An observational study of children immunised in infancy against hepatitis B virus, evaluating the persistence of immunity and the immune response to a scheduled booster dose of hepatitis B vaccine

The UK immunisation guidelines recommend that children immunised with an accelerated course of hepatitis B vaccine (i.e. vaccination at 0, 1, 2 and 12 months) receive an additional booster dose of vaccine in later childhood (usually at 3 1/2 years of age).  The primary objective of this study is to assess what proportion of these children have 'protective' concentrations (> 10mIU/ml) of hepatitis B specific antibodies before and after the booster dose of hepatitis B vaccine.