RISK OF HEPATITIS-B VIRUS TRANSMISSION BY HIGHLY VIREMIC CHRONIC CARRIERS IN SCHOOL

To determine the frequency of hepatitis B virus (HBV) transmission by hepatitis B surface antigen (HBsAg) carriers in school classes 44 high ly viremic children were examined over an average period of 5 years. A ll these HBsAg carriers had been infected with the virus in a hospital endemia during treatment for childhood malignancies. They have been c ontinously positive for HBeAg with very high HBV-DNA titers of more th an 10(8) viral genomes/ml serum. Due to data protection reasons no ser ologic tests could be done in these school classes. Therefore, the pat ients and their parents were asked to fill in a questionnaire about an y cases of hepatitis in the school classes during the study period. Th ese results were compared with the hepatitis B registrations in the re cords of the public health offices. No differences were found between the two sources of data. In the school classes of the HBsAg carriers t he incidence of hepatitis cases was 0.3 per 1000 pupils per year, whic h is not different from the hepatitis B morbidity within the general p opulation. Therefore, there is no reason to impose any restrictions on HBsAg carriers in school. In contrast, several cases of HBV transmiss ions occured to non-vaccinated family members of the HBV carriers.