Yeast-recombinant hepatitis B vaccine. Efficacy with hepatitis B immune globulin in prevention of perinatal hepatitis B virus transmission

CD4+ T cells reverse surface antigen persistence in a mouse model of HBV replication

IMPORTANCE

Hepatitis B virus (HBV) is a leading causative agent of viral hepatitis. A preventative vaccine has existed for decades, but only limited treatment options are available for people living with chronic HBV. Animal models for studying HBV are constrained due to narrow viral tropism, impeding understanding of the natural immune response to the virus. Here, using a vector to overcome the narrow host range and establish HBV replication in mice, we identified the role of helper T cells in controlling HBV. We show that helper T cells promote the B cell's ability to generate antibodies that remove HBV and its associated surface antigen from the blood and that transfer of purified helper T cells from HBV-immunized mice can reverse the accumulation of virus and antigen, furthering our understanding of the immune response to HBV.

Vaccines against SARS-CoV-2 variants and future pandemics

INTRODUCTION

Vaccination continues to be the most effective method for controlling COVID-19 infectious diseases. Nonetheless, SARS-CoV-2 variants continue to evolve and emerge, resulting in significant public concerns worldwide, even after more than 2 years since the COVID-19 pandemic. It is important to better understand how different COVID-19 vaccine platforms work, why SARS-CoV-2 variants continue to emerge, and what options for improving COVID-19 vaccines can be considered to fight against SARS-CoV-2 variants and future pandemics.

AREA COVERED

Here, we reviewed the innate immune sensors in the recognition of SARS-CoV-2 virus, innate and adaptive immunity including neutralizing antibodies by different COVID-19 vaccines. Efficacy comparison of the several COVID-19 vaccine platforms approved for use in humans, concerns about SARS-CoV-2 variants and breakthrough infections, and the options for developing future COIVD-19 vaccines were also covered.

EXPERT OPINION

Owing to the continuous emergence of novel pathogens and the reemergence of variants, safer and more effective new vaccines are needed. This review also aims to provide the knowledge basis for the development of next-generation COVID-19 and pan-coronavirus vaccines to provide cross-protection against new SARS-CoV-2 variants and future coronavirus pandemics.

Hepatitis B infection and risk factors among pregnant women and their male partners in the Baby Shower Programme in Nigeria: a cross-sectional study

OBJECTIVES

To determine the population prevalence and determinants of hepatitis B (Hep B) status, and status discordance, among pregnant women and their male partners in Nigeria.

METHODS

Cross-sectional study assessing the seroprevalence of Hep B virus in a cohort of 16 920 pregnant women and their male partners in northcentral Nigeria. Rapid HBsAg antibody test was used for Hep B diagnosis. Demographic, socio-economic and behavioural information was collected through interviewer-administered questionnaires and evaluated as determinants of Hep B status and couple status discordance using logistic regression.

RESULTS

Of 16 920 participants who had a Hep B test result, 6750 couples and 1316 discordant couples were identified. The prevalence of Hep B among all participants was 10.9%, with lower prevalence among pregnant women (10.2%) than their male partners (11.9%), P < 0.001. The prevalence of Hep B sero-discordance among couples was 19.5% (1316/6750). Younger age, prior Hep B testing and a prior positive Hep B test increased the odds of Hep B infection while being a woman decreased the odds of Hep B among all participants, and among couples. Furthermore, polygamy (adjusted odds ratio [AOR]: 1.49, 95% confidence interval [CI]: 1.19-1.87), prior Hep B testing (AOR: 2.38, 95% CI: 1.14-4.97) and a prior positive Hep B test result were significant determinants of status discordance among the participating couples.

CONCLUSION

The prevalence of Hep B among pregnant women and their male partners in northcentral Nigeria is high. A large-scale intervention is required to reduce Hep B prevalence in this setting.

Recent Progress on the Versatility of Virus-Like Particles

Virus-like particles (VLPs) are multimeric nanostructures composed of one or more structural proteins of a virus in the absence of genetic material. Having similar morphology to natural viruses but lacking any pathogenicity or infectivity, VLPs have gradually become a safe substitute for inactivated or attenuated vaccines. VLPs can achieve tissue-specific targeting and complete and effective cell penetration. With highly ordered epitope repeats, VLPs have excellent immunogenicity and can induce strong cellular and humoral immune responses. In addition, as a type of nanocarrier, VLPs can be used to display antigenic epitopes or deliver small molecules. VLPs have thus become powerful tools for vaccinology and biomedical research. This review highlights the versatility of VLPs in antigen presentation, drug delivery, and vaccine technology.

Hepatitis B vaccine development and implementation

Vaccination against hepatitis B is the most effective strategy to control HBV infection. The first licensed hepatitis B vaccine was developed by the purification of hepatitis B surface antigen (HBsAg) from plasma of asymptomatic HBsAg carriers. Then, the recombinant DNA technology enabled the development of recombinant hepatitis B vaccine. A series of three doses vaccine can elicit long-term protection more than 30 y. Concurrent use of hepatitis B immunoglobulin and hepatitis B vaccine has substantially reduced the mother-to-child transmission of HBV, nearly zero infection in children of carrier mother with negative hepatitis B e antigen (HBeAg) and 5-10% infection in children of HBeAg-positive mothers. By the end of 2018, 189 countries adopted universal hepatitis B vaccination program, which has dramatically reduced the global prevalence of HBsAg in children <5 y of age, from 4.7% in the prevaccine era to 1.3% in 2015. However, the implementation of universal hepatitis B vaccination in some regions is suboptimal and timely birth dose vaccine is not routinely administered in more than half of newborn infants. Optimal worldwide universal hepatitis B vaccination requires more efforts to overcome the social and economic challenges.

Pathogenesis of Non-Zika Congenital Viral Infections

A widespread epidemic of Zika virus (ZIKV) infection was reported in 2015 from South and Central America and the Caribbean. Although the full spectrum of ZIKV infection of the newborn has yet to be determined, other maternal viral infections resulting in transmission to the fetus provide instructive lessons that can be applied to the prospective evaluation of individuals with ZIKV infection. This review focuses on those other congenital infections, including rubella, congenital cytomegalovirus, human immunodeficiency virus, hepatitis B virus, and neonatal herpes simplex virus, from which lessons for the evaluation of ZIKV in the newborn can be applied.

Strategies for the prevention of perinatal hepatitis B transmission in a marginalized population on the Thailand-Myanmar border: a cost-effectiveness analysis

Background

Data on the cost effectiveness of hepatitis B virus (HBV) screening and vaccination strategies for prevention of vertical transmission of HBV in resource limited settings is sparse.

Methods

A decision tree model of HBV prevention strategies utilised data from a cohort of 7071 pregnant women on the Thailand-Myanmar border using a provider perspective. All options included universal HBV vaccination for newborns in three strategies: (1) universal vaccination alone; (2) universal vaccination with screening of women during antenatal visits with rapid diagnostic test (RDT) plus HBV immune globulin (HBIG) administration to newborns of HBV surface antigen positive women; and (3) universal vaccination with screening of women during antenatal visits plus HBIG administration to newborns of women testing HBV e antigen positive by confirmatory test. At the time of the study, the HBIG after confirmatory test strategy was used. The costs in United States Dollars (US$), infections averted and incremental cost effectiveness ratios (ICERs) were calculated and sensitivity analyses were conducted. A willingness to pay threshold of US$1200 was used.

Results

The universal HBV vaccination was the least costly option at US$4.33 per woman attending the clinic. The HBIG after (RDT) strategy had an ICER of US$716.78 per infection averted. The HBIG after confirmatory test strategy was not cost-effective due to extended dominance. The one-way sensitivity analysis showed that while the transmission parameters and cost of HBIG had the biggest impact on outcomes, the HBIG after confirmatory test only became a cost-effective option when a low test cost was used or a high HBIG cost was used. The probabilistic sensitivity analysis showed that HBIG after RDT had an 87% likelihood of being cost-effective as compared to vaccination only at a willingness to pay threshold of US$1200.

Conclusions

HBIG following confirmatory test is not a cost-effective strategy for preventing vertical transmission of HBV in the Thailand-Myanmar border population. By switching to HBIG following rapid diagnostic test, perinatal infections will be reduced by nearly one third. This strategy may be applicable to similar settings for marginalized populations where the confirmatory test is not logistically possible.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2660-x) contains supplementary material, which is available to authorized users.

Seroprevalence of hepatitis B virus serological markers among pregnant Nigerian women

Background:

Chronic hepatitis B infection is a global problem; however, Asia and sub-Saharan Africa are most affected by it. Hepatitis B status of pregnant women is essential for the effective management of the disease and prevention of mother to child transmission.

Materials and Methods:

The study was conducted at the antenatal care unit of four hospitals within Kaduna Metropolis, Nigeria, between August and December 2011. After obtaining ethical clearance, blood samples were collected from 800 consenting pregnant women, the plasma were screened for hepatitis B surface antigen (HBsAg) using first response HBsAg card and the reactive sera were confirmed with enzyme-linked immunosorbent assay. Other serological markers of hepatitis B virus (HBV) were detected using the one-step HBV multi-5 test kit.

Results:

Of the 800 pregnant women screened, 31 (3.9%) tested positive for HBsAg. Only one of the 31 HBsAg positive women had developed the hepatitis B surface antibody, 16 (51.6%) had the envelop antibody, 18 (58.1%) had the hepatitis B core antibody (anti-HBc), and two (6.5%) had hepatitis B envelop antigen (HBeAg). The highest prevalence of HBsAg was recorded among women in age group 21–25 years old (P = 0.968). Similarly, married women (P = 0.772), women in their second trimester of pregnancy (P = 0.938), women with tertiary education (P = 0.972), women from the South-East geopolitical zone (P = 0.250) and those whose husbands were in polygamous relationships (P = 0.944) had the highest seroprevalence of HBsAg.

Conclusion:

HBV was detected with a prevalence of 3.9% among pregnant women in Kaduna Metropolis, Nigeria. About 96.8% (29) of the reactive women had HBeAg negative chronic hepatitis while 6.5% (2) had HBeAg positive chronic hepatitis B infection. About 58.1% of the women had anti-HBc, hence, did not have immunity and probably had chronic infection with reduced risk of vertical transmission. Pregnant women should be screened for HBsAg at the first antenatal clinic visit for appropriate clinical management and effective prevention of vertical transmission.

Prevention of hepatitis B

Hepatitis B virus (HBV) causes life-threatening liver disease. It is transmitted through a horizontal route or a mother-to-infant route, and the latter is the major route in endemic areas. Prevention of HBV infection by immunization is the best way to eliminate HBV-related diseases. The HBV vaccine is the first human vaccine using a viral antigen from infected persons, which is safe and effective. Either passive immunization by hepatitis B immunoglobulin (HBIG) or active immunization by HBV vaccine is effective, and a combination of both yields the best efficacy in preventing HBV infection. The impact of universal HBV immunization is huge, with 90%-95% effectiveness in preventing chronic HBV infection. It is the first cancer preventive vaccine with a protective efficacy against hepatocellular carcinoma (HCC) of ∼ 70%. Nevertheless, further effort is still needed to avoid vaccine failure and to increase the global coverage rate.

Prophylactic vaccination against hepatitis B: achievements, challenges and perspectives

Large-scale vaccination against hepatitis B virus (HBV) infection started in 1984 with first-generation vaccines made from plasma of chronic carriers containing HBV surface antigen (HBsAg). Thereafter, it was replaced in most countries by second-generation vaccines manufactured in yeast cells transformed with gene S encoding HBsAg. Both generations of vaccines have been applied for universal neonate and early childhood vaccination worldwide and have led to a 70-90 % decrease in chronic HBV carrier rates. However, 10-30% of newborns from HBsAg/HBeAg-positive mothers cannot be protected by passive/active vaccination alone and become chronic HBV carriers themselves. Asymptomatic occult HBV infections are frequent even in those who have protective levels of anti-HBs. Suboptimal protection may be due to heterologous HBsAg subtypes that are present in 99% of HBV carriers worldwide. Second-generation vaccines contain partially misfolded HBsAg and lack preS1 antigen that carries the major HBV attachment site and neutralizing epitopes. Third-generation vaccines produced in mammalian cells contain correctly folded HBsAg and neutralizing epitopes of the preS antigens, induce more rapid protection, overcome nonresponse to second-generation vaccines and, most importantly, may provide better protection for newborns of HBV-positive mothers. PreS/S vaccines expressed in mammalian cells are more expensive to manufacture, but introduction of more potent HBV vaccines should be considered in regions with a high rate of vertical transmission pending assessment of health economics and healthcare priorities. With optimal vaccines and vaccination coverage, eradication of HBV would be possible.

Hepatitis B and C in pregnancy: a review and recommendations for care

Our objective was to provide a comprehensive review of the current knowledge regarding pregnancy and hepatitis B virus (HBV) or hepatitis C virus (HCV) infection as well as recent efforts to reduce the rate of mother-to-child transmission (MTCT). Maternal infection with either HBV or HCV has been linked to adverse pregnancy and birth outcomes, including MTCT. MTCT for HBV has been reduced to approximately 5% overall in countries including the US that have instituted postpartum neonatal HBV vaccination and immunoprophylaxis with hepatitis B immune globulin. However, the rate of transmission of HBV to newborns is nearly 30% when maternal HBV levels are greater than 200 000 IU ml(-1) (>6 log10 copies ml(-1)). For these patients, new guidelines from the European Association for the Study of the Liver (EASL) and the Asian Pacific Association for the Study of the Liver (APASL) indicate that, in addition to neonatal vaccination and immunoprophylaxis, treating with antiviral agents such as tenofovir disoproxil fumarate or telbivudine during pregnancy beginning at 32 weeks of gestation is safe and effective in preventing MTCT. In contrast to HBV, no therapeutic agents are yet available or recommended to further decrease the risk of MTCT of HCV, which remains 3 to 10%. HCV MTCT can be minimized by avoiding fetal scalp electrodes and birth trauma whenever possible. Young women with HCV should be referred for treatment post delivery, and neonates should be closely followed to rule out infection. New, better-tolerated treatment regimens for HCV are now available, which should improve outcomes for all infected individuals.

Cost-effectiveness of testing hepatitis B-positive pregnant women for hepatitis B e antigen or viral load

OBJECTIVE

To estimate the cost-effectiveness of testing pregnant women with hepatitis B (hepatitis B surface antigen [HBsAg]-positive) for hepatitis B e antigen (HBeAg) or hepatitis B virus (HBV) DNA, and administering maternal antiviral prophylaxis if indicated, to decrease breakthrough perinatal HBV transmission from the U.S. health care perspective.

METHODS

A Markov decision model was constructed for a 2010 birth cohort of 4 million neonates to estimate the cost-effectiveness of two strategies: testing HBsAg-positive pregnant women for 1) HBeAg or 2) HBV load. Maternal antiviral prophylaxis is given from 28 weeks of gestation through 4 weeks postpartum when HBeAg is positive or HBV load is high (10 copies/mL or greater). These strategies were compared with the current recommendation. All neonates born to HBsAg-positive women received recommended active-passive immunoprophylaxis. Effects were measured in quality-adjusted life-years (QALYs) and all costs were in 2010 U.S. dollars.

RESULTS

The HBeAg testing strategy saved $3.3 million and 3,080 QALYs and prevented 486 chronic HBV infections compared with the current recommendation. The HBV load testing strategy cost $3 million more than current recommendation, saved 2,080 QALYs, and prevented 324 chronic infections with an incremental cost-effectiveness ratio of $1,583 per QALY saved compared with the current recommendations. The results remained robust over a wide range of assumptions.

CONCLUSION

Testing HBsAg-positive pregnant women for HBeAg or HBV load followed by maternal antiviral prophylaxis if HBeAg-positive or high viral load to reduce perinatal hepatitis B transmission in the United States is cost-effective.

The potential of 1018 ISS adjuvant in hepatitis B vaccines: HEPLISAV™ review

Hepatitis B (HBV) virus infects the liver, and upon chronic infection, can cause liver cirrhosis and hepatocellular carcinoma. Despite universal vaccination programs against the virus, HBV still affects over 2 billion people worldwide, with over 240 million developing a chronic infection. While current alum-adjuvanted vaccines have shown efficacy in promoting seroprotection in healthy adults, 5-10% of immune-competent populations fail to achieve long-lasting seroprotection from these formulations. Furthermore, a large proportion of immunocompromised patients fail to achieve seroprotective antibody titers after receiving these vaccines. A novel vaccine candidate, HEPLISAV™, uses immunostimulatory sequences (ISS), in its formulation that helps induce a robust humoral and cell mediated immunity against HBV. In Phase III clinical trials, HEPLISAV™ has been shown to elicit seroprotective antibody titers with fewer immunizations. Similar safety profiles are demonstrated when compared with current HBV vaccines. For these reasons, HEPLISAV™ is an attractive vaccine to combat this global disease.

Hepatitis B virus surface antigen assembly function persists when entire transmembrane domains 1 and 3 are replaced by a heterologous transmembrane sequence

Native hepatitis B surface antigen (HBsAg) spontaneously assembles into 22-nm subviral particles. The particles are lipoprotein micelles, in which HBsAg is believed to span the lipid layer four times. The first two transmembrane domains, TM1 and TM2, are required for particle assembly. We have probed the requirements for particle assembly by replacing the entire first or third TM domain of HBsAg with the transmembrane domain of HIV gp41. We found that either TM domain of HBsAg could be replaced, resulting in HBsAg-gp41 chimeras that formed particles efficiently. HBsAg formed particles even when both TM1 and TM3 were replaced with the gp41 domain. The results indicate remarkable flexibility in HBsAg particle formation and provide a novel way to express heterologous membrane proteins that are anchored to a lipid surface by their own membrane-spanning domain. The membrane-proximal exposed region (MPER) of gp41 is an important target of broadly reactive neutralizing antibodies against HIV-1, and HBsAg-MPER particles may provide a good platform for future vaccine development.

Cellular immunity in children with successful immunoprophylactic treatment for mother-to-child transmission of hepatitis B virus

BACKGROUND

The administration of hepatitis B immunoglobulin followed by hepatitis B vaccine can result in a protective efficacy of almost 90% in mother-to-child transmission of hepatitis B virus (HBV). However, little is known about immunity against HBV infection in children after immunoprophylactic treatment. We tried to assess the association between T-cell responses and viremia in children after successful prophylactic treatment.

METHODS

Thirteen children and their 8 HBV carrier mothers (8 families), who were positive for human leukocyte antigen (HLA)-A24, were enrolled in this study. All of the 13 children received immunoprophylactic treatment and became negative for hepatitis B surface antigen (HBsAg) after birth. HBV-specific cytotoxic T lymphocyte (CTL) responses were evaluated using IFNgamma - enzyme-linked immunosorbent spot (ELISPOT) and major histocompatibility complex class I peptide pentamer assays. Serum HBV DNA was measured by real-time PCR.

RESULTS

Significant HBV-specific T-cell responses were detected in 2 (15%) of the 13 children by ELISPOT. However, the frequency of HLA-A24-HBV-specific CTLs was very low in both HBV carrier mothers and children using pentamers. Of the 13 children, 4 (31%) were positive for serum HBV DNA. However, the levels of serum HBV DNA were 100 copies/ml or less. One of the 2 children in whom significant HBV-specific CTL responses were detectable was positive for serum HBV DNA.

CONCLUSIONS

HBV core and polymerase-specific T-cell responses were detected and a low-dose viremia was observed in children after successful immunoprophylaxis treatment. Although the presence of viremia was not related to HBV-specific T-cell responses, CTLs might play a role in the control of HBV infection in children born to HBsAg-positive mothers after immunoprophylactic treatment.

Global control of hepatitis B virus: does treatment-induced antigenic change affect immunization?

Since its widespread introduction, the hepatitis B vaccine has become an essential part of infant immunization programmes globally. The vaccine has been particularly important for countries where the incidence of hepatitis B virus-related hepatocellular carcinoma is high. Effective treatment options for individuals with chronic hepatitis B infection were limited until 1998 when lamivudine, the first nucleoside analogue drug, was introduced. As a single treatment agent, however, lamivudine has a significant drawback: it induces lamivudine-resistant hepatitis B virus strains that may pose a risk to the global hepatitis B immunization programme. Mutations associated with drug treatment can cause changes to the surface antigen protein, the precise part of the virus that the hepatitis B vaccine mimics. However, the emergence of antiviral drug-associated potential vaccine escape mutants (ADAP-VEMs) in treated patients does not necessarily pose a significant, imminent threat to the global hepatitis B immunization programme. Nonetheless, there is already evidence that current treatment regimens have resulted in the selection of stable ADAP-VEMs. Treatment is currently intended to prevent the long-term complications of hepatitis B virus infection, with little consideration given to potential adverse public health impacts. To address individual and public health concerns, trials are urgently needed to find the optimal combination of existing drugs that are effective but do not induce the emergence of ADAP-VEMs. This paper examines the mechanism of antiviral drug-selected changes in the portion of the viral genome that also affects the surface antigen, and explores their potential impact on current hepatitis B immunization programmes.

Hepatitis B vaccines

Immunization is the most effective way to prevent transmission of HBV and, hence, the development of acute or chronic hepatitis B. The national strategy to eliminate transmission of the virus in the United States includes vaccination of all newborn infants, children, adolescents, and high-risk adults. Postexposure prophylaxis is also advocated, depending on the vaccination and anti-HBs status of the exposed person. Seroprotection after vaccination, defined as anti-HBs > or = 10 mIU/mL, is achieved in over 95% of all vaccinees. The hepatitis B vaccines are very well tolerated with usually minimal adverse effects. Predictors of non-response include increasing age, male gender, obesity, tobacco smoking, and immunocompromising chronic dis-ease. For those who remain nonresponders after the second series of vaccination, adjuvants such as GM-CSF may be considered, but their results are variable.

Genetic and proteomic analysis of the MHC class I repertoire from four ovine haplotypes

Immunity to livestock diseases can be studied directly in the target animal, but its elucidation is often constrained by the lack of major histocompatibility complex (MHC)-defined animals. To address this issue, we have established an MHC-defined sheep resource flock generated around four diverse MHC haplotypes. Initial characterisation of the repertoire of transcribed MHC class I genes identified three class I transcripts associated with each haplotype. Nucleotide sequence, transcript abundance and phylogenetic analysis indicated that they represent alleles at up to four polymorphic loci that vary in number between the different haplotypes. The functional significance of each of these genes is evaluated here using complementary molecular genetic and proteomic approaches. We determine which genes give rise to proteins that localise to the surface of transfected cells. In addition, we provide data to support the generation of expressed products, based on immunoprecipitation of class I products from animals homozygous for each of the four MHC haplotypes followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This provides a clearer picture of the number of MHC class I loci in sheep and allows more rational prediction of their classical (class Ia) or non-classical (class Ib) nature. On the basis of the cellular localisation, phylogenetic and transcriptional analyses, we propose that the ovine MHC comprises a minimum of eight class I loci, with considerable variation between haplotypes.

Outcomes from a Canadian public health prenatal screening program for hepatitis B: 1997-2004

BACKGROUND

Without appropriate prophylaxis, the rate of vertical transmission of hepatitis B virus (HBV) can be as high as 95%. Alberta's provincial prenatal program screens all pregnant women for HBV, and provides prophylaxis to infants born to HBV-infected women. Canadian data on the outcomes of such programs are limited.

METHODS

We conducted a retrospective review of data from pregnant Albertan women who were Hepatitis B Surface Antigen (HBsAg) positive from 1997-2004. We describe the frequency of hepatitis B immunoglobulin (HBIG) and vaccine administration, follow-up serology and pregnancy outcomes.

RESULTS

In total, 1,485 HBsAg-positive pregnant women were identified; an average of 186 women annually (range: 125-216). Of the 980 infants eligible to have completed prophylaxis and serological follow-up, 82.0% were appropriately immunized and serologically tested, 11.3% had complete immunization but no serology testing and 6.6% were incompletely immunized. Of infants with complete immunization and follow-up, 3.7% failed to mount an immune response and 2.1% were infected.

CONCLUSION

A high proportion of infants born to carrier mothers are receiving appropriate post-natal prophylaxis in Alberta. Future research should examine maternal factors that may increase the vertical transmission of HBV.

Performance of a new-generation chemiluminescent assay for hepatitis B surface antigen

BACKGROUND

The usual criteria for analysis of hepatitis B surface antigen (HBsAg) are detection of HBsAg and result confirmation by antibody neutralization. We observed that with the Immulite 2000 HBsAg assay [Diagnostics Product Corporation (DPC)] a relatively high percentage of weakly reactive (WR) samples did not pass the neutralization step.

METHODS

For each of 3 lots of Immulite 2000 HBsAg reagent (DPC), we collected and analyzed HBsAg data from approximately 3000 to 4000 patient blood samples and compared these data with HBsAg data from 3393 samples tested with the Abbott Auszyme assay. For 127 samples with initially WR detection signals (relative signal/cutoff index of 1.00-2.5) on the Immulite 2000 HBsAg assay, we then measured hepatitis B (HB) viral load and/or other HB serologic markers.

RESULTS

The Immulite 2000 HBsAg assay produced more initially reactive results than the Abbott Auszyme method. Many of these reactive samples, however, were WR and did not meet the confirmation criteria in the neutralization test. Moreover, DNA PCR testing indicated that 22 of the 38 WR samples (58%) that did meet the confirmation criteria had no detectable HB viral DNA.

CONCLUSIONS

Immulite 2000 HBsAg assay results include a unique group of WR samples that are associated with both false-positive and false-negative results, regardless of neutralization status, and require careful interpretation. WR HBsAg samples should be reported as confirmed HBsAg reactive only if the samples not only meet the neutralization criteria but also are positive for other HB serologic markers such as anti-HB core total and anti-HB core IgM.

Adherence to the screening program for HBV infection in pregnant women delivering in Greece

Background

Hepatitis B infection (HBV) is a major Public Health Problem.

Perinatal transmission can be prevented with the identification of HBsAg(+) women and administration of immunoprophylaxis to their newborns. A national prevention programme for HBV with universal screening of pregnant women and vaccination of infants is in effect since 1998 in Greece.

Methods

To evaluate adherence to the national guidelines, all women delivering in Greece between 17–30/03/03 were included in the study. Trained health professionals completed a questionnaire on demographic data, prenatal or perinatal screening for HBsAg and the implementation of appropriate immunoprophylaxis.

Results

During the study period 3,760 women delivered. Prenatal screening for HBsAg was documented in 91.3%. Greek women were more likely to have had prenatal testing. HBsAg prevalence was 2.89% (95%CI 2.3–3.4%). Higher prevalence of HBV-infection was noted in immigrant women, especially those born in Albania (9.8%). Other risk factors associated with maternal HBsAg (+) included young maternal age and absence of prenatal testing. No prenatal or perinatal HBsAg testing was performed in 3.2% women. Delivering in public hospital and illiteracy were identifiable risk factors for never being tested. All newborns of identified HBsAg (+) mothers received appropriate immunoprophylaxis.

Conclusion

The prevalence of HBsAg in Greek pregnant women is low and comparable to other European countries. However, immigrant women composing almost 20% of our childbearing population, have significant higher prevalence rates. There are still women who never get tested. Universal vaccination against HBV at birth and reinforcement of perinatal testing of all women not prenatally tested should be discussed with Public Health Authorities.

Evaluation of two chemiluminescent immunoassays of ADVIA centaur for hepatitis B serology markers

BACKGROUND

This study evaluated the performance of 2 Bayer Hepatitis B Chemiluminescent Assays by comparing their performance to the corresponding DPC Immulite 2000 assays.

METHODS

953 samples were tested by both Immulite 2000 and Centaur HBsAg methods; and 75 samples were tested by both Immulite 2000 and Centaur anti-HBc IgM methods.

RESULTS

The overall agreement between Immulite 2000 and ADVIA Centaur anti-HBc IgM assays was 100%. The agreement between Immulite 2000 and Centaur HBsAg assays was 100% for Immulite 2000 positive samples. The overall agreement for HBsAg negative samples was 99.9% after confirmation result was included. However, discrepancy between the 2 assays was observed in 53 samples which were tested initially as "weakly reactive"(index 1.0-1.95) but were not confirmed subsequently by the neutralization test on Immulite 2000. All 53 samples tested negative by Centaur HBsAg assay at the initial run. Furthermore, one Immulite 2000 HBsAg negative sample was reactive and confirmed by Centaur assay.

CONCLUSIONS

While the performance of Bayer Hepatitis B HBsAg and aHBc IgM assays are in good agreement with corresponding DPC assays, the Bayer HBsAg assay is more efficient than the Immulite 2000 assay with its better separation of signal and background noise, and its complete automation features.

Epidemiology and Prevention of Hepatitis B Virus Infection

Hepatitis B is one of the most common infectious diseases globally. It has been estimated that there are 350 million chronic hepatitis B virus (HBV) carriers worldwide. The prevalence of chronic HBV infection varies geographically, from high (>8%), intermediate (2-7%) to low (<2%) prevalence. HBeAg-negative chronic hepatitis B (e-CHB) and occult HBV infection are two special clinical entities, and the prevalence and clinical implications remain to be explored. The predominant routes of transmission vary according to the endemicity of the HBV infection. In areas with high HBV endemicity, perinatal transmission is the main route of transmission, whereas in areas with low HBV endemicity, sexual contact amongst high-risk adults is the predominant route. HBV has been classified into 7 genotypes, i.e. A to G, based on the divergence of entire genome sequence and HBV genotypes have distinct geographical distributions. Three main strategies have been approved to be effective in preventing HBV infection. They are behavior modification, passive immunoprophylaxis, and active immunization. The implement of mass HBV immunization program is recommended by the WHO since 1991, and has dramatically decreased the prevalence of HBV infection and HCC in many countries.

Liver emergencies during pregnancy

Liver disease is an uncommon complication of pregnancy, although one that must be recognized early because of its potential for grave consequences for mother and child. Because of increased awareness and rapid triage of patients, maternal and fetal outcomes have improved significantly over the last 30 years.

Combined passive and active immunoprophylaxis for preventing perinatal transmission of the hepatitis B virus carrier state in Shizuoka, Japan during 1980-1994

BACKGROUND

Efficacy and limits in preventing perinatal infection with hepatitis B virus (HBV) have been examined in a model area in Japan.

METHODS

In Shizuoka (population of 3.6 million), immunoprophylaxis of perinatal HBV infection was started in 1980 in four institutions (Hamamatsu Medical College, Shimada City Hospital, Shizuoka Kodomo Hospital and Numazu City Hospital). Babies born to carrier mothers with hepatitis B e antigen (HBeAg) in serum received hepatitis B immune globulins at birth and 2 months thereafter and vaccines at 2, 3 and 5 months after birth.

RESULTS

Overall, 980 of the 1030 babies born to HBeAg-positive carrier mothers were protected by the immunoprophylaxis during the 15 years from 1980 to 1994 with an efficacy of 95.1%. From 1986 to 1994 while the national immunoprophylaxis was conducted, 329,674 of the 346,637 (95.1%) expectant mothers were tested, and 2081 (0.63%) of them were positive for hepatitis B surface antigen (HBsAg). The immunoprophylaxis was given only to babies born to 764 (36.7%) of the 2081 mothers who tested positive for HBeAg. Of the 494 babies receiving immunoprophylaxis, in whom HBsAg was followed monthly after birth, 462 (93.5%) were protected. The HBV carrier state developed in the remaining 32 (6.5%) babies, 10 of whom (31.3% of the 32) turned positive for HBsAg within 1 month after birth, most likely owing to infection in utero.

CONCLUSIONS

Passive-active immunoprophylasxis of high-risk babies was highly efficacious in preventing perinatal transmission of the HBV carrier state. Most failures (approximately 70%) occurred in the high-risk babies who were exposed to HBV after birth, and would have been avoided by careful and extensive execution of the immunoprophylaxis.

Antibody response to postexposure prophylaxis in infants born to hepatitis B surface antigen-positive women

BACKGROUND

Annually 20,000 infants are born to hepatitis B surface antigen (HBsAg)-positive US women. Without prophylaxis 30% risk chronic hepatitis B virus infection, and 25% of those risk dying from resulting liver cirrhosis or liver cancer as adults.

METHODS

We attempted to interview each HBsAg-positive pregnant woman reported to the health department between 1992 and 1997, to provide their infants with immunoprophylaxis at birth and in the clinic or home and to serotest at 9 to 15 months of age.

RESULTS

Of 879 women reported, 92% enrolled; 787 delivered 796 live infants; 91% of infants received hepatitis B immunoglobulin; 98, 95 and 89% received hepatitis B vaccine (HepB) Doses 1, 2 and 3, respectively; and 80% were serotested. Of these 2.2% were HBsAg-positive and 97% had antibody to HBsAg (anti-HBs) of > or =10 mIU/ml. Anti-HBs concentrations measured in 504 infants were 10 to 99 mIU/ml (25%), 100 to 999 mIU/ml (43%) and > or =1000 mIU/ml (29%). Serotesting was less likely among infants of mothers <20 years of age [odds ratio (OR) 2.5]; white, non-Hispanic (OR 2.8); or with a household income of <$15,000/year (OR 2.0). Lower antibody titers were found when serotesting at 4 to 12 months than at <4 months after HepB-3 (OR 1.8 to 4.4), with HepB-3 receipt <6 months after HepB-2 (OR 2.5) and when household income was <$15,000/year (OR 2.1).

CONCLUSIONS

Centralized case management with home visits resulted in high rates of complete immunoprophylaxis and postvaccination testing among infants born to HBsAg-positive women. Perinatal immunoprophylaxis was immunogenic under routine public health use, with higher anti-HBs titers occurring in infants tested <4 months postvaccination. Because infants in households with low income had higher rates of nonprotective antibody responses, they may benefit from extra efforts to ensure that serotesting is conducted postvaccination.

The virological and clinical significance of mutations in the overlapping envelope and polymerase genes of hepatitis B virus

The potential for hepatitis B virus (HBV) to alter its genome is considerable. This occurs because the virus utilizes a reverse transcription step in replicating the viral genome. Like human immunodeficiency virus, the reverse transcriptase of HBV is error prone and as a consequence of specific selection pressures within a host a population of viral quasispecies emerges. HBV mutants with survival advantages over the wild type virus appear within the selective in vivo environment. Some of these viruses include HBV vaccine escape and anti-viral resistant mutants that have changes in the envelope (S) and polymerase genes, respectively. In addition, the genome of HBV is organised in to overlapping reading frames. The S gene is completely overlapped by the polymerase gene. As a consequence, mutations in the S gene may produce changes in the overlapping polymerase gene. Similarly, mutations in the polymerase gene may produce changes in the S gene. The virological and clinical significance of such overlapping mutations is unclear. However, we have shown that certain mutations in either the S or polymerase gene produce functionally significant changes in the respective overlapping gene. Treatment of chronic hepatitis B carriers with long-term lamivudine (LMV) results in the selection of HBV mutants that are resistant to this nucleoside analogue. The polymerase mutations associated with LMV resistance produce changes in the overlapping S gene and in its envelope protein (hepatitis B small antigen, HBsAg) that results in a reduced antigenicity of the HBsAg protein. The selection of vaccine escape mutants by HBV vaccination or hepatitis B immune globulin is associated with changes in the S gene that are accompanied by mutations in the fingers sub-domain of the polymerase protein. When combined with polymerase mutations that are associated with resistance to LMV the changes within the fingers sub-domain of the viral enzyme behave as compensatory mutations that are able to restore the replication of LMV resistant HBV. The ability to change a viral protein by mutations in an overlapping but unrelated viral gene may produce HBV mutants with altered antigenicity and/or replication and a natural history that may be distinctly different to wild type HBV.

Chronic hepatitis B: current and future treatment options

Hepatitis B, a major viral infection that can lead to cirrhosis and hepatocellular carcinoma, is the ninth most common cause of death worldwide. Prevention of hepatitis B virus transmission is key to reducing the spread of this serious condition. Management of chronic hepatitis B requires significant knowledge of approved pharmacotherapeutic agents and their limitations. Today, agents approved by the Food and Drug Administration for this infection are interferon-alpha-2b and lamivudine. Newer agents are being developed and hold promise: adefovir, famciclovir, ganciclovir, lobucavir, entecavir, emtricitabine, L-deoxythymidine, clevudine, a therapeutic vaccine, and thymosin alpha-1. Therapeutic options for managing hepatitis infection after liver transplantation are also evolving. These include hepatitis B immunoglobulin and nucleoside analogues.

Considerations for hepatitis B as part of a combination vaccine

BACKGROUND

In 1991 the Advisory Committee on Immunization Practices (ACIP) developed a comprehensive strategy to eliminate the transmission of hepatitis B virus in the United States, which includes immunization of all infants. Today, as the number of recommended childhood vaccinations increases, combination vaccines are needed to simplify the immunization schedule and improve coverage levels.

METHODS

A review of the literature was performed to determine the considerations that should be taken when hepatitis B virus vaccine (HepB) is included as part of a combination vaccine.

RESULTS

A combination vaccine that incorporates HepB and other routine infant vaccine antigens has been developed for administration at 2, 4 and 6 months of age. Clinical studies have demonstrated that administration of HepB, either as a monovalent or combination vaccine at 2, 4 and 6 months of age, induces a seroprotective immune response similar to that achieved with monovalent HepB administered at 0, 1 and 6 months of age. In addition the combination vaccine results in similar or fewer adverse reactions compared with separate administration of its components. Infants given a dose of monovalent HepB at birth will receive a total of four doses of HepB when the combination is used. The extra dose of HepB has not led to increased adverse reactions.

CONCLUSIONS

A HepB-containing combination vaccine administered at 2, 4 and 6 months of age is as safe and immunogenic as separate administration of its components and will help simplify the childhood immunization schedule.

Safety of neonatal hepatitis B vaccine administration

OBJECTIVE

To determine whether hepatitis B vaccination of newborns increases the incidence of fever and/or suspected sepsis.

METHODS

A prospective clinical study was undertaken at the Kaiser Permanente San Francisco Medical Center involving normal full term newborns born between November 1, 1991, and April 30, 1994. During this time 3302 infants were vaccinated within 21 days of birth with hepatitis B vaccine, and 2353 were not. Clinical and demographic data were collected from Kaiser Permanente's existing clinical information systems, and laboratory data for blood and cerebrospinal fluid (CSF) cultures were obtained from the comprehensive automated regional laboratory reporting system.

RESULTS

There were no significant differences between vaccinated and unvaccinated newborns in the proportion of infants who received care for fever (0.8% vaccinated and 1.1% unvaccinated, P = 0.28), allergic reactions, seizures or other neurologic events in the first 21 days of life. Vaccinated newborns were significantly less likely to undergo microbiologic evaluation for possible sepsis. Among vaccinated newborns 4.0% had blood cultures and 1.6% had CSF cultures. Among infants who were not vaccinated 8.3% had blood cultures and 1.6% had CSF cultures (P <0.001 for both tests).

CONCLUSION

This study found no evidence that newborn hepatitis B vaccination is associated with an increase in the number of febrile episodes, sepsis evaluations or allergic or neurologic events. In addition our data did not support any increase in medical procedures attributed to receipt of hepatitis B vaccine.

A multi-center controlled study of rapid hepatitis B vaccination using a novel triple antigen recombinant vaccine

Hepatitis B vaccines have been available for 20 years, however, the disease still remains a global problem. Clearly, the protection of at-risk groups could be improved if a more potent vaccine with a shorter vaccination regimen were available. Hepacare is new recombinant vaccine, which contains three of the surface antigens of the HB virus and has higher immunogenicity than present single antigen (HBsAg only) vaccines. This study evaluates the potential for developing seroprotection rapidly and the viability of a 1 month/two dose regimen. A total of 400 adult subjects were vaccinated using either the present accelerated 2 month/three dose regimen of Engerix-B or a 1 month/two dose regimen of a novel triple antigen vaccine (Hepacare). Both vaccines were well tolerated. Four weeks after a single dose, the seroprotective rates for Engerix-B and the triple antigen vaccine were 5 and 17%, respectively. By month 2, 4 weeks after two doses of vaccine, it was 38 and 61%. Finally by month 3, 4 weeks after a third dose of Engerix-B or placebo, respectively, the seroprotection rates were 71 and 82%. The geometric mean titres (GMTs), of these responders was then 119 and 120 IU/l, respectively. Both vaccines were well tolerated. At all points up to and including 3 months after beginning vaccination, the novel 1 month/two dose regimen of Hepacare was significantly more effective in producing seroporotective titres than the 2 month/three dose regimen of Engerix-B (P = 0.001).

Update on chronic viral hepatitis

Many recent and significant advances in the field of chronic viral hepatitis, including therapy, suggest that an update on chronic hepatitis is timely. Chronic hepatitis B virus infection remains a significant worldwide cause of liver cirrhosis and hepatocellular carcinoma, despite the wide availability of a long established and effective vaccine. Transmission occurs via perinatal, sexual, and parenteral routes (particularly intravenous drug abuse and although blood products still carry a risk, this is now extremely low in Western countries). Only a minority of infected adult cases develop chronic hepatitis but in children under 1 year, 90% develop chronic hepatitis. The clinical spectrum of chronic liver injury ranges from mild inflammation to end stage liver cirrhosis. Interferon alfa has been the mainstay of treatment for patients with active disease but nucleoside analogues (lamivudine and adefovir) are now available with similar efficacy. Patients with end stage liver disease and hepatocellular carcinoma can be offered transplantation but infection in the graft is commonplace. The combination of hepatitis B immunoglobulin and newer antiviral drugs reduce the incidence and severity of graft infection significantly. The hepatitis C virus epidemic of the latter half of the 20th century now affects more than 1% of populations worldwide. This RNA virus is spread parenterally and is becoming the leading indication for liver transplantation. The majority of patients develop chronic hepatitis, which may be progressive, evolving to significant liver disease (cirrhosis or hepatocellular carcinoma) in about 20% cases after decades. Treatment with the combination of interferon alfa and ribavirin is successful in up to 40% cases. Liver transplantation is a therapeutic option for some but graft infection is universal and often complicated by progressive liver fibrosis. A vaccine remains a remote prospect so that prevention is crucial. Hepatitis D virus infection occurs on a background of hepatitis B virus infection and can also cause liver damage. The response to antiviral therapy is poor. The newer "hepatitis" viruses G and TT do not cause significant liver injury.

Anti-HBs characteristics after hepatitis B immunisation with plasma-derived and recombinant DNA-derived vaccines

Hepatitis B surface antigen derived from chronic hepatitis B carriers has been replaced almost completely by recombinant DNA-derived HBsAg for use as hepatitis B vaccine. Similarly, recombinant DNA-derived HBsAg is replacing plasma-derived HBsAg in standard anti-HBs assays. We analysed the influence of a change from plasma-derived HBsAg to recombinant DNA-derived HBsAg on antigen presentation in immunoassays and the characteristics of the anti-HBs antibodies after immunisation. Antigens and/or antibodies were subjected to three types of experiments: (a) binding of 'a'-loop specific monoclonal (anti-S) antibody conjugates to immobilised vaccine-HBsAg; (b) binding of post-vaccination anti-HBs to immobilised (vaccine-)HBsAg and (c) inhibition of HBsAg binding to immobilised monoclonal anti-HBs after pre-incubation with post-vaccination antibodies. Our results show that, in both antigen presentation and anti-HBs binding properties, yeast recombinant HBsAg and related antibodies could be clearly distinguished from plasma-derived HBsAg and related antibodies. Divergent results were also obtained in the inhibition assay with recombinant DNA-derived HBsAg but not with serum HBsAg from the vaccine HBsAg subtype. It is concluded that both antigen presentation in vaccines and in anti-HBs assays can markedly influence the quantitation anti-HBs response. It is suggested that a challenge with an heterologous hepatitis B virus may encounter reduced efficacy of vaccine antibodies.

Progress in coverage with hepatitis B vaccine among US children, 1994-1997

OBJECTIVES

This study was done to assess progress in hepatitis B vaccination of children from 1994 through 1997.

METHODS

We used data from the National Immunization Survey (NIS), a random-digit-dialed telephone survey that includes a mail survey to verify vaccination providers' records. The NIS is conducted in 78 geographic areas (50 states and 28 selected urban areas) in the United States.

RESULTS

A total of 32,433 household interviews were completed in the 1997 NIS. An estimated 83.7% of children aged 19 to 35 months received 3 or more doses of hepatitis B vaccine. Coverage with 3 doses was greater (86.7%) among children in states that had day care entry requirements for hepatitis B vaccination than among children in states without such requirements (83.0%) and was greater among children from families with incomes at or above the poverty level (85.0%) than among children below the poverty level (80.6%). Hepatitis B vaccination of children increased from 1994 through 1996, from 41% to 84%, but coverage reached a constant level of 84% to 85% in 1996/97.

CONCLUSION

Although substantial progress has been made in fully vaccinating children against hepatitis B, greater efforts are needed to ensure that all infants receive 3 doses of hepatitis B vaccine.

Unexplained fever in neonates may be associated with hepatitis B vaccine

AIM

To investigate whether hepatitis B vaccination has increased the number of cases of unexplained neonatal fever.

METHOD

The files of all infants born from 1 January 1991 to 31 December 1992, in whom a diagnosis of "injected antibiotic" or "disease of temperature regulation" was recorded, were reviewed. Those who had unexplained fever of 38 degrees C or higher during the first three days of life were divided into two groups: infants who did not receive the hepatitis B vaccine (1991) and infants who did (1992).

RESULTS

In 1992 the incidence of unexplained fever in hepatitis B vaccinated neonates was significantly higher than in the 1991 group of pre-vaccination neonates (35 out of 5819 (0.6%) vs 14 out of 5010 neonates (0.28%) respectively, p=0.013).

CONCLUSIONS

The increase in the number of cases of unexplained neonatal fever seems to be associated with the introduction of routine hepatitis B vaccination on the first day of life. The possibility that an excess number of neonates will undergo unnecessary procedures and treatment to diagnose unexplained fever justifies planning a controlled study to determine whether these preliminary findings point to a significant problem.

Comparative safety of two recombinant hepatitis B vaccines in children: data from the Vaccine Adverse Event Reporting System (VAERS) and Vaccine Safety Datalink (VSD)

BACKGROUND

Preliminary review of data from the Vaccine Adverse Event Reporting System (VAERS), 1991-1994, revealed that more serious adverse events were reported in children who received a specific brand of recombinant hepatitis B (HepB) vaccine.

OBJECTIVE

To compare the post-marketing safety experience of the two recombinant HepB vaccines licensed for use in infants and children in the United States.

DESIGN

Review of a case series derived from passive surveillance data in the national VAERS. A retrospective cohort study using data from one health maintenance organization participating in Vaccine Safety Datalink (VSD), a computerized record linkage system. POPULATIONS STUDIED: U.S. children, ages birth-10 years for whom adverse events after HepB vaccine were reported to VAERS, 1991-1994. Children, ages birth-6 years, who received HepB vaccine at Kaiser Permanente Medical Care Program, Northern California, 1991-1994.

MAIN OUTCOME MEASURES

VAERS reporting rates for each vaccine by manufacturer were calculated from the numbers of reported events occurring within 30 days of HepB vaccination and the number of doses distributed by the manufacturers. VSD event rates for each vaccine were calculated from the numbers of hospitalization or emergency room visits within 30 days of HepB vaccination and the number of vaccine doses administered to the cohort.

RESULTS

In VAERS, higher rates of serious events (i.e., life threatening or resulting in hospitalization or permanent disability) were reported in children who received Vaccine A vs. Vaccine B (relative risk [RR]: 3.13-8.18, P < 0.01), particularly by those vaccinated in the private (RR: 7.62-28.58, P < 0.01), but not public sector (RR: 2.12, P = 0.19). Similar types of events were reported in recipients of both vaccines. In contrast, analysis of VSD data showed no significant difference in rates of hospitalization or ER visits in children who received either HepB vaccine (RR: 0.96-1.25, P > 0.05).

CONCLUSIONS

Our investigation reveals that it is unlikely there is a true difference between rates of serious events temporally associated with the two HepB vaccines in children. This study demonstrates the dual roles played by VAERS and VSD in providing a more complete picture of the post-marketing safety profile of childhood vaccines, and underscores the importance of using other analytic studies to evaluate findings from passive surveillance systems of adverse events.

Ten-year neonatal hepatitis B vaccination program, The Netherlands, 1982-1992: protective efficacy and long-term immunogenicity

From 1982 to 1989, 705 infants born to HBsAg-positive mothers entered the Dutch neonatal hepatitis B vaccination program and received passive-active hepatitis B immunization in three randomized controlled trials testing variations in time of starting active vaccination, dose and type of vaccine, and number of hepatitis B immunoglobulin (HBIg) injections. A meta-analysis of individual patient data of the three randomized trials was performed to determine which independent host and vaccination related factors influence protective efficacy and long-term immunogenicity, and to assess whether hepatitis B vaccination concomitant with standard DKTP vaccination provides optimal protection. Statistical methodology included multivariate logistic regression analysis. Eight infants (1.1%), all born to HBeAg-positive mothers, became HBsAg carriers within the first year of life. The protective efficacy rate (PER) of passive-active immunization at 12 months follow-up was 92% for the total group of children from 114 HBeAg-positive mothers with no significant differences between children starting active immunization at birth or at 3 months of age, between infants starting at 3 months of age receiving one or two doses of HBIg or between those receiving plasma derived or recombinant vaccine. The only factor that affected the PER significantly was the level of maternal HBV DNA; PER was 100% if maternal HBV DNA was < 150 pg ml-1 and 68% for HBV DNA levels > 150 pg ml-1. After 5 years of follow-up, the group that started active immunization at birth had significantly more infants with loss of seroprotection (anti-HBs levels < 10 IU l-1, 15%) than the corresponding group starting at 3 months of age (anti-HBs < 10 IU l-2, 2%). One of 35 children with loss of seroprotection at 2 years became a HBsAg carrier in the fifth year of follow-up. This meta-analysis shows that the protective efficacy of passive-active hepatitis B vaccination is mainly influenced by material HBV DNA levels, and independent of the time of starting active vaccination at birth or at 3 months of age; long-term immunity was enhanced by starting active vaccination concomitant with DKTP vaccination. These findings allow incorporation of hepatitis B vaccine into the standard infant immunization programs for countries with a passive-active immunization strategy for the control of hepatitis B. Additional measures are needed to protect neonates of highly viremic women.

Hepatitis in the obstetric patient

The six agents identified thus far that cause viral hepatitis are reviewed, and their impact upon pregnancy is described. Although it is the most common cause of jaundice during pregnancy, viral hepatitis does not generally increase the risk of pregnancy complications, nor is it teratogenic. Vertical transmission of some types of viral hepatitis does occur, however.

Recombinant hepatitis B vaccination of neonates and infants: emerging safety data from the Vaccine Adverse Event Reporting System

OBJECTIVES

To evaluate the postmarketing safety of recombinant hepatitis B (HB) vaccine given to neonates and infants in the US.

METHODS

US reports associated with HB vaccination and received between January 1, 1991, and May 31, 1995, by the national Vaccine Adverse Events Reporting System (VAERS) were reviewed as a case series.

RESULTS

During 1991 through 1994, 12,520 (32%) VAERS reports were received for events temporally associated with administration of HB vaccine, of which 14% were received for neonates and infants. More reports described serious outcomes for neonates (< 0.1 year old) than for other age groups (40% vs. 6 to 15%). HB alone was administered to 58 (97%) neonates; review of these reports did not reveal unexpected serious events. Among infants (0.1 to 0.9 years old) 192 (9%) received HB vaccine alone and 1469 (66%) received HB in combination with diphtheria-tetanus-pertussis (DTP) vaccine. Similar serious adverse events reported in neonates and infants included fever, agitation and apnea. Events reported for infants receiving HB/DTP and DTP alone were similar and differed from reports filed for infants receiving HB vaccine alone, suggesting that these events may be associated with use of DTP vaccine.

CONCLUSIONS

This review shows no unexpected adverse events in neonates and infants given HB vaccine despite use of at least 12 million doses of vaccine given in these age groups. Although VAERS lacks the ability to distinguish coincidental events from true vaccine reactions, this database represents the largest case series of events temporally associated with HB vaccination of neonates and infants.

Ante-natal screening for hepatitis B surface antigen: an appraisal of its value in a low prevalence area

The costs and projected benefits of universal screening for hepatitis B virus (HBV) infection in pregnant women in East Anglia are calculated and compared with current practice. By adjusting data from West Midlands region for ethnicity, the prevalence of maternal hepatitis B surface-antigen (HBsAg) positivity in East Anglia is predicted to be 0.083% (1 in 1200). Published data on health risks of perinatal HBV infection and on immunisation efficacy are used to derive benefits of screening. The marginal direct cost of screening is identified from regional sources. Current clinical practice in East Anglia identifies 7 surface-antigen positive mothers per year, whereas 22 are expected. Routine antenatal screening in East Anglia would prevent 2.6 additional childhood carriers per year (compared with current practice), resulting in the prevention of 0.7 deaths per year occurring 40-50 years in the future. The direct cost per (undiscounted) life-year saved would be Pounds 2437, not including savings on treatment for chronic hepatitis B infection. Routine prenatal screening for maternal HBsAg should be introduced without delay and continue even if HBV vaccination is introduced into the UK childhood immunisation schedule.

Comparative safety and immunogenicity of two recombinant hepatitis B vaccines given to infants at two, four and six months of age

OBJECTIVES

To evaluate the relative safety and immunogenicity of the two recombinant hepatitis B vaccines licensed in the United States with doses recommended for routine immunization of low risk infants and a schedule that corresponds with routine pediatric visits.

METHODS

Healthy infants were immunized at 2, 4 and 6 months of age with hepatitis B vaccine manufactured by either SmithKline Beecham (Engerix-B, 10 micrograms/dose, n = 228) or Merck and Co. (Recombivax HB, 2.5 micrograms/dose, n = 200). Adverse reactions were ascertained by parental reports and interviews and by review of medical records. Antibody concentrations to hepatitis B surface antigen (anti-HBs) were measured in sequential serum specimens by enzyme immunoassay.

RESULTS

Adverse reactions were mild and the rates were not significantly different between the two groups. After the first and second doses the rates of seropositivity (> or = 10 mIU/ml) and seroprotection (> or = 10 mIU/ml) were significantly higher in infants given SmithKline Beecham vaccine (P < 0.01). After the second and third doses infants given SmithKline Beecham vaccine also had significantly higher geometric mean anti-HBs concentrations compared with those given Merck vaccine (348.0 mIU/ml vs. 66.9 and 1914.8 mIU/ml vs. 514.8 mIU/ml, respectively, P < 0.001). Nevertheless after the third dose 99% of infants in both vaccine groups achieved seroprotective antibody concentrations.

CONCLUSIONS

Both recombinant hepatitis B vaccines were safe and immunogenic when administered concurrently with other pediatric vaccines at 2, 4 and 6 months of age, but earlier protective responses were observed with the SmithKline Beecham vaccine than with the Merck vaccine.

Safety and immunogenicity of a recombinant hepatitis B vaccine administered to infants at 2, 4 and 6 months of age. The Kaiser-UCLA Vaccine Study Group

A recombinant hepatitis B vaccine was administered to over 5000 infants in a prospective, randomized and blinded study. Infants were given either recombinant hepatitis B vaccine (Engerix-B, SmithKline Beecham Pharmaceuticals, 10 micrograms dose-1) or a Haemophilus influenzae type b (Hib) conjugate vaccine at 2, 4 and 6 months of age simultaneously with diphtheria-tetanus-pertussis and oral polio vaccines. Adverse reactions were ascertained by parental reports and interviews, and review of medical records. Blood specimens collected from 269 infants given hepatitis B vaccine were assayed for antibody to hepatitis B surface antigen (anti-HBs) by enzyme immunoassay. Infants given hepatitis B vaccine experienced low rates of adverse reactions that were similar or lower than the rates in infants given Hib conjugate vaccine. The geometric mean anti-HBs concentrations were 9.6 mIU ml-1 after one dose, 333 mIU ml-1 after two doses and 1812 mIU ml-1 after three doses (99% had levels > or = 10 mIU ml-1). Antibody responses to diphtheria and tetanus toxoids were unaffected by simultaneous administration of hepatitis B or Hib conjugate vaccine. Engerix-B vaccine was safe and immunogenic when given with other routine childhood immunizations at 2, 4 and 6 months of age, and should provide long-term protection against hepatitis B virus infection.

Prevalence study of different hepatitis markers among pregnant Albanian refugees in Greece

Aim of the study was to record the prevalence of the various types of viral hepatitis, especially hepatitis B, in pregnant Albanian refugees in Greece. The study comprised 500 pregnant refugees of mean age 25.1 +/- 4.6 years. In Albania, all women had lived in overcrowded houses and had been exposed to non throw-away needles and syringes. Various indices for all hepatitis types were determined. The prevalence of HBsAg was 13.4%, of anti-HBs 53%, of total anti-HBc 70.8%, of anti-HBc IgM 0.4%, of HBeAg 1.2%, of anti-HBe 58.6%, of anti-HAV 96.2%, of anti-HAV IgM 1%, of anti-HDV 0.4%, of anti-HCV 0.6% and of anti-HEV 2%. HBeAg was found positive in 7.5% of HBsAg carriers. Prevalence of hepatitis B markers, as determined by HBsAg and/or anti-HBs and/or total anti-HBc was significantly higher in those with a history of previous hospitalization in Albania (p = 0.01) and those with previous history of hepatitis (p = 0.02). The high prevalence of hepatitis B markers in pregnant Albanian refugees proves that HBV infection is highly endemic in Albania and the possibility of perinatal transmission to the offsprings urges for HBV vaccination programmes. On the other hand improvements in the socioeconomic conditions and the sanitation system in Albania is anticipated to reduce the incidence of HAV and HBV infections.

Comparative study of the immunogenicity and safety of Engerix-B administered at 0, 1, 2 and 12 months and Recombivax HB administered at 0, 1, and 6 months in healthy adults

A randomized trial compared the safety and immunogenicity of Engerix-B (EB) 20 micrograms administered intramuscularly (IM) at 0, 1, 2, and 12 months with Recombivax HB (RHB) 10 micrograms administered IM at 0, 1, and 6 months in healthy adults. At months 3 and 6, significantly more subjects who received EB were seroprotected compared to those who received RHB (84 vs 67%, p = 0.0027; 95 vs 76%, p < 0.001, respectively). SP rates were similar between the vaccination groups approximately 1 year after administration of the initial dose (91 and 83%, respectively; p = 0.1). The vaccines were well tolerated with injection site pain being the most commonly reported adverse event.

Risks and benefits of interferon-alpha in the treatment of hepatitis

The high worldwide prevalence of chronic viral hepatitis, as well as its progressive course, have led to the performance of multiple clinical studies. The natural history of the disease is different depending on the infecting virus; thus, the evolution to liver cirrhosis and/or hepatocellular carcinoma for the hepatitis B, C and delta (D) viruses in chronic hepatitis is 15, 20 and 75%, respectively. Different therapeutic agents have been used in attempts to modify the natural course of these diseases, interferon-alpha (IFN alpha) having proved to be the most effective. In 30 to 50% of patients, treatment with IFN alpha has achieved inhibition of viral replication, as well as normalisation of aminotransferase levels. Moreover, in a majority of patients, histological improvement is observed, principally in piece-meal necrosis and portal inflammation. The dosage currently recommended for treatment of chronic hepatitis B is 30 to 35MU weekly for a minimum of 4 months; when there is a co-existing delta virus infection, the total dosage employed should be greater. For hepatitis C, the minimum effective dosage is 9MU weekly, and a treatment duration of 12 months is recommended. The administration of IFN alpha produces a series of dose-dependent adverse effects, which are reversible on suspension of the medication. The most frequent of these adverse reactions is the 'flu-like' syndrome, which is self-limited and generally well tolerated. Secondary haematological alterations (leucopenia and thrombocytopenia) are the most frequent cause of reduction in dosage or suspension of treatment, although the latter is not normally necessary. The proportion of patients requiring dosage modification or suspension of treatment fluctuates between 5 and 15%. Taking the evolution of chronic hepatitis into account, there can be no doubt that all patients with this disease should be offered treatment. At present, the drug of choice is IFN alpha, as it slows disease progression and it is generally well tolerated.

Immunogenicity of two different dosages (10 and 5 micrograms) of recombinant DNA hepatitis B vaccine in healthy neonates

The immunogenicity of a half (5 micrograms) and a full (10 micrograms) dosage of recombinant DNA yeast-derived hepatitis B vaccine (HB-Vax-DNA) in healthy neonates was assessed in order to compare two candidate dosages of vaccine. After randomization 174 newborns of HBsAg-negative mothers entered the study. Neonates received four doses of either 10 or 5 micrograms hepatitis B vaccine, according to the DTP-polio immunization schedule at months 3, 4, 5 and 11. No serious adverse reactions were observed; 15.5% of vaccinated newborns suffered mild transient local symptoms. The vaccine was highly immunogenic irrespective of dosage of vaccine; all infants developed anti-HBs levels > or = 10 IU l-1, 99% > or = 100 IU l-1. A dosage of 10 micrograms hepatitis B vaccine produced higher antibody levels than 5 micrograms hepatitis B vaccine after primary vaccination (first three doses) but not after booster vaccination (fourth dose) (p = 0.06 and 0.75, respectively). Either vaccine dosage can be recommended for incorporation in the Expanded Programme on Immunization in the Netherlands.

Hepatitis B control in China: knowledge and practices among village doctors

OBJECTIVES

To guide development of a hepatitis B control program in China, we investigated village doctors' sterilization practices, injection use, vaccination levels, and knowledge and counseling skills.

METHODS

The head doctor from each village health station in a rural county (n = 260) completed a self-administered questionnaire.

RESULTS

Of the respondents, 94.2% reported adequate sterilization of needles; however, inadequate sterilization of syringes and acupuncture needles was common. Injections were found to be frequent and profitable. Of head doctors, 16.2% reported that most infants in their villages are vaccinated against hepatitis B. There was very high knowledge of modes of hepatitis B transmission, but it was not used to formulate advice for a hypothetical carrier. Knowledge of the consequences, prevalence, and use of condoms to prevent sexual transmission was lower.

CONCLUSIONS

The sterilization of acupuncture needles, reuse of syringes, and frequent injections are practices that may transmit the hepatitis B virus. Research into issues of vaccine acceptance is needed to expand immunization. A review of treatment practices and better training in counseling for village doctors is suggested.

Increased seroprevalence of hepatitis B in dental personnel necessitates awareness of revised pediatric hepatitis B vaccine recommendations

This article presents data regarding occurrence of hepatitis B in health care workers and children living in their households. Also reviewed are recent revisions in pediatric hepatitis B vaccine recommendations. The purpose of this discussion is twofold: to provide information to assist dental personnel in the decision-making process regarding vaccination of infants, children, and adolescents in their households; and to increase knowledge to facilitate educational presentations. In the United States from 1979 to 1989 the prevalence of new acute hepatitis B cases increased by 37 percent. An estimated 1.25 million people with chronic hepatitis B are capable of infecting those within their immediate environment, including their families. Studies indicate that dental health care workers, through occupational exposure, may have a 10 times greater risk of becoming a chronic hepatitis B carrier than the average citizen. The World Health Organizations's Expanded Programme on Immunizations recommends that children receive vaccination in populations where hepatitis B is prevalent. The three-pronged approach for reducing pediatric transmission includes: (1) vaccination of infants born to infected mothers, (2) routine vaccination of children born to hepatitis-seronegative mothers, (3) identification and vaccination of specific groups of adolescents. Comprehension of these changes may increase compliance regarding vaccination of children in our household, as well as enhancing our educational presentations to patients, the community, and professional societies.