoprophylaxis is also indicated in HBV carrier candidates for immunosuppressive treatment and in patients with occult B infection undergoing immunosuppressive therapy or hematopoietic stem cell transplantation. Since HBV is not eradicable by an immune response or by antiviral drugs developed so far, the only preventive strategy remains global neonatal vaccination in all countries, firstly in HBV-endemic countries.