Age- and sex-related study of hepatitis B virus chronic carrier state in infants from an endemic area (Senegal)

This report concerns hepatitis B virus (HBV) infections observed in 155 infants from Senegal, studied with a view to determining the factors involved in development of the chronic carrier state. A chronic carrier state was observed in 50.3% of the infants. This study confirms that the risk of chronic carriage is linked to age. This risk declines very rapidly with age, falling from 82% in infants under 6 months old, to 15% in children between the ages of 2 and 3 years. Spontaneous elimination of hepatitis B surface antigen (HBsAg) is uncommon in HBsAg carriers during childhood. The difference observed in chronic carriage between males and females is due to a difference in susceptibility of the two sexes to the development of the chronic carrier state: HBV infections (before 2 years of age) lead to a chronic carriage in 77% of males as against 50% of females. These conclusions are important in view of the immunisation programs being carried out against hepatitis B virus in endemic areas. For a maximum efficacy, vaccination must be carried out at birth, or shortly afterwards.     

A study on the perinatal transmission of the hepatitis B virus

The purpose of this study was to determine the age wise prevalence of Hepatitis B virus (HBV) in children under five years and to analyze the relative importance of horizontal or vertical transmission. This study included 400 children in the age group of less than five years attending the outpatient department of pediatrics with minor complaints. History of HBV immunization was taken as the exclusion criteria. All the samples were tested for Hepatitis B surface antigen (HBsAg) and anti HBs using commercial ELISA kits. Liver function tests were performed on all the HBsAg positive patients. Hepatits B nucleocapsid antigen (HBeAg) was detected in few HBsAg positive mothers. Overall HBsAg positivity in children below five years was 2.25%. There was no statistically significant difference in HBsAg positivity in the different age groups by chi square test. HBsAg positivity in mothers was 4.25%. However only in three cases the pair of mother and child were both positive for HBsAg. The mean anti HBs positivity in children was 23.75%. There was no statistically significant difference in the anti HBs positivity in different age groups of children. The observation that there is no statistically significant difference in the prevalence of HBV infection (HBsAg and HBs) amongst different age groups of children below five years signifies that a large proportion of HBV infection in children of this age is acquired via vertical transmission. It is also indicated that this mode of disease transmission is responsible for the majority of chronic carriers. Universal immunization of all infants is desirable to decrease the carrier pool and it is inferred from the present study that Hepatitis B immunization should begin at birth to have greater impact.     

Perinatal and intrafamily transmission of hepatitis B virus in three generations of a low-prevalence population

Family members of 47 hepatitis B virus (HBV)-carrier pregnant women were tested for the presence of hepatitis B surface antigen (HBsAg), other markers of HBV infection, and hepatitis A virus (HAV) antibodies. Eleven members of six families were found to be HBV DNA positive. Five of the anti-HBe-positive persons were found to be HBV DNA carriers, too. The mean age of the HBV DNA carriers was found to be lower than that of Hbe carriers; therefore, it is suggested that seroconversion to HBe occurs before the resolution of HBV DNA carrier state. Superinfection with hepatitis A virus was not found to influence the elimination of HBV-carrier state, as there was no correlation found between the hepatitis A exposure and the hepatitis B virus markers in the families. The low HBV prevalence in the population (0.3%) was in contrast to the high prevalence of the families of the HBV-carrier mothers (27.1%) and family members with HBV markers (50.4%). Significant positive correlation was found in the proportion of HBV-positive children, and the HBV history of their parents. When fathers were shown to be seronegative, the probability of HBV transmission was reduced by a factor of 6 (12.5% instead of 75%) probably due to reduced viral load and possibly by other factors. Several results indicate, that the noncytocidal hepatitis B virus clearing mechanism suggested by Guidotti et al. [1996, 1999] was effective also in the HBV-carrier human population.     

Protective efficacy, immunotherapeutic potential, and safety of hepatitis B vaccines

Hepatitis B vaccines are highly effective and safe and have been incorporated into national immunization programs in over 150 countries. The major humoral immune response is to the common a determinant of the surface antigen protein of the virus. Approximately 5-10% of healthy immunocompetent subjects do not mount an antibody response (anti-HBs). Non-response is associated with different HLA-DR alleles and impaired Th cell response, among other factors such as route of injection, age, gender, body mass, and other factors. Important hepatitis B surface antigen variants have also been identified, which may have a potential impact on immunization and routine screening of blood, blood products and tissues, and organs for transplantation. Strategies for hepatitis B immunization are reviewed. Over 1,000 million doses of hepatitis B vaccine have been used with an outstanding record of safety. There is no evidence of an association between hepatitis B vaccines and the sudden infant death syndrome, chronic fatigue syndrome, and multiple sclerosis (MS). Several studies are in progress on treatment of chronic hepatitis B infection by immunization with multiple antigenic components, combination of vaccine with antiviral drugs and cytokines, T cell vaccines, DNA vaccines alone or with DNA encoded immunomodulatory cytokines, and direct genetic manipulation of antigen presenting cells.     

Simultaneous quantitation and genotyping of hepatitis B virus by real-time PCR and melting curve analysis

Hepatitis B virus (HBV) genotype and HBV DNA levels have been implicated in clinical evaluation and prognosis of patients with chronic HBV infection. The aim of the present study was to develop a rapid and sensitive method for simultaneous HBV DNA quantitation and differentiation between HBV genotypes B and C in a single-step reaction by real-time PCR and melting curve analysis using SYBR Green I fluorescent dye. The genotypes obtained by this method were compared with those examined by PCR-RFLP and direct sequencing on 52 serum samples of patients with chronic HBV infection. Using the results obtained by direct sequencing and phylogenetic analysis as the reference, the accuracy of HBV genotyping by PCR-RFLP and melting curve analysis was 90.38 and 92.31%, respectively. The geometric mean of HBV DNA levels was 3.42×10⁶, 2.10×10⁶, 1.19×10⁵ and 3.10×10⁴ copies/μl in asymptomatic carriers, patients with chronic hepatitis, cirrhosis and hepatocellular carcinoma, respectively. It is concluded that this method has the advantages of rapidity, reproducibility and accuracy, which would be feasible and attractive for large-scale analysis, particularly in regions where HBV genotypes B and C are prevalent.     

Hepatitis B vaccine in infants from an endemic area: long-term anti-HBs persistence and revaccination

Persistence of anti-HBs in 156 Senegalese infants immunized with hepatitis B vaccine was studied for periods ranging from 2 to 6 years after booster dose administration. Six years after the booster dose, 90.4% of the infants had detectable anti-HBs antibodies, with 78.1% having titers higher than 10 mIU/ml. The geometric mean titer was 60 mIU/ml. Females showed higher anti-HBs values than males. In a group of 11 infants who received no booster dose, anti-HBs antibodies were detectable 7 years after the first dose. However, the geometric mean titer was lower (26 mIU/ml). Revaccination (56 infants) led to an increase of the geometric mean titer to 469 mIU/ml 2 months later. These results show that a booster injection every 5-6 years should provide adequate protective anti-HBs levels in infants.     

Long-term follow-up of hepatitis B carrier children treated with interferon and prednisolone

The long-term outcome of treatment with Interferon Alpha 2B with and without Prednisolone priming in children infected perinatally with hepatitis B was reviewed. The group studied included 48 children (aged 2-16 years), who were HBe antigen and hepatitis B DNA positive between 1991 and 1993. Twenty children were randomized to a therapeutic trial at that time, and received Prednisolone in reducing doses for 6 weeks and Interferon for 16 weeks while 22 children were monitored without treatment for 12 months. Fourteen of the untreated group and 6 additional children later received treatment with Interferon alone (n = 20). Eight children for whom treatment was declined were followed long term. Median follow-up was 7.5 years (range 1.5-10.6). There was no significant effect of Interferon therapy on seroconversion with or without Prednisolone at 12 months post-treatment compared to untreated children. On longer term follow-up, the 5-year HBeAg to anti-HBe seroconversion percentages, estimated from Kaplan-Meier curves, were 54% for Prednisolone plus Interferon, 22% for Interferon alone, and 12% for untreated children. The median time to seroconversion was 3.9 years (range 0.4-8.2) and was shortest in those treated with Prednisolone plus Interferon. Children who had elevated hepatic transaminase enzymes prior to treatment or during Prednisolone priming had a better response. In contrast to many European studies, no child cleared HBsAg and produced anti-HBs. Treatment with Prednisolone priming and Interferon, improved both the time and rate of seroconversion compared to no treatment or Interferon alone, suggesting that this combination of drugs might have an immunomodulatory effect.     

Standardized quantitative RT-PCR assays for quantitation of yellow fever and chimeric yellow fever-dengue vaccines

Yellow fever-dengue chimeras (CYDs) are being developed currently as live tetravalent dengue vaccine candidates. Specific quantitative assays are needed to evaluate the viral load of each serotype in vaccine batches and biological samples. A quantitative real-time RT-PCR (qRT-PCR) system was developed comprising five one-step qRT-PCRs targeting the E/NS1 junction of each chimera, or the NS5 gene in the yellow fever backbone. Each assay was standardized using in vitro transcribed RNA qualified according to its size and purity, and precisely quantified. A non RNA-extracted virus sample was introduced as external quality control (EQC), as well as 2 extraction controls consisting of 2 doses, 40 and 4,000 GEQ (genomic equivalents), of this EQC extracted in parallel to the samples. Between 6 and 10 GEQ/reaction were reproducibly measured with all assays and similar titers were obtained with the two methods when chimeric virus samples were quantified with the E/NS1- or the NS5-specific assays. Reproducibility of RNA extraction was ensured by automation of the process (yield>or=50%), and infectious virus was isolated in >or=80% of PCR-positive sera from immune monkeys.     

Linearized hepatitis B surface antigen and hepatitis B core-related antigen in the natural history of chronic hepatitis B

Changes in two novel HBV serological markers, linearized hepatitis B surface antigen (HQ-HBsAg) and hepatitis B core-related antigen (HBcrAg), in the natural history of chronic hepatitis B (CHB) have not been well characterized. Serum HQ-HBsAg and HBcrAg levels of 404 Asian treatment-naïve CHB patients were analysed in a cross-sectional manner. Patients were categorized into five groups: immune tolerant (IT group, n = 52), immune clearance (IC group, n = 105), hepatitis B e antigen (HBeAg)-negative hepatitis (ENH group, n = 97), HBeAg-negative quiescent group (ENQ group, n = 95) and CHB with hepatitis B surface antigen (HBsAg) seroclearance (SC group, n = 55). HQ-HBsAg and HBcrAg were measured and correlated with HBV DNA, HBsAg, HBV genotype and clinical parameters. HQ-HBsAg showed good correlation with HBsAg, especially in the ENQ group (r = 0.874, p <0.001). Correlation of HQ-HBsAg with HBV DNA was less prominent and weakest in the ENH group (r = 0.268, p 0.008). HBcrAg correlated best with HBV DNA in the ENQ group (r = 0.537, p <0.001). In the ENQ group, 42.1% of patients had undetectable HBcrAg; this subgroup of patients, when compared with those with detectable HBcrAg, had significantly lower median HBV DNA (3.17/4.48 log IU/mL, p <0.001) and HBsAg (5.05/5.96 log mIU/mL, p <0.001) levels. Forty per cent of the SC group patients had detectable HQ-HBsAg and/or HBcrAg up to 42 months after HBsAg seroclearance. When comparing anti-HBs positivity and median time after HBsAg seroclearance in the SC group with and without detectable HQ-HBsAg/HBcrAg, there was no significant difference (22.7% and 36.4%, respectively, p 0.284, and 76.5 and 93.2 months, respectively, p 0.245). HQ-HBsAg and HBcrAg showed unique patterns of distribution throughout the five disease phases of CHB, including high detectability rates after HBsAg seroclearance, opening up different possibilities for their applicability.     

Detection of hepatitis B viral DNA by polymerase chain reaction in patients with hepatitis B surface antigen

Hepatitis B virus (HBV) DNA was assayed using the polymerase chain reaction in serum samples of 116 hepatitis B surface antigen (HBsAg) carriers, including 30 positive for hepatitis B e antigen (HBeAg) and 86 negative for HBeAg. In the HBeAg-positive group, all were positive for HBV DNA. In the HBeAg-negative group, 80.2% were positive for HBV DNA (80.0% in the healthy carrier group, 90.0% in the chronic active liver disease group, and 69.2% in patients with cirrhosis). This study indicated that every HBeAg-positive carrier as well as the majority of HBeAg-negative carriers were infectious and, in the latter group, that viral replication is most active in patients with chronic active liver disease.     

乙型肝炎分子流行病学研究进展

乙肝的分子流行病学是运用先进的分子生物学技术研究乙肝流行病学的诸多问题,能够进一步从分子水平阐明乙型肝炎病毒感染的病因、致病过程及发病机制,对于疾病早期诊断、传染性的评估、病情的预测、抗病毒药物疗效的观察、疾病发展进程的监测和乙肝感染自然史的研究等方面均有重要的指导意义.针对近几年乙肝分子流行病学研究的几个热点即乙型肝炎病毒的检测、基因分型、基因系统进化分析、基因变异、基因多态性的研究进展作一回顾.虽然近年来该领域的研究迅速增多,但多数仍处于探索阶段,乙肝病毒感染、清除等诸多机制的研究仍任重而道远.     

Detection of hepatitis B virus DNA in serum and relation with the IgM class anti-HBc titers in hepatitis B virus infection

Sera from four groups of patients wtih different serologic markers of HBV infection were examined for HBV DNA using molecular hybridization technique and for IgM class anti-HBc using an ELISA based on the antibody capture principle. Results of HBV DNA assay were generally in good agreement with the presence of HBeAg. However, HBV DNA was found in 13% of anti-HBe+ sera and in one patient with anti-HBc as a sole marker. IgM anti-HBc was detected at high titers in acute hepatitis B patients and was also present during the "window-period." This marker was also found, though less frequently when other markers for HBV infectivity were absent, in chronic hepatitis B patients and healthy carriers. From these findings we conclude that the HBV DNA assay provides a reliable method of detecting the infectious agent, particularly in anti-HBe+ sera and sera with anti-HBc as a sole marker. The assay for IgM anti-HBc is useful for establishing the diagnosis of recent infection in patient with anti-HBc as a sole marker, and during acute hepatitis with very high aminotransferase values, a condition in which HBV DNA may be undetectable.     

2007年广州部分大学生乙肝疫苗接种与乙肝相关知识态度调查

目的了解大学生乙肝疫苗（HBV）接种情况和大学生对乙型肝炎的认知程度，为制定更好的免疫接种计划提供更为可靠的依据。方法2007年，在广州市抽取4所高等学校的部分大学生进行调查。结果调查191人，HBV接种率为76．44％，其中全程接种的为64．92％。HBV接种率及全程接种率，不同年龄学生间有显著性差异（P〈0．05），不同家庭经济收入的学生有差异（P〈0．05）。有乙肝疫苗接种史者、全程接种者对乙肝是否经日常生活接触传播的知晓率仅为56．16％、60．48％．经唾液传播的知晓率仅为41．78％、45．16％；97．4％的被调查者表示会劝亲人或朋友去接种乙肝疫苗，93．7％的被调查者表示会愿意接受乙肝病人或乙肝携带者赠送的礼物。20．9％的被调查者表示会回避与乙肝病人或乙肝携带者交往，同时86．9％的被调查者也表示不介意与乙肝携带者一起工作或学习。结论广州市大学生HBV接种率较商，对乙肝知识的知晓率较高，对乙肝病人多有正确的态度，但在某些方面存在误区？     

Field evaluation of the efficacy and immunogenicity of recombinant hepatitis B vaccine without HBIG in newborn Vietnamese infants

A study involving more than 2,000 infants was conducted in Vietnam to assess the field effectiveness and immunogenicity of recombinant hepatitis B vaccine given at birth, 1 month, 2 months, without concomitant hepatitis B immune globulin (HBIG). All received a 5 microg dose of H-B-VAX II at birth. Infants born to non-carrier mothers (Group 1; N = 1798) then received 2.5 microg doses at 1 and 2 months of age, while infants of HBeAg-negative (Group 2; N = 125) or HBeAg-positive (Group 3; N = 88) carrier mothers received 5 microg doses. No Group 1 or 2 vaccinees were infected. In Group 3, 12 (14.6%) of 82 infants did become infected (estimated efficacy 84%). 98.0-98.6% of uninfected infants who were tested for anti-HBs developed a seroprotective concentration > or = 10 IU/L. In hyperendemic Vietnam, where routine maternal screening and passive-active prophylaxis of high-risk infants with vaccine plus HBIG is not feasible, administration of vaccine alone to all newborns may control effectively HBV infection.     

Simultaneous administration of diphtheria-tetanus-pertussis-polio and hepatitis B vaccines in a simplified immunization program: immune response to diphtheria toxoid, tetanus toxoid, pertussis, and hepatitis B surface antigen.

We studied the interactions of hepatitis B vaccine with other vaccines used in the World Health Organization expanded programs of immunization. Three groups of Senegalese children were vaccinated with hepatitis B vaccine (HB) alone, diphtheria-tetanus-pertussis (DTP)-polio vaccine alone, or a combination of hepatitis B vaccine and DTP-polio vaccines simultaneously. The immune responses to HBsAg, tetanus toxoid, diphtheria toxoid, and pertussis were measured after one and two vaccinations at 6-month intervals. The immune responses to the combination of HB vaccine and DTP-polio vaccines were similar to the immune responses observed after administration of each vaccine alone. In addition, no adverse reactions were noted. These experimental trials also demonstrated that with a DTP-polio vaccine containing 30Lf of tetanus and diphtheria toxoids, two doses given at 6-month intervals are sufficient to provide a satisfactory immune response. In the case of pertussis and HB vaccines; however, a third dose is necessary.     

Complete genomic sequence and phylogenetic relatedness of hepatitis B virus isolates in Cambodia

Although it is known that Cambodia is one of the high endemic area of hepatitis B virus (HBV) infection, molecular characterization of HBV circulating in this country has not been reported. In this study, pre-S gene of HBV from 12 Cambodian patients was sequenced. Phylogenetic analysis based on the pre-S gene sequence revealed that 8 out of 12 isolates (66.7%) belonged to HBV/C1 and remaining four (33.3%) were HBV/B4. Furthermore, complete genomic sequences were also determined for three Cambodian HBV isolates. They all comprised of 3,215 bp long and two of them belonged to subgenotype B4, which had recombination event with genotype C in the precore/core gene confirmed by SimPlot and BootScanning analyses. Our results showed that both HBV strains belonged to subgenotypes B4 and C1, which are circulating in this country. This is the first report on molecular characterization of the HBV prevalent in Cambodia.     

Low-cost hepatitis B vaccine improves uptake among self-paying health-care students.

Advisory committees recommend hepatitis B (HBV) immunization for professional and student health-care workers. However, the currently licensed vaccines are expensive, and previous surveys have shown that few students (14%) have been immunized in Canada. A low-cost immunization program was offered to health-care students in order to determine whether the effectiveness of HBV immunization could be improved by substantially reducing the vaccine cost to recipients. The immunogenicity, side effects, and 3-dose completion rate of a low-cost Korean HBV vaccine were compared with a similar U.S.-made vaccine. A total of 922 postsecondary students enrolled in 6 health-care disciplines in Ottawa, Canada were surveyed for hepatitis-B immunization status. Nonimmunized students were subsequently offered HBV vaccine at total cost of $15 (Canadian), randomly allocated to receive 3 intramuscular doses of either Korean or U.S.-made plasma-derived HBV vaccine in a double-blind fashion, surveyed about side effects, and tested for hepatitis B surface antibody seroconversion. Only 12% of the 922 surveyed students had been previously immunized when vaccine was obtainable only at high cost. However, 66% of those not immunized participated in the vaccine trial and paid the $15 fee. Hepatitis-B surface antibody seroconversion (greater than or equal to 10 sample ratio units by radioimmunoassay) occurred in 291/311 (93.6%) and 299/310 (96.5%) of recipients of 3 doses of the Korean and U.S. vaccines, respectively (P = 0.10). There were no meaningful differences in vaccine adverse effects, and 92.6% of recipients of either vaccine completed 3 doses.(ABSTRACT TRUNCATED AT 250 WORDS)     

Human antibody response to immunization with 17D yellow fever and inactivated TBE vaccine

The antibody response against flaviviruses tick-borne encephalitis (TBE), Kyasanur Forest disease (KFD), Murray Valley encephalitis (MVE), West Nile fever (WNF), Japanese B encephalitis (JE), dengue 2 (DEN-2), and yellow fever (YF) was studied in humans after administration of an inactivated TBE virus vaccine. Individuals were either prevaccinated with 17D yellow fever (experimental group) or without any previous exposure to flaviviruses (control group). The appearance of serum titres of homologous and heterologous haemagglutination inhibition (HI) antibodies, heterotypic DEN-2 neutralizing antibodies, and TBE enzyme-linked immunosorbent assay (ELISA) antibodies were examined. Individuals prevaccinated with the 17D yellow fever developed an antibody pattern that contrasted with that of the control group. This pattern was characterized as follows: (1) Predominantly anti-TBE IgG antibodies appeared earlier and in higher titres than in the control group, (2) heterologous HI antibodies cross-reacting with the WN flavivirus subgroup preceded the appearance of homologous HI antibodies, (3) a broad spectrum HI response was observed against all flaviviruses tested, and (4) low titre heterotypic DEN-2 neutralizing antibodies were formed in about half of the cases. These observations are discussed in the context of cross-reactivity, cross-protection and virus infection enhancement.     

Characteristics of core promoter and precore stop codon mutants of hepatitis B virus in Vietnam

In Asia, genotypes B and C are the most common genotypes of hepatitis B virus (HBV); and genotype C causes more severe liver disease. Core promoter/precore (CP/PC) mutants, known to be linked to these genotypes, could have an impact on the progression and severity of liver disease. Sera of 115 patients, including 39 acute and 76 chronic Vietnamese HBV infected patients, were tested for their liver profile, HBeAg, HBV genotypes, and HBV DNA level. Fragments of 282 nucleotides covering CP/PC were amplified, sequenced, and analysed. In the acute group, CP/PC mutants accounted for 38.4 and 25.6%, respectively. Genotype B was found to be predominant (74.3%, P < 0.05) and linked to the PC mutant (A1896) (P < 0.05). In the chronic group, CP/PC mutants accounted for 61.7 and 32.8%. CP mutants, especially the T1762/A1764 double mutant, were found to correlate with genotype C (81%, P < 0.001), liver cirrhosis, and hepatocellular carcinoma (P < 0.05). Therefore, genotype C in Vietnam, which carried high rate of C-1858 (70%), could play an important role in causing severe chronic liver disease.