Background
: Korea is an endemic area of viral hepatitis B, and the hepatitis B vaccine has been made and broadly prescibed since last decade. There have been a lof of studies and arguments to select proper indications, injection times, and interval for boaster injections. Among those, there have been arguments that it is better to test not only HBs antigen and anti-HBs, but also anti-HBc is more susceptible to viral hepatitis B and should be vaccinated. Previous studies have shown high rate of anti-HBs formation among only anti-HBc positive persons after three injections of hepatitis B vaccine. In this sutdy, authours selected persons with only anti-HBc positive, vaccinated once to the case group and compared the anti-HBs formation rate and titer ar more than 6 months after vaccination among the case and control groups.

Methods : Among the patients visited Department of Family Medicine in Kyung Hee Medical Center, we selected persons with no history of jaundice, hepatitis, blood transfusion, or heptitis B vaccination with normal AST, ALT and ALP level, and with only anti-HBc positive viral marker. The selected persons were divided by their opinion into case and control group. After then hepatitis B vaccine was injected to the case group and no vaccine was injected to the control group. More than six months later, the rate of anti-HBs formation, the titer of anti-HBs and the liver function test were checked and compared among the two groups.

Results : The anti-HBs formation rate in the case group was 68%(17 of 25 persons), and the rate in the control group was 9.5%(2 of 21 persons). So the former was significantly higher than the latter(P<0.01). Among the case group, the rate of nonresponder was 32%, low responder was 24%, intermediate responder was 28%, and high responder(anamnestic response) was 16%. There were no cases showing the positive conversion of HBsAg, the negative conversion of anti-HBc, or abnormal liver function test.

Conclusion : The persons with only anti-HBc positive viral marker with normal liver function were higher rate of anti-HBs formation in case gorup comparing to the control group after one hepatitis B vaccination, and so, they should be vaccinated with hepatitis B vaccine. The vaccination schedule for this group is to vaccination once and evaluate the titer of anti-HBs. If the anti-HBs titer shows anamnestic response, no more vaccination is needed and if the anti-HBs titer dosen't show anamnestic response, vaccination should be continued as usual schedule. But considering the cost-effectiveness, it would be better to vaccinate three times without the evaluation of anti-HBs titer.