SEROEPIDEMIOLOGY ON HEPATITIS B VIRUS IN ELEMENTARY SCHOOL STUDENTS COHORT IN GYONGGI PROVINCE, KOREA

Abstract

Chronic liver disease and hepatoma from Hepatitis B virus (HBV) infections are major sources of morbidity and mortality in Korea. To estimate the incidence and changing pattern of the prevalence of HBV, we carried out follow-up studies from 1999 to 2001 with 921 paired students. We also compared the prevalence of HBV between 1993, 1999 and 2001. Enzyme immunoassay was used for serology of HBV. During 1999 to 2001, the incidences of HBV among elementary school students are as follows: among susceptible subjects (all 3 markers were negative), HBsAg conversion rate, 1.3%; Anti-HBc conversion rate, 3.5%; and Anti-HBs conversion rate without vaccination history, 21.0%. Infection rate was 24%. The results of multiple logistic regression analysis demonstrate rural area and family history of hepatitis B were significantly related on Anti-HBs positive (OR = 1.4, and 1.6, respectively). Urban area was the significant risk factor for susceptibility. Age, gender and area-adjusted prevalence rate of Anti-HBs was 81.3%, 71.0% and 67.4% in 1993, 1999, and 2001 respectively. The rate of susceptibility increased continuously: 15.7%, 26.6% and 30.3% in 1993, 1999, and 2001 respectively. Positive rates of HBsAg and Anti-HBc decreased: 3.4% to 2.7% and 9.6% to 6.5% respectively. Among the students who had negative Anti-HBs and HBV vaccination history, the conversion rate of HBsAg or Anti-HBc was 5.8%. Therefore, further research on the susceptibility of Anti-HBs negative people who have the HBV vaccination history should be carried out. Booster vaccination of HBV also should be considered for the people who have negative Anti-HBs.