A 5 year old boy is detected to be HBsAg positive on two separate occasions during a screening program for hepatitis B. He is otherwise asymptomatic. Child was given three doses of recombinant hepatitis B vaccine at the age of 1 year. His mother was treated for chronic hepatitis B infection around the same time. The next relevant step for further investigating the child would be to –

The child in question has received complete vaccination for Hepatitis B, is currently asymptomatic but has tested positive for HBsAg. The aim in avestigating the child further is to establish his immune status which can be best revealed by obtaining anti HBsAg levels. If the tests shows inadequate levels of anti-HBsAg it would indicate that the vaccine had failed to mount an adequate immune response. Such a child should consult a pediatric hepatologist. If the test shows adequate levels of anti-HBs Ag, the adequacy of vaccination is confirmed and as the child is asymptomatic no further intervention is required. Positivity of HBsAg indicates that the child is a carrier of the antigen. 'Vaccination does not effect the HBsAg carrier state.