Hepatitis B is caused by the infectious hepatitis B virus (HBV). HBV alone is estimated to have infected 400million people throughout the globe, making HBV one of the most common human pathogens. Infection of infants and young children with the hepatitis B virus represents an important health hazard, since the younger the age at which the infection is acquired the greater the predisposition to the carrier state, chronic liver disease and subsequent development of cirrhosis and hepatocellular carcinoma