This study was conducted to assess the current(2003-2005) prevalence of anti-HBs and immunologic memory for Hepatitis B vaccine in children from the central area of Korea.

Subjects were chosen from children and adolescents who received tests for hepatitis B surface antigen(HBsAg) and anti-HBs at Dankook University Hospital from March 2003 to May 2005. Among these, antibodies to hepatitis B core antigen(IgG anti-HBc) were checked. A single booster vaccination was performed on children whose anti-HBs titers were under 10 mIU/mL. One month after booster vaccination we rechecked the anti-HBs titer.

A total of 3,277 subjects were tested for HBsAg/anti-HBs, and 1,913(58.4 percent) of them were positive for anti-HBs. Of these, 29 subjects(0.9 percent) were positive for HBsAg. Positive results for anti-HBs by age were 78.6 percent for 6-12 months of age, 62.7 percent for 1-3 years of age, 51.9 percent for 4-6 years of age, 49.5 percent for 7-12 years of age, 63.4 percent for 13-15 years of age and 72.2 percent for 16-18 years of age. The 80 subjects who were tested negative for HBsAg/anti-HBs received a single booster vaccine, 71 subjects were tested positive for antibodies. IgG anti-HBc titer was checked for 169 of the subjects, 5 subjects were positive.

In our study, a significant anamnestic response was observed in 88.8 percent of children. This is believed to be a result of the relatively long immunologic memory effect of the hepatitis B vaccination in children from the central area of Korea.