Demonstration of mother-to-infant transmission of hepatitis B virus by means of polymerase chain reaction.

To investigate the failure of vaccines to prevent mother-to-infant transmission of hepatitis B virus (HBV), serum, cord blood, and colostrum samples from eleven mothers, known to be carriers of hepatitis B surface antigen, and their infants were examined by means of a highly sensitive polymerase chain reaction (PCR) method. HBV-specific DNA was detected in ten maternal serum samples, eight samples of colostral whey, eight samples of colostral cells, and one cord blood sample. Four infants of mothers with HBV-DNA-positive colostrum showed low responsiveness to hepatitis B vaccine. The infant whose cord blood was positive for HBV DNA showed low responsiveness to hepatitis B vaccine and subsequently became an HBV carrier. These results suggest the need for further study to evaluate whether breastfeeding is advisable for HBV carriers.