A prospective study on the mother-to-infant transmission of hepatitis C virus and the prognosis of the infected infants.

母婴传播丙型肝炎病毒（HCV）被怀疑是该病毒自然感染的最重要途径之一，但其频率和影响这种感染的因素尚不清楚。由于成人感染丙型肝炎病毒后也会出现携带者状态，而乙型肝炎病毒很少出现，因此对丙型肝炎病毒携带者家庭的回顾性研究无法阐明上述问题。在这项研究中，我们对通过筛查发现的HCV携带者母亲或孕妇所生的婴儿进行了前瞻性随访研究。对日本6个不同地区的孕妇进行了HCV血清抗体（第二代，抗HCV）筛查，如果阳性，则使用聚合酶链反应检测血清HCV RNA。0.45 ~ 1.5%（平均1%）的孕妇抗-HCV阳性，71% ~ 76%的抗-HCV阳性妇女血清HCV RNA阳性。抗丙型肝炎病毒阳性孕妇所生的婴儿在出生后每隔一到三个月随访一年多，检查他们的血清抗丙型肝炎病毒、丙型肝炎病毒RNA和转氨酶水平。到目前为止，325名婴儿在出生后6个多月的随访中，其中17名婴儿发展为慢性HCV携带者状态，所有这些婴儿都是HCV-RNA阳性母亲的产物，HCV RNA阴性母亲所生的婴儿均未出现HCV感染的迹象。在HCV RNA阳性母亲所生的婴儿中，HCV携带者的平均百分比为5.4%。另有7名婴儿在6个月前表现出短暂性丙型肝炎病毒感染。密切评价母婴感染的各种因素发现，1)HCV感染婴儿的母亲血清HCV RNA水平较高，但2)HCV基因型之间感染率无差异，3)血清中病毒颗粒密度梯度状态之间无差异，4)母乳喂养和奶瓶喂养婴儿之间无差异。

Mother-to-infant transmission of hepatitis C virus (HCV) is suspected as one of the most important routes of natural infection of this virus, but its frequency nor factors affecting this infection are not known. Since the carrier status develops even when adults are infected by HCV,which is rare by hepatitis B virus, the retrospective study of the families of HCV carriers cannot elucidate the above mentioned problems. In this research we conducted a prospective follow-up study of the infants born to HCV carrier mothers found by screening or pregnant women.Pregnant women in six different districts of Japan were screened for serum antibody for HCV (second generation, anti-HCV) and if it was positive the serum HCV RNA was examined using polymerase chain reaction. 0.45 to 1.5% (mean 1%) of the pregnant women were positive for anti-HCV,and 71 to 76% of anti-HCV positive women were also positive for serum HCV RNA.Infants born to anti-HCV positive pregnant women were followed after birth with intervals of one to three months for more than one year after birth, examining their sera for anti-HCV,HCV RNA,as well as transaminase levels. Until now 325 infants had been followed for more than six months after birth, and seventeen of them developed chronic HCV carrier status, all of whom were the products of HCV-RNA positive mothers, and none of the infants born to HCV RNA negative mothers showed the sign of HCV infection. The mean percentage of the development of HCV carrier status was 5.4% among the infants born to HCV RNA positive mothers. There were seven other infants who showed transient infection by HCV before six months of age.Close evaluation of various factors regarding mother-to-infant infection disclosed that 1) the mothers of HCV infected infants showed higher serum HCV RNA level, but 2) no difference of infection rate was found between HCV genotypes, 3) between the density gradient status of virus particles in sera, nor 4) between breast-fed and bottle-fed infants.