ABSTRACT
BACKGROUND: Korea is an endemic area of viral hepatitis B with a rate of 5~10% carrier state. Therefore, hepatitis B vaccination is performed nationwide. But 5~15% of healthy individuals fail to respond adequately to the vaccine and an approved guideline for the nonresponders has not been developed yet. This study is designed to identify risk factors for those who lack anti-HBs after hepatitis B vaccination and to document the results of a double-dose revaccination in such nonresponders to the primary vaccination. METHODS: From Feb. 1996 to Aug, 1997, we assessed 51 healthy subjects(HBs Ag negative, anti-HBs negative, anti-HBc negative and a normal LFT). All subjects were vaccinated with Hepavax- B, 1.0ml, 24 by a rapid schedule(0, 1, and 2 months) and 27 by a standard schedule(0, 1, and 6 months). Anti-HBs titers were evaluated 3 months after the third vaccine and assessed the nonre-sponders (anti-HBs titer<2mIu/ml) and the hyporesponders(2~10mK/ml). All 13 nonresponders were revaccinated with 2ml of Hepavax-B 3 months after the primary vaccination. Anti-HBs titers were evaluated 1 month later. RESULTS: The differences in age(p<0.01) and smoking amount(p<0.05) between the responders and the hypo and the nonresponders were statistically significant. There were more males and higher body mass index in the hypo and the nonresponders but not statistically significant. The seroconversion rate after the double-dose vaccination was 92.3%(12/13) with an average titer of 5K08mlU/ ml(1-132.4mIU/ml). CONCLUSIONS: Increase in age and smoking amount were the risk factors of the nonresponders after the primary vaccination. Most of the hypo and the nonresponders to the primary vaccination responded adequately to the double-dose revaccination.