Clincial and edidemiological studies on hepatitis B in children.

Sera from children with various clinical categories of hepatitis were examined for hepatitis B surface (HBs) antigen (Ag) by radiommunoassay and for antibody to HBsAg (anti-HBs) by the passive hemagglutination test. It was found that frequencies of HBsAg and anti-HBs in 56 cases of acute hepatitis were 55% (31/56) and 11% (6/56), respectively. All of 4 patients with chronic hepatitis were found to have persistent HBs antigenemia. As for hepatitis in infant under the age of 6 months HBs Ag was detected in 2 each of 31 cases of neonatal hepatitis and of 15 cases of anicteric hepatitis. The data suggest the importance of HB virus as an etiologic agent of acute and chronic hepatitis in children in this country, however, other agents were supposed to be responsible for hepatitis in early infancy. Anti-HBs Ab was first detected in 15% of a group of children age from 3 to 5 years in Rishiri Island and in 12% of children aged from 6 to 9 years in Sapporo City. Frequency increased gradually through school age in both areas. Thus, HB virus infection seems to be common in the childhood population in urban as well as rural area of Hokkaido district.