Long-term persistence of immunity to hepatitis B after vaccination during infancy in a country where endemicity is low.

Background: The long-term response to hepatitis B vaccination during infancy has not been fully evaluated in countries where endemicity is low.

Methods: The present study was a serological investigation of immunity to hepatitis B during adolescence. In a cohort of children who were born to hepatitis B virus carrier mothers and who were vaccinated during infancy, evidence of past or current infection and the response to a single booster dose of vaccine were analyzed.