[Intra-familial transmission of HBV infection].

: We investigated 63 household contacts of 29 children positive for serologic markers of hepatitis B virus, in order to assess the intrafamiliar spread of HBV infection. 40 relatives of 15 children affected by chronic hepatitis B (Group I) and 23 relatives of 14 patients affected by hemophilia (Group II) were studied. HBV markers (HBsAg, anti-HBs, anti-HBc, HBeAg, anti-HBe) were tested in all the subjects by RIA. Positive markers were found in 39 (62%) of the subjects; the combined prevalence for all HBV markers was 75% in the Group I, and 39% in the Group II. The higher prevalence rate in Group I can be explained by the possible previous infection of another member of the family, whereas in Group II the child is almost surely the first infected subject. Besides, subjects of Group I have probably been in contact with HBV infected children a longer time, compared to subjects in Group II. Our data suggest that household contacts of children with HBV infection are at high risk and should therefore be immunized against HBV.