Intra-familial evidence of horizontal transmission of hepatitis B virus surface antigen mutant G145R

Objectives: To provide intra-familial evidence on the horizontal transmissi on of hepatitis B virus surface antigen (HBsAg) mutant G145R. Methods: Serum samples from family members of 10 vaccinated infants who car ried this G145R mutant were collected. The presence of the mutant was analy sed by polymerase chain reaction (PCR) and sequencing. Results: The G145R mutant was identified in family members of three of the 10 infants. In family 1, the mutant found initially in child I was identifi ed in another child and the father. In families 2 and 3, the G145R mutant d etected previously in child 1 was detected in the father. Additional mutati ons in HBsAg were identified in at least two members in family 1 and 2, sug gesting horizontal transmission of the mutant among them, The G145R mutant was found in samples with high levels of neutralizing antibody against HBV (anti-HBs). In addition, liver damage was seen in one G145R carrier infant. Conclusions: The G145R mutant could be transmitted horizontally among famil y members, and this could occur in the presence of high levels of anti-HBs. Improvement of detection system for the G145R and other IIBsAg mutant will be needed for their effective control. (C) 2000 The British Infection Soci ety.