Abstract

The positive rate for serum anti-Hbs was analized among 424 0f HA vaccinated and 2035 of non-vaccinated cases at the Yeungnam University Hospital, Computed Automated Med-screening Center. Most of them from Kyungbook province and they had the last HB vaccination in the periods of 3 to 42months prior to this study. The followings were obtained. 1. The positive rates for serum HBsAg were 0.7% in the vaccinees, 9.6% in the non-vaccinated and 8.0% in the whole cases. 2. The positive rates for serum ant-HBs were 66.3% in the vaccinees, 47.9% in the non-vaccinated and 51.6% in the whole cases. 3. The positive rates for serum anti-HBs were 51.4% in the cases with one time of vaccination and 68.6% in the cases with two times of vaccination. On the vasis of these findings the positive rate for serum anti-HBs among the vaccines was significantly higher than of non-vaccinated (P<0.05). The positive rate for serum anti-HBs shortly after vaccination was higher than that of present our study which was made relatively long period after vaccination. As the reason a natural decrease of the titers of the serum anti-HBs can be postulated as one of the contributing factors for the discrepancy. In order to keep to serum antibody of perfect protectivity against HBV, it may be better to check the serum anti-HBs just vaccination, follow up and take booster injection when it is needed.