Department of Pediatrics, College of Medicine and Hospital, National Taiwan University, Taipei, Taiwan.
Hepatology. 2011 Feb;53(2):429-36. doi: 10.1002/hep.24061. Epub 2011 Jan 10.
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 [κ = 0.97, 95% confidence interval (CI) = 0.90-1.00] and immunized children (κ = 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.
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.
乙型肝炎病毒（HBV）基因型 B 和 C 是台湾的主要基因型，与基因型 B 相比，基因型 C 与更严重的肝病相关。实施乙型肝炎免疫接种计划是否影响 HBV 基因型分布的长期趋势尚不清楚。因此，我们调查了实施普遍婴儿免疫接种计划之前和之后出生的乙型肝炎表面抗原（HBsAg）携带者儿童中的 HBV 基因型。我们纳入了 107 名尽管进行了适当免疫但仍发生乙型肝炎突破感染的 HBV 感染者作为免疫突破感染病例。每个病例均根据入组时的年龄与两名未免疫的 HBsAg 携带者相匹配。采用分子方法确定 HBV 基因型。与未免疫的 HBsAg 携带者相比，更多的免疫儿童具有 HBsAg 阳性母亲（65.9%对 100%，P<0.001），并且感染基因型 C（16.4%对 42.1%，P<0.001）。在 HBsAg 阳性母亲所生的儿童中，无论是在未免疫者（κ=0.97，95%置信区间[CI]：0.90-1.00）还是免疫者中（κ=0.97，95%CI：0.92-1.00），母亲和儿童的 HBV 基因型都高度一致。在调整了性别、母亲年龄和分娩方式后，与未免疫者相比，来自 HBsAg 阳性母亲的免疫 HBsAg 携带者儿童更有可能感染基因型 C（比值比[OR]=3.03，95%CI：1.62-5.65，P=0.001）。然而，在免疫后时代，HBsAg 携带者母亲群体中并未出现基因型 C 与基因型 B 比值的增加。
在免疫后时代，大多数乙型肝炎突破感染是由母婴传播引起的，来自基因型 C 母亲的免疫儿童与来自基因型 B 母亲的儿童相比，突破感染的发生率可能更高。
