孕期应用乙型肝炎免疫球蛋白对预防乙型肝炎病毒垂直传播的预防作用

目的探讨孕期应用乙肝免疫球蛋白(HBIG)对乙肝表面抗原及e抗原双阳性孕妇乙肝母婴垂直传播的预防作用。方法外周血HBsAg阳性孕妇291例,HBsAg、HBeAg双阳性83例,分为HBIG(A组,59例)及非HBIG(B组,24例)组;所有新生儿在出生24 h内,1、6个月分别注射乙肝疫苗并检验乙肝两对半。结果1.HBeAg阳性孕妇的外周血HBV-DNA阳性率为76.56%,显著高于HBeAg阴性孕妇(8.22%),P<0.01;2.孕晚期应用1,2次或3次HBIG的新生儿各月龄HBsAg阳性率及HRsAb阳转率无显著差异;3.A组新生儿出生当天外周血HBsAg阳性率显著低于B组,P<0.05;B组乙肝疫苗免疫后的6个月龄婴儿外周血HBsAb阳转率仅37.5%,显著低于A组(81.4%),P<0.001。结论孕晚期应用HBIG可有效降低乙肝宫内感染率,提高6个月龄婴儿HBsAb阳转率。     

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目的探讨乙肝病毒表面抗原(HBsAg)阳性孕妇分娩新生儿乙肝病毒标志的临床意义。方法对1999-07—2002-06北京地坛医院儿科996例新生儿生后第3天检测静脉血乙肝病毒标志,追踪观察199例成长到3个月至4岁,将乙肝病毒标志HBsAg和HBeAg进行分析。结果新生儿生后第3天HBsAg和HBeAg阳性率分别为27.2%(271/996)、48.1%(479/996),有495例检测抗-HBc,阳性率高达99.2%(491/495)。在生后3个月至4岁间复测乙肝病毒标志199例,有17例感染乙肝病毒,占8.5%(17/199)。分别比较生后第3天血清HB-sAg、HBeAg滴度,感染乙肝病毒新生儿的HBsAg滴度高于未感染新生儿(P<0.01),而HBeAg滴度水平差异不明显(P>0.05)。将感染、未感染乙肝病毒儿童复查结果与生后第3天血清HBsAg、HBeAg滴度分别进行比较,17例感染乙肝病毒儿童血清HBsAg和HBeAg滴度明显升高(P<0.001,P<0.05),而182例未感染儿童明显减低(P<0.001)。结论HBsAg阳性孕妇分娩新生儿血清HBsAg、HBeAg和抗-HBc阳性不能作为诊断感染乙肝病毒的依据,新生儿血清HBsAg滴度较高并在生后3个月逐渐升高,可以作为儿童感染乙肝病毒的诊断依据。     

National Project on the Prevention of Mother-to-Infant Infection by Hepatitis B Virus in Japan

In Japan, a nationwide prevention program against mother-to-infant infection by hepatitis B virus (HBV) started in 1985. This program consists of double screenings of pregnant women and prophylactic treatment to the infants born to both hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) positive mothers. These infants are treated with two injections of hepatitis B immune globulin (HBIG) and at least three injections of plasma derived hepatitis B vaccine. We sent questionnaires about the numbers of each procedure or examination during nine months of investigation period to each local government in 1986 and 1987. 93.4% pregnant women had the chance to be examined for HBsAg, and the positive rate was 1.4 to 1.5%. The HBeAg positive rate in HBsAg positive was 23 to 26%. The HBsAg positive rate in neonates and in infants before two months were 3% and 2% respectively. Some problems may arise, because 27 to 30% of infants need the fourth vaccination in some restricted areas.     

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目的 探讨乙型肝炎病毒携带产妇所生新生儿血清乙型肝炎病毒标志物(HBV-M)转归.方法 2001年3月至2006年3月在暨南大学附属第一医院进行产前检查的500例HBsAg阳性产妇所生新生儿,根据母亲HBeAg状态分为HBeAg阳性组144例,HBeAg阴性组356例.两组新生儿在出生12 h内均注射乙型肝炎免疫球蛋白100 IU,并按常规0、1、6方案分别在出生时、1月龄和6月龄注射基因重组乙型肝炎疫苗5μg,注射主被动免疫前分别抽取外周静脉血检测HBV-M.结果 两组新生儿出生时外周血HBsAg、HBeAg均阳性者分别为24例和9例,追踪至6月龄时HBsAg阳性例数分别为10例和5例,HBsAg阴转率差异无统计学意义.两组新生儿出生时HBsAg阳性、HBeAg阴性者分别为4例和21例,追踪至6月龄时,HBsAg阴转率分别为100%和85.7%.出生时HBsAg阴性、HBeAg阳性者,HBeAg阳性组为29例,占20.1%,显著高于HBeAg阴性组比例(P＜0.01),其6月龄HBsAg阳转率为6.9%,明显低于HBeAg阴性组(P＜0.01).在接受全程主被动免疫的情况下,HBeAg阳性组新生儿6月龄HBsAg和HBsAb阳性率分别为9.7%和67.4%,HBeAg阴性组分别为3.1%和78.1%,两组比较差异有统计学意义(P＜0.05).结论 新生儿出生时外周血HBsAg阳性不能作为判断宫内感染的指标,HBeAg阳性新生儿预后与母亲HBeAg状态密切相关,母亲HBeAg阳性会抑制新生儿对乙型肝炎疫苗的反应.     

预防乙型肝炎病毒母婴传播的随机对照研究

目的探讨乙肝免疫球蛋白（HBIG）预防乙型肝炎病毒（HBV）母婴垂直传播的效果。方法以2001年1月至2005年5月在台州医院产科初次进行妊娠健康检查,HBsAg测定阳性或HBsAg、HBeAg均阳性孕妇作为研究对象,共279例。将单纯HBsAg阳性孕妇与HBsAg、HBeAg双阳性孕妇分别应用随机数表方法随机分组,分别为单阳注射组（n=80）、单阳对照组（n=60）、双阳注射组（n=79）、双阳对照组（n=60）。单阳注射组、双阳注射组于妊娠加周开始肌肉注射HBIG 200U,每4周注射1次,直至临产。两对照组不注射HBIG。4组孕妇所产婴儿,除常规接种乙肝疫苗外,均于出生后16h内和2周肌肉注射HBIG。然后随访并测定婴儿HBsAg。结果单阳注射组、单阳对照组、双阳注射组、双阳对照组所生婴儿HBsAg感染率分别为3％、13％、10％、32％。单阳注射组与单阳对照组之间（x^2=6．07,P〈0．05）,以及双阳注射组与双阳对照组之间婴儿HBsAg感染率（x^2=10．11,P〈0．01）均有统计学意义,注射HBIG组,对单纯HBsAg阳性孕妇及HBsAg、HBeAg双阳性孕妇,出生婴儿HBsAg感染率均显著低于对照组;单阳注射组与双阳注射组之间婴儿HBsAg感染率差异亦有统计学意义,说明HBIG对单纯HBsAg阳性孕妇预防效果优于HBsAg、HBeAg双阳性孕妇。结论HBIG能有效预防母婴传播,降低HBV感染率。因此,妊娠妇女应及时进行健康检查,发现HBV感染阳性,及时采取注射HBIG等有效措施,以促进优生优育。     

Lack of perinatal transmission of hepatitis B virus infection in Senegal, West Africa

Between 1977 and 1980, 1442 pregnant women in Thies, Senegal, were tested for serologic markers of hepatitis B virus (HBV) infection. Of these, 9.8% were HBsAg(+), 59.9% were anti-HBs(+), and 15.6% had anti-HBc alone. Of 116 HBsAg(+) pregnant women, only 19.8% were HBeAg(+), a much lower proportion of infectious carriers than seen in Asian populations. Cord blood from 1353 babies was HBsAg(-), implying that the babies were not infected prior to birth. Four hundred sixty-two babies, including 88 born to HBsAg(+) mothers, were observed for 2 weeks to 38 months after birth. In contrast to observations in Asia, none of the babies became HBsAg(+) before 5 months of age, and only three of the 16 born to HBeAg(+) mothers became HBsAg(+) within the first year of life; all three developed chronic infections (i.e., HBsAg(+) for greater than or equal to 6 months. In the second year of life, six of 34 babies born to HBsAg(+), HBeAg(-)/anti-HBe(-) mothers became infected with HBV, and four of the six developed chronic infections. During the first 3 years of life, infections occurred at a higher rate in infants born to HBsAg(+) (17%) than to HBsAg(-) (4%) women. The latter group of infants included 4.0% of those born to anti-HBs(+) mothers, 4.6% born to anti-HBcAg(+), and 3.2% born to uninfected women. These observations indicate that HBV infections in Senegal usually do not occur perinatally, but do occur at high incidence later in infancy and childhood. Such infections can be prevented by the use of hepatitis B vaccine alone; administration of hepatitis B immune globulin should not be needed.     

乙型肝炎病毒宫内感染对新生儿外周血细胞因子干扰素γ和白介素4的影响

目的 探讨乙型肝炎病毒(HBV)侵犯新生儿外周血单个核细胞(PBMC)后,对新生儿免疫功能的影响,了解其免疫失败发生的机理.方法 聚合酶链反应法(PCR)检测67对乙型肝炎表面抗原(HBsAg)、乙型肝炎e抗原(HBeAg)阳性孕妇及其新生儿血清和PBMC的HBV DNA.根据新生儿PBMC中HBV DNA分成阴性和阳性组,将新生儿的PBMC分别在植物血凝素(PHA)和纯化HBsAg刺激下进行体外细胞培养,检测培养上清液中干扰素-γ(IFN-γ)、白介素-4(IL-=4)的分泌含量.结果 (1)35例母亲PBMC HBV DNA阳性者其新生儿15例为阳性,母亲与患儿PBMC HBV DNA阳性,差异有显著统计学意义(P＜0.01).(2)新生儿PBMC内HBV DNA阳性组与阴性组比较,纯化HBsAg刺激时,阳性组IFN-γ的分泌量较阴性组低(P＜0.01),IL-4含量显示PBMC HBV DNA阳性组高于阴性组(P＜0.05),PHA刺激时,两组IFN-γ、IL-4含量差异无统计学意义(P＞0.05).结论 PBMC内的HBV DNA可能是HBV母婴垂直传播的一条重要途径;宫内新生儿PBMC感染HBV,IFN-γ特异性反应低下,而IL-4特异性反应增强,细胞调节失衡,可能是新生儿免疫失败和易于免疫耐受的一个重要原因.     

Significance of measurement of pre-S2 antigen for the prevention of vertical transmission of hepatitis B virus in infants born to HBsAg carrier mothers

Terazawa S, Kondo N, Orii T. Significance of measurement of pre-S2 antigen for the prevention of vertical transmission of hepatitis B virus in infants born to HBsAg carrier mothers. Acta Pædiatr 1994;83:30–4. Stockholm. ISSN 0803–5253
The significance of pre-S2 antigen (pre-S2 Ag) as a marker of hepatitis B virus (HBV) infection, especially in infants born to HBsAg carrier mothers who are HBeAg-negative or HBeAg-positive, was evaluated. Pre-S2 Ag was measured by enzyme immunoassay. HBsAg carrier mothers who were HBeAg-negative and HBeAb-positive were divided into two groups: group A, mothers whose infants were not infected with HBV ( n = 10) and group B, mothers whose infants were infected with HBV ( n = 13). Absorption rates of pre-S2 Ag in group A and B were 0.09 k 0.04 and 1.36 ± 0.95, respectively. The values for pre-S2 Ag in group B were significantly higher than those in group A. Values for pre-S2 Ag among HBsAg carrier mothers who were HBeAg-positive and HBeAb-negative were also measured by reversc passive hemagglutination. In the same way, HBsAg carrier mothers who were HBeAg-positive and HBeAb-negativc were divided into two groups: group C, mothers whose infants did not become HBsAg carriers ( n = 15) and group D, mothers whose infants became HBsAg carriers (n = 11). The titers of pre-S2 Ag (reverse passive hemagglutination) in group C and D were 2^{5.75 ± 1.68} and 2^10.45±^1.69, respectively. The values for pre-S2 Ag in group D were significantly higher than those in group C. The values for pre-S2 Ag as markers of infectivity became higher with increasing amounts of HBV-DNA. Therefore, our results show that measurement of pre-S2 Ag in HBsAg carrier mothers who are HBeAg or HBeAb-positive is useful in the detection of high-risk groups of vertical transmission of HBV.     

Evaluation of screening for hepatitis B surface antigen during pregnancy in a population with a high prevalence of hepatitis B surface antigen-positive/hepatitis B e antigen-negative carriers

BACKGROUND: Universal hepatitis B vaccination in infancy was implemented in Israel in 1992. The program consists of active vaccination at birth and at 1 and 6 months of age, without hepatitis B surface antigen (HBsAg) screening during pregnancy. Infants of HBsAg carrier mothers do not receive specific hepatitis B immunoglobulin in addition to vaccine at birth. The recently arrived Jewish immigrants from Ethiopia are the group with the highest rate of HBsAg carriage (approximately 10%) in Israel. AIM: The objective of this study was to evaluate whether the present policy is effective against perinatal HBV transmission from mothers of Ethiopian origin to their infants. METHODS: The study group included 411 Israeli born children, offspring of mothers of Ethiopian origin. All infants were fully vaccinated starting at birth. Sera were collected from the children at the age of 9 to 36 months and from their mothers. Tests for HBsAg, antibodies to HBsAg (anti-HBs) and antibodies to hepatitis B core antigen (anti-HBc) were performed. RESULTS: Eighty-nine percent of the children had detectable anti-HBs, including 82.2% with protective anti-HBs concentrations (> or =10 mIU/ ml). Although 24 mothers (6.2%) were HBsAg carriers, none of the children was HBsAg-positive. Seven of 394 infants (1.7%) tested positive for anti-HBc. This test became negative in 5 of 6 who were followed for 12 months. The percentage of infants with protective anti-HBs concentrations decreased significantly from 91.4% at 9 to 12 months to 70.1% at 31 to 36 months of age. The mother's infection status was not associated with the infant's response to vaccine. Calculation based on the above data suggests that screening for HBsAg in pregnancy in that group is not cost-effective. CONCLUSIONS: Our results suggest that the Israeli vaccination program against HBV infection is effective, even in a high risk population, and additional measures are not cost-effective.     

Effects of Booster HB Vaccine in Preventing Hepatitis B Virus Infection from Mother to Child

Hepatitis B immune serum 200 IU was injected intramuscularly to 127 infants born to hepatitis B e antigen positive mothers immediately after birth and at two months of age, and if necessary at four months. HB adjuvant vaccine 20 μg was injected subcutaneously at three, four, and six months. If antibodies to hepatitis B surface antigen were 2² or less, one to four doses of booster vaccine 20 μg were given. The first booster vaccination was given in 8.7% of cases by the age of one year, in 19.3% by 18 months, in 23.9% by 24 months, and in 36.2% by 30 months; thus 2-to-3-year-old infants were more frequently vaccinated than younger ones. This implies that 80%-90% of infants could be protected from vertical transmission of hepatitis B virus (HBV) up to the age of three years, if a booster vaccine was given to those born to HBeAg positive mothers not later than 24 months. Infants obtained enough antibody to prevent HBV infection by receiving one booster vaccination in 34 cases, by two in nine, by three in five, and by four in two.     

Infection with hepatitis B virus in infancy. A longitudinal study of 8 cases.

Eight infants who developed HBsAg aged between 1 and 5 months were identified in the greater Copenhagen area during the period 1970--76. 7 had acquired the infection from their mothers and one had received a HBsAg-positive blood infusion, 3 infants had a transient infection lasting 2 to 8 months while the remaining cases developed persistent antigenaemia with evidence of minor liver dysfunction during a follow-up of one to 6 years. HBeAg was persistently present in 4 of 5 infants, indicating infectivity in these patients. Prematurity or administration of specific immunoglobulin at delivery apparently did not affect the course of infection.     

Prospective study of mother-to-infant transmission of hepatitis C virus

BACKGROUND: Mother-to-infant transmission of hepatitis C virus (HCV) could become the main route of HCV infection in the future because there are no methods available to prevent vertical infection. The aim of this study was to determine the incidence of mother-to-infant transmission in infants born to mothers who tested positive for anti-HCV antibodies and to elucidate associated risk factors for transmission. METHODS: Screening was conducted for 16,800 pregnant women with an anti-HCV antibodies test, and 154 mothers were positive. From the positive group 141 mothers were enrolled in the study and their 147 infants were followed from birth for serum alanine aminotransferase activity, anti-HCV antibodies and HCV RNA. HIV infection was tested in 73 of 141 mothers, all of whom were negative. RESULTS: Thirty-three infants were dropped from the study because they were followed for <6 months or were not tested adequately. Of the 114 infants finally evaluated 9 (7.8%) had detectable HCV RNA. The transmission rate was not influenced by the mode of delivery [vaginal delivery, 8 of 90 vs. cesarean section, 1 of 24 (P = 0.396)] or by the type of feeding [9 of 98 for breast-fed infants vs. 0 of 16 for formula-fed infants (P = 0.243)]. All infected infants were born to mothers who had HCV viremia at the delivery (P = 0.040) and to those with a high viral load (P = 0.019). CONCLUSIONS: Our prospective study showed that the transmission rate of mother-to-infant HCV infection was 7.8% in anti-HCV antibody-positive mothers. Risk was related to the presence of maternal HCV viremia at delivery and a high viral load in the mothers.     

Hepatitis B virus infection

Hepatitis B virus (HBV) infection is a worldwide health problem and may cause acute, fulminant, chronic hepatitis, liver cirrhosis, or hepatocelullar carcinoma (HCC). Infection with HBV in infancy or early childhood may lead to a high rate of persistent infection (25-90%), while the rates are lower if infection occurs during adulthood (5-10%). In most endemic areas, infection occurs mainly during early childhood and mother-to-infant transmission accounts for approximately 50% of the chronic infection cases. Hepatitis B during pregnancy does not increase maternal mortality or morbidity or the risk of fetal complications. Approximately 90% of the infants of HBsAg carrier mothers with positive hepatitis B e-antigen (HBeAg) will become carriers if no immunoprophylaxis is given. Transplacental HBeAg may induce a specific non-responsiveness of helper T cells and HBcAg. Spontaneous HBeAg seroconversion to anti-HBe may develop with time but liver damage may occur during the process of the immune clearance of HBV and HBeAg. Mother-to-infant transmission of HBV from HBeAg negative but HBsAg positive mothers is the most important cause of acute or fulminant hepatitis B in infancy. Although antiviral agents are available to treat and avoid the complications of chronic hepatitis B, prevention of HBV infection is the best way for control. Screening for maternal HBsAg with/without HBeAg, followed by three to four doses of HBV vaccine in infancy and hepatitis B immunoglobulin (HBIG) within 24h of birth is the most effective way to prevent HBV infection. In areas with a low prevalence of HBV infection or with limited resources, omitting maternal screening but giving three doses of HBV vaccine universally in infancy can also produce good protective efficacy. The first universal HBV immunisation programme in the world was launched in Taiwan 22 years ago. HBV infection rates, chronicity rates, incidence of HCC and incidence of fulminant hepatitis in children have been effectively reduced.     

Hepatitis B in children. II. Study of children born to chronic HBsAg carrier mothers

A survey of 4,452 pregnant women taken to find hepatitis B surface antigen revealed 28 asymptomatic chronic carriers. At birth, 16 of 17 infants studied were negative for HBsAg, whereas anti-HBc was present in all patients at a titer similar to that of the mother. Twelve children were followed for 6 to 18 months. In four of them, HBsAg remained negative and anti-HBc titers progressively decreased and were undetectable when tested after the age of 6 months. In eight infants, HBsAg became positive after an average time of 48 days. Elimination of HBsAg occurred in seven infants; five of them had clinical and biological manifestations of mild hepatitis. Sequential determinations of total complement and C components in three patients of the latter group showed dperession of complement at the time of appearance of clinical manifestations. In the patient who became an HBsAg carrier as well as in three infants who remained HBsAg negative, no decrease in complement titers was observed. These results indicate that vertical transmission from carrier mothers can occur in a low prevalence area and that neonatally infected children are capable of active elimination of HBV.     

Hepatitis B Virus Infection in the Infants Born to HBe Antigen Negative Carrier Mothers: A Preliminary Report

One hundred infants born to hepatitis-Be antigen (HBeAg)-negative carrier mothers were followed with or without the administration of hepatitis-B vaccine (HB vaccine) and/or hepatitis-B hyperimmune globulin (HBIG). Among the infants without treatment, 7.6% of the infants born to the antibody-to HBeAg (anti-HBe)-positive carrier mothers and 14% of those born to the carrier mothers without HBeAg and anti-HBe developed HBs-antigenemia, whereas none of the infants treated became positive for HBsAg. The results indicate the necessity for preventive measures for the babies born to HBsAg-carrier mothers, regardless of their HBeAg state.     

Use of hepatitis B vaccine alone or in combination with hepatitis B immunoglobulin for immunoprophylaxis of perinatal hepatitis B infection.

The efficacy of hepatitis B vaccine alone or in combination with immunoglobulin in neonates born to HBsAG positive mothers was investigated. Twenty-four infants were given three doses (at 0, 1, 2 months) of the vaccine alone, while 27 infants were given hepatitis B immunoglobulin (HBIG) and three doses of the vaccine. Fifty-eight infants born to HBsAg positive mothers who did not agree for vaccination or could not come for follow-up constituted the control group. The overall seroprotection rates (anti-HBS levels > or = 10 IU/l) were almost similar in both the groups at 6 months (81 and 76 per cent, respectively). However, the seroprotection rates in babies born to HBeAg positive mothers were better with combination of HBIG and vaccine (71 v. 57 per cent, respectively). It was also observed that seroprotection rates in babies born to anti-HBe positive mothers were even better (100 and 90 per cent in vaccine alone and combination group, respectively). No chronic carrier was detected in babies born to anti-HBe positive mothers.     

胎盘Hofbauer细胞在乙型肝炎病毒母婴垂直传播中的作用

目的 探讨胎盘Hofbauer细胞与乙型肝炎病毒（HBV）垂直传播的相关性。方法应用光学显微镜和免疫组织化学技术观察垂直传播组（母亲及新生儿HBsAg和HBV-DNA均为阳性）14例、非垂直传播组（母亲HBsAg和HBV-DNA阳性，新生儿为阴性）62例和正常对照组（母亲及新生儿HBsAg和HBV-DNA均为阴性）10例的胎盘结构变化、胎盘HBV感染与Hofbauer细胞的关系。结果1．垂直传播组和非垂直传播组孕妇胎盘组织存在坏死、水肿、绒毛动脉硬化、绒毛间质纤维化和纤维素样沉积，多形核自细胞、淋巴细胞、颗粒细胞浸润。2．垂直传播组胎盘HBsAg阳性率为100．0％；非垂直传播组为58．0％，差异具有显著性（P=0．013）。阳性信号主要出现在滋养细胞、Hofbauer细胞和血管内皮细胞。3．垂直传播组胎盘Hofbauer细胞数目明显增加，结合HBV的阳性Hofbauer细胞明显高于非垂直传播组和对照组（P均〈0．01）。结论HBV可与胎盘Hofbauer细胞结合，可能介导HBV的母婴垂直传播。     

Follow-up of transmission of hepatitis C to babies of human immunodeficiency virus-negative women: the role of breast-feeding in transmission

BACKGROUND: The studies on hepatitis C virus (HCV) vertical transmission, the effect of potential risk factors and the role of breast-feeding have reported conflicting results. PATIENTS AND METHODS: Seventy-three infants of 63 anti-HCV-positive and anti-HIV-negative mothers were studied from 1993 to 1999 in the south of Spain. The mean period of follow-up in children was 29.2 +/- 19 months (range, 8 to 76 months); 6 (8%) children were lost to follow-up. Breast milk was studied for HCV-RNA in 68 samples of 35 mothers. RESULTS: Alanine aminotransferase was high in 19 (26%) and HCV-RNA was positive in 46 (63%) pregnant woman. Breast milk HCV-RNA was negative in nonviremic mothers and positive in 20% of the viremic mothers. The overall rate of vertical HCV transmission was 11.9% (n = 8) (95% confidence interval, 6 to 23%) if HCV-RNA was positive one or more times, but only 1.5% (n = 1) (95% confidence interval, 0.1 to 9%) if HCV-RNA was permanently positive. Seven HCV-infected children did not develop antibodies to HCV, and they had a spontaneous clearance of the virus. A 10-month-old baby was HCV-RNA-positive from birth to the end of the follow-up. The genotype in each of the infants was consistent with that of their mother. The rate of HCV transmission was higher for infants of mothers with higher HCV viremia (P < 0.01) and also for infants whose mothers were HCV-RNA-positive in breast milk (P < 0.05). There were no statistically significant differences between other risk factors. CONCLUSION: The presence of transitory viremia without seroconversion indicates that the vertical transmission of HCV is not important. This could be related to the viral charge and ingestion of milk of HCV-RNA-positive mothers. However, to advise avoidance of maternal breast feeding, it would be necessary to conduct larger studies.     

Factors affecting clearance of hepatitis B e antigen in hepatitis B surface antigen carrier children

To understand the natural history of chronic hepatitis B virus infection in children, we studied factors affecting the clearance of hepatitis B e antigen (HBeAg). One hundred sixty-nine apparently healthy children whose sera were positive for HBeAg and hepatitis B surface antigen (HBsAg) and who were recruited by screening were followed prospectively to delineate the HBeAg clearance rate. Another 59 carrier children visiting the outpatient clinic because of symptoms or abnormal liver function were studied for comparison. The annual HBeAg clearance rate was low (less than 2%) during the first 3 years of life but increased with age. The HBeAg clearance rate in children older than 6 years of age was lower in those whose mothers had HBsAg positivity (14.3%) than in those whose mothers had no detectable HBsAg (35.3%). Children who were brought for medical care had higher HBeAg clearance rates (42.4%) than those who were recruited by screening (14.6%) because immune clearance of hepatitis B virus and hence HBeAg often led to hepatocellular damage manifested by abnormal liver function profiles or by symptoms that had caused the parents to seek medical care for their children. We conclude that age, source of subject recruitment, and maternal HBsAg status are important factors affecting HBeAg clearance rate in HBsAg carriers.     

Hepatitis B virus infection and its transmission in preschool children.

In the present study, 2.5% of 367 preschool children has HBsAg positivity. Of 11 mothers who were HBsAg positive during the third trimester of pregnancy, 4 had babies (36.4%) who developed HBsAg positivity by 2.5-3 months of age (vertical transmission). Two babies born of HBsAg negative mothers, with history of jaundice during first trimester, were HBsAg negative. All the relatives of HBsAg positive cases screened were negative for HBsAg.