The role of transplacental hepatitis B core antibody in the mother-to-infant transmission of hepatitis B virus

Influence of different delivery modes and HBV DNA titers on mother-to-child transmission of hepatitis B

BACKGROUND

The influence of different delivery modes on the mother-to-child transmission (MTCT) rate of pregnant women with high hepatitis B viremia was investigated.

METHODS

A retrospective analysis was performed on data for 855 hepatitis- B -virus (HBV) carrier mothers who received regular prenatal care and delivered at the First Affiliated Hospital of Jinan University from January 2011 to October 2015. The neonates were classified into three groups according to the delivery mode: eutocia (438 cases), Non-parturient cesarean delivery (371 cases), and parturient cesarean delivery (46 cases). The neonatal HBV surface antigen (HBsAg) positive rates of the three delivery groups were comparatively analyzed to determine the influence of the delivery mode on HBV MTCT. Of the 855 HBV-carrier mothers, 480 mothers and respective newborns were tested for HBV-DNA and classified into four groups: HBV DNA≥10⁷ copies/mL (96 cases), 10⁵≤HBV DNA<10⁷ copies/mL (37 cases), 10³≤HBV DNA<10⁵ copies/mL (85 cases), and HBV DNA<10³ copies/mL (262 cases). The effect of the HBV DNA titers of these pregnant women on HBV MTCT was analyzed.

RESULTS

Statistically significant (P<0.05) differences were found among the HBsAg positive rates of neonates of HBV-carrier pregnant women delivered by the three methods from HBV-carrier pregnant women with HBV DNA≥107 copies/mL. No statistically significant (P>0.05) differences among the HBsAg positive rates were found for neonates delivered by the three methods from HBV-carrier pregnant women with HBV DNA<10⁷ copies/mL.

CONCLUSIONS

The delivery mode may influence the risk of HBV maternal-to-infant vertical transmission for HBV-carrier pregnant women with HBV DNA≥10⁷ copies/mL. That is, elective cesarean section may reduce the HBV maternal-to-infant vertical transmission.

Prevention of Hepatitis B Virus Infection and Liver Cancer

Hepatocellular carcinoma (HCC) is one of the five leading causes of cancer death in human. Hepatitis B virus (HBV) is the most common etiologic agent of HCC in the world. Prevention is the best way to control cancer. There are three levels of liver cancer prevention, i.e., primary prevention by HBV vaccination targeting the general population starting from birth dose, secondary prevention by antiviral agent for high-risk subjects with chronic HBV infection, and tertiary prevention by antiviral agent to prevent recurrence for patients who have been successfully treated for liver cancer. Primary prevention by hepatitis B vaccination is most cost effective, the cancer preventive efficacy support it as the first successful example of cancer preventive vaccine in human. Addition of hepatitis B immunoglobulin immediately after birth and antiviral agent during the third trimester of pregnancy to block mother-to-infant transmission of HBV are existing or possible emerging strategies to enhance the prevention efficacy of HBV infection and its related liver cancer. Secondary prevention with current antiviral agents may reduce the risk or delay the onset of HCC development, but could not eradicate HBV infection and HCC. Better antiviral therapeutic agents are needed for better secondary prevention.

[Hepatitis B and pregnancy. Part 2. Nine practical issues about delivery and neonatal care]

In France, the hepatitis B maternal-fetal transmission prevention strategy is based on serovaccination at birth. Serum therapy is to inject 30IU/kg of anti-HBs specific immunoglobulins of human origin in the first hours of life, which in practice corresponds to 1ml or 100IU. Vaccination should also be performed during the first hours of life, and a new injection should be performed at 1month and 6months. In infants less than 32weeks and/or less than 2kg, lower vaccine response leads to prescribe an additional injection at 2months. This serovaccination reduces the risk of mother to child transmission from 57 to 4 %. The failure risk factors of serovaccination are high maternal viral load (greater than or equal to 7 log) and/or the presence of HBeAg. The delivery route does not change the risk of maternal-fetal transmission of hepatitis B when serovaccination at birth was well conducted. Likewise, breastfeeding does not change the risk of maternal-fetal transmission of hepatitis B after serovaccination. It is recommended by WHO. During labor, the pH in utero should be done only when strictly necessary, the published data do not allow to conclude on the risk of transmission.

Prevention of neonatal hepatitis B virus transmission

Hepatitis B virus (HBV) vertical transmission remains a worldwide issue but is fairly uncommon in the western world due to routine screening and vaccination. Universal screening of pregnant women during the second trimester facilitates interruption of mother-to-child transmission (MTCT) by identifying HBV-infected mothers for whom intervention may reduce MTCT risk. HBV DNA level is the single most important predictor of MTCT. Other risk factors include HBeAg, HBe Ab, anti-HB core IgG, and HIV status. Current recommendations for infants born to HBsAg-positive mothers include administration of HBIG within 12 hours of birth and first dose of HBV vaccine within 24 hours of birth. Antiviral therapy is recommended in the third trimester of pregnancy in a subset of patients based on HBeAg and HBV DNA status for prophylaxis of MTCT, although discontinuation of antivirals after delivery is associated with significant increased risk of flares. This article outlines the data for prevention of vertical transmission of HBV.

Prevention of hepatitis B virus infection and liver cancer

Hepatocellular carcinoma (HCC) is one of the five leading causes of cancer death in human. Hepatitis B virus (HBV) is the most common etiologic agent of HCC in the world, particularly in areas prevalent for HBV infection such as Asia, Africa, southern part of Eastern and Central Europe, and the Middle East. Risk factors of HBV-related HCC include (1) viral factors-persistent high viral replication, HBV genotype C or D, pre-S2 or core promoter mutants; (2) host factors-older age (>40 years old) at HBeAg seroconversion, male gender; (3) mother-to-infant transmission; and (4) other carcinogenic factors-smoking, habitual use of alcohol, etc. Prevention is the best way to control cancer. There are three levels of liver cancer prevention, i.e., primary prevention by HBV vaccination targeting the general population, secondary prevention by antiviral agent for high-risk subjects with chronic HBV infection, and tertiary prevention by antiviral agent to prevent recurrence for patients who have been successfully treated for liver cancer. Primary prevention by hepatitis B vaccination is most cost effective. Its cancer preventive efficacy supports it as the first successful example of cancer preventive vaccine in human. This experience can be extended to the development of other cancer preventive vaccine. Careful basic and clinical research is needed to develop ideal vaccines to induce adequate protection. Understanding the main transmission route and age at primary infection may help to set the optimal target age to start a new cancer preventive vaccination program. Besides timely HBV vaccination, the earlier administration of hepatitis B immunoglobulin immediately after birth, and even antiviral agent during the third trimester of pregnancy to block mother-to-infant transmission of HBV are possible strategies to enhance the prevention efficacy of HBV infection and its related liver cancer.

Chronic hepatitis B virus infection and pregnancy

Planning of pregnancy and management of chronic hepatitis B virus during pregnancy includes recognition of maternal virological status, assessment of liver disease severity and minimization of risk for mother to infant transmission of infection. Decisions regarding the use of antivirals during pregnancy need to be individualized. Monitoring for infection and immunization in newborns is also important. For mothers on antiviral therapy, breastfeeding is not recommended.

Active-passive Immunization Effectiveness Against Hepatitis B Virus in Children Born to HBsAg Positive Mothers in Amol, North of Iran

OBJECTIVES

HBV infection is a contagious disease that may transmit vertically from mothers to their neonates or horizontally by blood products and body secretions. Over 50% of Iranian carriers have contracted the infection perinatally, making this the most likely route of transmission of HBV in Iran. This study assesses the serologic markers of HBV in children born to HBsAg positive mothers who received HBIG and 3 doses of HBV vaccine.

METHODS

To evaluate the effectiveness of vaccination against HBV, a study was conducted on 95 Children, born to hepatitis B surface antigen (HBsAg)-positive mothers, who had received Hepatitis B Immune Globulin and HBV vaccines during 2004-2008. All children were tested for the presence of HBsAg, anti-HBs and anti-HB core antigen (anti-HBc).

RESULTS

Among an estimated 30000 pregnant women during the five year study, about 130 (0.42%) were HBV carriers. Ninety-five children from these mothers were enrolled in this study. Only one child (1.1%) was HBsAg positive, while 88.4% of children were Anti-HBs Positive. Eleven children (11.6%) were exposed to HBV as shown by the presence of anti-HBc. A significant difference was observed between the children's age and Anti-HBs (p=0.0001).

CONCLUSION

Passive-active immunoprophylaxis of high risk babies was highly efficacious in preventing perinatal transmission of the HBV carrier state. Also, evaluation of serologic markers in HBV infected people is important for designing the strategies for disease control.

An algorithm for risk assessment and intervention of mother to child transmission of hepatitis B virus

BACKGROUND & AIMS

Despite immunoprophylaxis, mother to child transmission (MTCT) of hepatitis B virus (HBV) still occurs in infants born to hepatitis B surface antigen (HBsAg)-positive mothers. We analyzed methods of risk assessment and interventions for MTCT.

METHODS

We reviewed 63 articles and abstracts published from 1975-2011 that were relevant to MTCT; articles were identified using the PubMed bibliographic database.

RESULTS

Administration of HB immunoglobulin and HB vaccine to infants at birth (within 12 hours), followed by 2 additional doses of vaccines within 6-12 months, prevented approximately 95% of HBV transmission from HBsAg-positive mothers to their infants. However, HBV was still transmitted from 8%-30% of mothers with high levels of viremia. It is important to assess the risk for MTCT and identify mothers who are the best candidates for intervention. The most important risk factor is maternal level of HBV DNA >200,000 IU (10(6) copies)/mL; other factors include a positive test result for the HB e antigen, pregnancy complications such as threatened preterm labor or prolonged labor, and failure of immunoprophylaxis in prior children. Antiviral therapy during late stages of pregnancy is the most effective method to reduce transmission from mothers with high levels of viremia, but elective cesarean section might also be effective. Antepartum administration of HB immunoglobulin, giving infants a double dose of HB vaccine, or avoiding breastfeeding had no impact on MTCT.

CONCLUSIONS

HBsAg-positive mothers should be assessed for risk of MTCT, and infants should receive immunoprophylaxis. Pregnant women with levels of HBV DNA >200,000 IU/mL should be considered for strategies to reduce the risk for MTCT. We propose an algorithm for risk assessment and patient management that is based on a review of the literature and the opinion of a panel of physicians with expertise in preventing MTCT.

HEPATITIS B AND PREGNANCY, THE SCIENTIFIC BASIS FOR PERINATAL PREVENTION

Hepatitis B and its complications are one of the major global health problems. Around 2 billion individuals are infected by hepatitis B virus (HBV) worldwide, more than 350 million are chronically infected, and approximately 15 to 40 percents of them will develop serious complications such as liver cirrhosis, hepatic failure, or hepatocellular carcinoma (HCC). The worldwide prevalence of chronic HBV infection ranges from 0.1 to 20 percent and varies widely in different geographic areas. According to the prevalence rate, WHO has classified countries into 3 levels: high areas (>8%) such as Africa, Asia, Western Pacific and Middle East; intermediate areas (2–8%) such as South America and Eastern Europe, and low areas (<2%) such as Western Europe, North America, and Australia.

[Hepatitis B vaccination: a major player in the control of primary liver cancer]

In worst cases, chronic hepatitis B ultimately leads to primary liver cancer. Populations the more at risk to develop hepatocellular carcinoma (HCC), i.e. patients infected perinatally, reside essentially in Asia. A quarter of century after its introduction in medical practice, data coming from Eastern Asia demonstrate a strong impact of the vaccine on HCC incidence. Strikingly, universal immunization of Taiwanese newborns reduced fourfold pediatric HCC incidence. However, residual cases still appear though among children infected at birth by HBe antigen-carrying mothers. Epidemiologic models indicate that the continuation of universal vaccination policy will reduce chronic hepatitis B endemicity 50-fold in three generations. Recently, mutant forms of HBV potentially escaping to vaccine appeared as a potential consequence of large-scale vaccination. Finally, lack of early immunization of newborns in developing countries still represents a major limitation to the progresses against liver cancer.

Hepatitis B virus translocates across a trophoblastic barrier

Mother-infant transmission of hepatitis B virus (HBV) accounts for up to 30% of worldwide chronic infections. The mechanism and high-risk period of HBV transmission from mother to infant are unknown. Although largely prevented by neonatal vaccination, significant transmission continues to occur in high-risk populations. It is unclear whether HBV can traverse an intact epithelial barrier to infect a new host. Transplacental transmission of a number of viruses relies on transcytotic pathways across placental cells. We wished to determine whether infectious HBV can traverse a polarized trophoblast monolayer. We used a human placenta-derived cell line, BeWo, cultured on membranes as polarized monolayers, to model the maternal-fetal barrier. We assessed the effects of placental maturity and maternal immunoglobulin on viral transport. Intracellular viral trafficking pathways were investigated by confocal microscopy. Free HBV (and infectious duck hepatitis B virus) transcytosed across trophoblastic cells at a rate of 5% in 30 min. Viral transport occurred in microtubule-dependent endosomal vesicles. Additionally, confocal microscopy showed that the internalized virus traverses a monensin-sensitive endosomal compartment. Differentiation of the cytotrophoblasts to syncytiotrophoblasts resulted in a 25% reduction in viral transcytosis, suggesting that placental maturity may protect the fetus. Virus translocation was also reduced in the presence of HBV immunoglobulin. We show for the first time that transcytosis of infectious hepadnavirus can occur across a trophoblastic barrier early in gestation, with the risk of transmission being reduced by placental maturity and specific maternal antibody. This study suggests a mechanism by which mother-infant transmission may occur.

Immunopathogenesis of hepatitis B virus infection

Hepatitis B virus (HBV) infection is a non-cytopathic hepatotropic virus that can lead to severe liver disease including acute hepatitis, cirrhosis and hepatocellular carcinoma. Successful clearance of the virus as well as the establishment of liver disease is largely driven by a complex interaction between the virus and the host immune response. In this review, the immunological events, including both the innate and adaptive immune response are discussed in the setting of both acute and chronic HBV infection and liver disease.

Transformation of hepatitis B serologic markers in babies born to hepatitis B surface antigen positive mothers

AIM: To better understand the clinical significance of hepatitis B serologic markers in babies born to hepatitis B surface antigen (HBsAg) positive mothers, the incidence of maternal serologic markers of hepatitis B via placenta and its transformation in these babies were investigated.

METHODS: Mothers with positive HBsAg were selected in the third trimester of pregnancy. Their babies received immunoprophylaxis with hepatitis B immunoglobulin and hepatitis B vaccine after birth, and were consecutively followed up for hepatitis B serologic markers and HBV DNA at birth, mo 1, 4, 7, 12, and 24.

RESULTS: Forty-two babies entered the study, including 16 born to hepatitis B e antigen (HBeAg)-positive HBsAg carrier mothers and 26 to HBeAg-negative HBsAg carrier mothers. Apart from four babies born to HBeAg-positive carrier mothers and demonstrated persistent positive HBeAg eventually became HBV carriers, all other babies developed anti-HBs before 12 mo of age. Among the other 12 babies born to HBeAg-positive carrier mothers, HBeAg was detected in 7 at birth, in 4 at mo 1, and in none of them thereafter. No antibody response to the transplacental HBeAg was detected. Among the babies born to HBeAg-negative carrier mothers, anti-HBe was detected 100% at birth and mo 1, in 88.5% at mo 4, in 46.2% at mo 7, in 4.2% at mo 12 and none in mo 24. Among all the immunoprophylaxis-protected babies born to either HBeAg-positive or HBeAg-negative carrier mothers, anti-HBc was detected in 100% at birth, mo 1 and mo 4, in 78.9% at mo 7, in 36.1% at mo 12 and in none at mo 24.

CONCLUSION: HBeAg can pass through human placenta from mother to fetus and become undetectable before 4 mo of age, but no antibodies response to the transplacental HBeAg can be detected till mo 24 in the immunoprophylaxis-protected babies. The sole existence of anti-HBe before 1 year of age or anti-HBc before 2 years of age in babies born to HBsAg carrier mothers may simply represent the transplacental maternal antibodies, instead of indicators of HBV infection status.

Decreasing incidence of hepatocellular carcinoma among children following universal hepatitis B immunization

Hepatocellular carcinoma (HCC) is one of the 10 most common malignant tumors worldwide. Chronic infection with hepatitis B or C virus is closely related to hepatocarcinogenesis. The outcome of current therapies for HCC is not satisfactory. Prevention is the best way to control HCC. Among the various strategies of HCC prevention, immunization against hepatitis B virus infection is the most effective. Universal hepatitis B immunization has proved to be effective in reducing the incidence of HCC to 1/4-1/3 of that in children born before the hepatitis B vaccination era in Taiwan. The problems we face in achieving global control of hepatitis-related HCC include: (1) no effective vaccine for the prevention of hepatitis C and its related HCC; (2) no immunization program for hepatitis B in areas with inadequate resources; (3) poor compliance to the immunization program as a result of ignorance, anxiety, or poverty; and (4) vaccine failure. Integration of the hepatitis B vaccination program into the expanded program of immunization for all infants throughout the world will be most urgent and important for HCC control. The reduction of the incidence of HCC will be seen in adults 30-40 years of age after the launch of the universal hepatitis B vaccination program. This concept of cancer vaccine can be applied to other infectious agents and their related cancers.

[Mother-child transmission of hepatitis B virus. State of the problem and prevention]

Hepatitis B virus (HBV) infection is a worldwide problem of public health. Mother/child transmission of the virus represents a major factor in maintaining the infection, which is often transmitted during delivery, the risk of transmission of the HBV depending on the degree of maternal infectiosity, the genomic type of the virus, and the rate of maternal antibodies. Evolution towards chronicity of the infected newborn is frequent. The available means to prevent the mother/child transmission of the virus are efficient. Once HBV maternal infection is diagnosed during pregnancy, joint administration of vaccine and specific immunoglobulins to the baby in the early neonatal period efficiently prevent the mother/child transmission of the virus.

Prospects for hepatitis B virus eradication and control of hepatocellular carcinoma

Hepatitis B virus infection is the most common cause of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma worldwide. In areas hyperendemic for HBV infection, the related complications occur mostly during adulthood. However, nearly half of all primary infection in chronic carriers occurs in the perinatal period through maternal transmission, the other half arising from horizontal transmission mainly through intrafamilial spread or injection using unsterilized needles. A universal vaccination programme is better than immunization for at-risk groups. Hepatitis B vaccination should be integrated into the Expanded Programme on Immunization in children. Universal immunization against hepatitis B virus has proved to be effective in reducing the hepatitis B carrier rate to one-tenth of the prevalence before the vaccination programme in highly endemic areas, and the incidence of hepatocellular carcinoma in children has also been shown to be significantly reduced. Continued efforts to implement universal vaccination programmes worldwide will very likely reduce the incidence of hepatitis B virus-related diseases, particularly liver cirrhosis and hepatocellular carcinoma.

Hepatitis B surface antigenemia at birth: a long-term follow-up study

OBJECTIVE

To investigate the prevalence and outcome of hepatitis B surface antigenemia in newborns of hepatitis B e antigen (HBeAg)-positive hepatitis B surface antigen (HBsAg) carrier mothers under the current immunoprophylaxis program.

STUDY DESIGN

From 1984 to 1993, 665 high-risk newborns born to HBeAg-positive HBsAg carrier mothers were prospectively recruited. The newborns were tested for HBsAg soon after birth, before hepatitis B immune globulin administration. All newborns received hepatitis B immune globulin within 24 hours after birth plus subsequent hepatitis B vaccination. Those who were seropositive for HBsAg at birth were regularly followed up for their hepatitis B virus (HBV) markers, liver function profiles, and alpha-fetoprotein levels from 1984 to 1996.

RESULTS

Sixteen (2.4%) of the 665 subjects were found to be seropositive for HBsAg at birth, and all remained HBsAg-positive at 6 months of age. Twelve of the 16 received long-term follow-up care, and all were confirmed to have chronic HBV infection. Of the 12, 2 had HBeAg seroconversion, and 1 had alanine aminotransferase flares without HBeAg seroconversion. Delayed appearance of hepatitis B core antibody (anti-HBc) occurred in 2 without alanine aminotransferase elevation.

CONCLUSIONS

Current immunoprophylaxis strategy does not protect newborns with surface antigenemia, apparently acquired in utero, from becoming HBV carriers. Immunologic attempts to eliminate HBV may occur in carrier children infected in utero, despite their profound immune tolerance to HBV.

Chronic hepatitis virus infection in children

Hepatitis B and C viruses (HBV and HCV) are the two main hepatitis viruses causing chronic liver diseases in children. In hyperendemic areas, nearly half of the primary infection in chronic HBV carriers occurs during the perinatal period through the transmission from hepatitis B e antigen (HBeAg)-positive mothers. The other half are from horizontal transmission mainly through intrafamilial spread or injection using unsterilized needles. During the natural course of chronic HBV infection, spontaneous HBeAg/anti-HBe seroconversion occurs very rarely (2% annually) before 3 years of age. After 3 years of age, the HBeAg seroconversion rate increases gradually to 5% per year. Those with mothers who are hepatitis B carriers tend to clear HBeAg slower than those whose mothers are non-carriers. Transplacental HBeAg may cause T cell tolerance in infected children. Universal HBV immunization programmes have been effective in reducing the hepatitis B carrier rate more than 10-fold, and the incidence of hepatocellular carcinoma in children has also been decreased significantly. Hepatitis C virus infection occurs mainly in high-risk children, such as those who received blood products (blood diseases, malignancies, post-open heart surgery etc.), children of HCV-infected mothers, and in hyperendemic areas, from injection using unsterile needles. Mother-to-infant transmission occurs on average in 5% of infants of viraemic mothers. The maternal HCV-RNA titre is the most important factor determining the infectivity. Chronicity developed in 60-80% of HCV-infected children. Although transient or persistent elevation of aminotransferases occurs frequently in chronically HCV-infected children, liver histology showed minimal or mild changes only. The most prevalent genotype of HCV in children is Ib. Screening of the blood products for HCV antibody has markedly reduced the rate of HCV infection in children at risk. However, vaccine development is needed to prevent mother-to-infant transmission and other routes of infections.