EFFICACY OF IMMUNIZATION OF HIGH-RISK INFANTS AGAINST HEPATITIS-B VIRUS EVALUATED BY POLYMERASE CHAIN-REACTION

The polymerase chain reaction (PCR) is a rapid and very sensitive meth od to detect viral genomes. In the present study, the efficacy of immu nization against hepatitis B virus (HBV) of high-risk infants was eval uated by PCR. Twenty-nine infants born to 24 HBeAg-positive carrier mo thers were given hepatitis B immune globulin (HBIG) at birth and there after received repeated inoculations of plasma-derived vaccine or HBIG , or both, within 1 year. Serum samples at 1 year following immunizati on were stored at -40 degrees C for later analysis using PCR to detect HBV-DNA. When HBV genomes were detected in infants, the DNA sequences in the S gene of HBV were determined. Of 29 infants, 2 were positive for HBV-DNA at the 1 year following immunization; one had the HBV cont aining only the wildtype sequence in the S gene and became negative fo r HBV-DNA during the follow-up period. In contrast, another had the HB V, which contained nucleotide substitutions that altered the expressio n of the common group-specific determinant ''a'' of the S gene and res ulted in clinical hepatitis with viral persistence. PCR analysis sugge sts that immunization against HBV prevents effectively high-risk infan ts from mother-to-child transmission. Even then, however, it is possib le that amino acid substitutions in the ''a'' determinant of the S gen e are associated with failure of conventional immunization against HBV . (C) 1997 Wiley-Liss, Inc.