Intrafamilial clustering of hepatitis B virus (HBV) infection: study of 10 Saudi families.

In order to evaluate the extent of intrafamilial clustering of hepatitis B virus (HBV) infection, serological tests for evidence of HBV infection were performed on family members of 10 Saudi children who were found to be HBs Ag-positive. The overall prevalences of carriers (HBs Ag-positive) and exposure (presence of any HBV marker) in the 89 siblings were 17.9 and 34.8%, respectively. In siblings of families where the mother was a carrier, exposure to HBV (51.6%) was higher (chi 2 = 1.99, P = 0.15) than in siblings of families where only the father was a carrier (31.4%) and significantly higher (chi 2 = 5.24, P = 0.02) than in siblings of families where neither of the parents was a carrier but both had previous exposure to HBV infection (17.4%). Our data indicate that mainly horizontal and perhaps perinatal transmission could account for this relatively high level of intrafamilial clustering of HBV infection in Saudi families. These results are important for the development of a strategy for controlling HBV infection in Saudi Arabia and perhaps in similar HBV endemic areas.