HEPATITIS B IMMUNIZATION TODAY

Key words: Hepatitis B virus, Immunization

More than a million deaths occur annually from Hepatitis B (HB) associated cirrhosis and primary liver cancer. Most HB virus infections occur during childhood and HB vaccine is 80% to 95% effective in preventing the carrier state. Vaccination eliminates horizontal transmission in immunized cohorts. Because of the failure of the “highrisk- group” strategy in most industrialized country universal immunization is now recommended. Immunization to HB virus is considered to have occurred if concentration of anti-HB surface antibody greater than 10 mIU/ml develop. No significant difference in immune response exist between term and preterm infants. Response to HB vaccine is not highly dependent on timing of vaccine doses; modest alterations in timing of doses do not affect the response to the vaccine. Follow-up data suggest that most responders can be given a booster dose 10 years after completing the vaccination course without further assessment of their antibody status. Non response to vaccination is associated with age. In these situations repeated doses can be effective in immunization. HB vaccination is considered to be safe particularly in infants where no unexpected serious side effects have been reported.