Secular trend of the viral genotype distribution in children with chronic hepatitis B virus infection after universal infant immunization.

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Hepatology. 2011 Feb;53(2):429-36. doi: 10.1002/hep.24061. Epub 2011 Jan 10.

Secular trend of the viral genotype distribution in children with chronic

hepatitis B virus infection after universal infant immunization.

Wen WH, Chen HL, Ni YH, Hsu HY, Kao JH, Hu FC, Chang MH.

Department of Pediatrics, College of Medicine and Hospital, National Taiwan

University, Taipei, Taiwan; Department of Pediatrics, Cardinal Tien Hospital,

Taipei, Taiwan; School of Medicine, Fu-Jen Catholic University, Taipei, Taiwan.

Abstract

Genotypes B and C are the major hepatitis B virus (HBV) genotypes in Taiwan, and

genotype C is associated with more severe liver disease than genotype B. Whether

the implementation of the hepatitis B immunization program has affected the

secular trend of the HBV genotype distribution remains unknown. We thus

investigated the HBV genotypes in hepatitis B surface antigen (HBsAg)-carrier

children born before the implementation of the universal infant immunization

program and in those born afterward. One hundred seven children who were

infected with HBV despite appropriate immunization were enrolled as immunized

cases with HBV breakthrough infection. Each case was matched with two

unimmunized HBsAg carriers according to the age at enrollment. HBV genotypes

were determined with molecular methods. Compared with unimmunized HBsAg

carriers, more immunized children had HBsAg-positive mothers (65.9% versus 100%,

P < 0.001) and were infected with genotype C (16.4% versus 42.1%, P < 0.001).

Among the children born to HBsAg-positive mothers, the mothers' and children's

HBV genotypes were highly concordant in both unimmunized [ê = 0.97, 95%

confidence interval (CI) = 0.90-1.00] and immunized children (ê = 0.97, 95% CI =

0.92-1.00). After adjustments for gender, maternal age, and delivery mode,

immunized HBsAg-carrier children born to HBsAg-positive mothers had a higher

likelihood of genotype C infection than unimmunized children (odds ratio = 3.03,

95% CI = 1.62-5.65, P = 0.001). However, the increased genotype C to genotype B

ratio was not seen in the HBsAg-carrier mother pool in the postimmunization era.

Conclusion: In the postimmunization era, most HBV breakthrough infections are

due to maternal transmission, and immunized children born to genotype C mothers

may have a higher rate of breakthrough infection than those born to genotype B

mothers. (HEPATOLOGY 2011;53:429-436.).

American Association for the Study of Liver Diseases.

PMID: 21274864 [PubMed - in process]