The incidence of hepatitis B virus infection has gradually decreased since 1983 when hepatitis B vaccine was firstly produced. This study was performed to evaluate the efficacy of hepatitis B immunization.

The elementary, middle and high school children in Incheon area were enrolled in this study in 1997 and 1998. Hepatitis B virus surface antigen(HBsAg) was measured using reversed passive hemagglutination(RPHA).

The results were as follows The positive rates of HBsAg in elementary, middle and high school children were 0.7%(337/46,861), 2.5%(381/15,026) and 3.1%(681/21,938) respectively in 1997 and 0.6%(257/41,946), 2.7%(379/13,652) and 2.4%(628/25,277) respectively in 1998. The positive rates of HBsAg in children under 19 years of age in 1985, 1990 and 1995 were 6.1, 5.2 and 3.5% respectively.

The positive rates of HBsAg in elementary school children in 1997 and 1998 has decreased compared with those of the previous studies. The majority of elementary school children were given hepatitis B vaccination. These results suggest that hepatitis B vaccines used in Korea were effective for prevention of hepatitis B infection in school children.