Epidemiological Study on Hepatitis B Virus infection in Taiwan

The determination of hepatitis B surface antigen (HBsAg), its antibody (anti-HBs) and antibody to hepatitis B core antigen (anti-HBc) were performed on sera from 1,354 healthy persons aged 0 to over 70 years and 36 cord blood specimens using radioimmunoassay. The positive rate of HBsAg was 14.6% accompanied with positive rate of anti-HBc in 16.6% but anti-HBs in only 4.2% between 0-1 year of age. Then the positive rates of both HBsAg and anti-HBc went u to 35.7% between 2-4 years of age. Thereafter the positive rate of anti-HBc continued to increase steadily up to over 88% after 40 years of age. On the contrary, the positive rate of HBsAg dropped to 20.0% between 5-9 years of age, then remained to be over 17% before 40 years of age and thereafter decreased gradztally down to 8.6% in the eighth decade. After 10-14 years of age, the differences of positive rates between anti-HBc and anti-HBs by age nearly equal to the positive rates of HBsAg in every age group. In Taiwan, the number of HBsAg carriers is estimated to be 2.9 millions. The hepatitis B e antigen (HBeAg)-positive rate in 296 asymptomatic carriers of HBsAg was as high as 31.1% with very high rate of 74.4% and 69.5% in the first and second decades respectively. Among 761 pregnant women HBsAg was positive in 16.7%, and among 85 cases out of those HBsAg-positives HBeAg was positive in 42.3%; the high prevalence rate of HBsAg-and HBeAg-positives in pregnant women is the most important contributing factor of the high carrier rate of HBsAg in Chinese.