Abstract
In 1986, the Japanese government initiated a nationwide hepatitis B immunization program for infants born to HBV carrier mothers. We evaluated the long-term protective efficacy of this program. Total 105 children were vaccinated according to the schedule and we followed the levels of their serum HBs antibodies for over 4 years. Levels of their serum HBs antibodies were significantly declined at the age of 7 and older. But nobody showed evidence of HBV infection in this study period. This phenomenon is similar to those of other countries where universal vaccination have already been launched. In conclusion, long-term effectiveness of national vaccination program for mother to infant HBV infection is satisfactory and booster vaccination seems to be unnecessary at least until13 years old.
