Hepatitis B vaccination: The key towards elimination and eradication of hepatitis B

Fighting against viral hepatitis: lessons from Taiwan

Viral hepatitis and its sequelae are important health problems worldwide, including Taiwan. For the last 40 years, Taiwan's scientists and health care providers have worked hard to control these sequelae, and the results have been excellent. The author, Ding-Shinn Chen, had a key role in planning and establishing the control program in Taiwan, and participated in the endeavors from the very beginning. In this perspective, he describes how he became interested in research as a medical student, his encounters with hepatitis B and C, how he and his colleagues started early detection of hepatocellular carcinoma (HCC), how he helped Taiwan's government create and implement the Viral Hepatitis Control Program, and how the effectiveness of the program in the decrease of hepatitis B carriage and HCC was monitored. He also discusses how he pioneered the use of interferon-α plus ribavirin to treat chronic hepatitis C. Hepatitis B viral load as a risk factor for HCC and cirrhosis in hepatitis B surface antigen carriers is reviewed briefly, as is the prevention of sequelae by antiviral therapies. Finally, Dr. Chen discusses unresolved issues that must be addressed and predicts the changes of the patterns of liver disease in Taiwan beyond the mid-21st century, which is in part affected by the fight against viral hepatitis that was initiated in the early 1980s.

CONCLUSION

Dr. Chen's perspective illustrates Taiwan's fight against viral hepatitis over the last 40 years. This experience can be shared by other countries in which the disease is equally prevalent.

Therapeutic vaccines and immune-based therapies for the treatment of chronic hepatitis B: perspectives and challenges

The treatment of chronic hepatitis B virus (HBV) infection has greatly improved over the last 10 years, but alternative treatments are still needed. Therapeutic vaccination is a promising new strategy for controlling chronic infection. However, this approach has not been as successful as initially anticipated for chronic hepatitis B. General impairment of the immune responses generated during persistent HBV infection, with exhausted T cells not responding correctly to therapeutic vaccination, is probably responsible for the poor clinical responses observed to date. Intensive research efforts are now focusing on increasing the efficacy of therapeutic vaccination without causing liver disease. Here we describe new approaches to use with therapeutic vaccination, in order to overcome the inhibitory mechanisms impairing immune responses. We also describe innovative strategies for generating functional immune responses and inducing sustained control of this persistent infection.

Thiazolides as novel antiviral agents. 1. Inhibition of hepatitis B virus replication

We report the syntheses and activities of a wide range of thiazolides [viz., 2-hydroxyaroyl-N-(thiazol-2-yl)amides] against hepatitis B virus replication, with QSAR analysis of our results. The prototypical thiazolide, nitazoxanide [2-hydroxybenzoyl-N-(5-nitrothiazol-2-yl)amide, NTZ] 1 is a broad spectrum antiinfective agent effective against anaerobic bacteria, viruses, and parasites. By contrast, 2-hydroxybenzoyl-N-(5-chlorothiazol-2-yl)amide 3 is a novel, potent, and selective inhibitor of hepatitis B replication (EC(50) = 0.33 μm) but is inactive against anaerobes. Several 4'- and 5'-substituted thiazolides show good activity against HBV; by contrast, some related salicyloylanilides show a narrower spectrum of activity. The ADME properties of 3 are similar to 1; viz., the O-acetate is an effective prodrug, and the O-aryl glucuronide is a major metabolite. The QSAR study shows a good correlation of observed EC(90) for intracellular virions with thiazolide structural parameters. Finally we discuss the mechanism of action of thiazolides in relation to the present results.

Hepatitis B virus infection from an evolutionary point of view: how viral, host, and environmental factors shape genotypes and subgenotypes

Hepatitis B virus (HBV) has an overwhelming distribution in the world and causes important human health problems. It has infected one-third of the global population and more than 350 million people are chronic carriers. Several aspects of HBV infection confer adaptive advantages that lead to a highly efficient dissemination of the virus through different routes of transmission. HBV genotypes and subgenotypes have been associated with differences in clinical and virological characteristics, indicating that they may play a role in the virus-host relationship. In particular, a clear association between genotype A and chronic outcomes in both children and adults depending on the subgenotype involved, and between genotype C and a higher risk of complications from HBV infection, has been demonstrated. Interestingly, subgenotype A2 and genotype C are respectively likely to predominate in high-risk groups for sexual transmission and in areas where perinatal transmission is the major mode of HBV dissemination. An evolutionary approach to HBV infection, based on the principles of natural selection, may offer explanations for how modes of transmission may favor some genotypes and subgenotypes over others and, ultimately, influence HBV virulence.

Review article: prevention and management of hepatitis B and C infection in patients with inflammatory bowel disease

BACKGROUND

Viral hepatitis is a very common infection.

AIM

To review the prevention and management of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection in inflammatory bowel disease (IBD).

METHODS

Bibliographical searches were performed in MEDLINE up to September 2010.

RESULTS

The prevalence of both HBV and HCV infection in IBD patients is now similar to that of the general population. All IBD patients should be screened for HBV markers at diagnosis. Liver dysfunction in IBD patients treated with immunosuppressants is more frequent and severe in HBV than in HCV carriers and is associated with combined immunosuppression. Inpatients receiving anti-TNF drugs, HBV reactivation is common unless anti-viral prophylaxis is administered. HBsAg-positive patients should receive anti-viral prophylaxis before starting immunosuppressants. As interferon might worsen underlying IBD, nucleoside ⁄ nucleotide analogues are preferred for anti-viral prophylaxis in patients with HBV (tenofovir ⁄ entecavir are preferred to lamivudine). IBD patients should be vaccinated against HBV at diagnosis. The response rate to HBV vaccination is low, mainly in those receiving anti-TNF therapy. The serological response to HBV vaccine should be confirmed, and patients with an inadequate response should receive a second full series of vaccine. Peginterferon (ribavirin) for HCV infection is as effective and safe as in non-IBD patients.

CONCLUSIONS

The present manuscript poses a series of questions on the prevention and management of HBV/HCV infection in IBD, and attempts to answer them using scientific evidence in order to provide practical conclusions for the clinician.

Quantification of HBsAg: Basic virology for clinical practice

Hepatitis B surface antigen (HBsAg) is produced and secreted through a complex mechanism that is still not fully understood. In clinical fields, HBsAg has long served as a qualitative diagnostic marker for hepatitis B virus infection. Notably, advances have been made in the development of quantitative HBsAg assays, which have allowed viral replication monitoring, and there is an opportunity to make maximal use of quantitative HBsAg to elucidate its role in clinical fields. Yet, it needs to be underscored that a further understanding of HBsAg, not only from clinical point of view but also from a virologic point of view, would enable us to deepen our insights, so that we could more widely expand and apply its utility. It is also important to be familiar with HBsAg variants and their clinical consequences in terms of immune escape mutants, issues resulting from overlap with corresponding mutation in the P gene, and detection problems for the HBsAg variants. In this article, we review current concepts and issues on the quantification of HBsAg titers with respect to their biologic nature, method principles, and clinically relevant topics.

Hepatitis B virus infection, its sequelae, and prevention by vaccination

Hepatitis B virus (HBV) infection is a global health problem. There are >350 million of people chronically infected with this virus worldwide. Hepatitis B vaccines are effective in preventing the infection. Humoral immunity is the key factor in conferring the protection. Hepatitis B surface antibody titers of ≥10mIU/mL are protective. Chronic carriage of HBV is related to the age when the infection occurs, the younger the age the higher the chronicity rate. Hence, vaccination should be given in early childhood. People vaccinated in infancy have a protection of >20 years, and hepatocellular carcinoma decreases in them. Although the vaccine-conferred immunity wanes by time, a universal booster is not recommended at present.

Management of hepatitis B: Consensus of the Japan Society of Hepatology 2009

Recently, much progress has been made in the field of hepatitis B, such as natural history of the disease in relation to the amount of hepatitis B virus (HBV) DNA, genotypes of HBV influencing the natural course and treatment effects, mutations of HBV influencing the severity of the disease and development of hepatocellular carcinoma, and antiviral treatment such as nucleos(t)ide analogues and pegylated interferon. To make the consensus for the diagnosis, management and treatment of hepatitis B, a meeting was held during 45th annual meeting of Japan Society of Hepatology (JSH) in June 2009. In the meeting, recommendations and informative statements were discussed on the following subjects: (i) natural history of HBV infection; (ii) clinical implication of HBV genotypes; (iii) HBV mutations and their potential impact on pathogenesis of HBV infection; (iv) indications for antiviral treatment of chronic hepatitis B; (v) nucleos(t)ide analogues for chronic hepatitis B; and (vi) interferon therapy for chronic hepatitis B. The presenters reviewed the data on these subjects and proposed the consensus statements and recommendations. These statements were discussed among the organizers and presenters, and were approved by the participants of the meeting. In the current report, the relevant data were reviewed and the 12 consensus statements and nine recommendations on chronic hepatitis B were described.

Can engineered "designer" T cells outsmart chronic hepatitis B?

More than 350 million people worldwide are persistently infected with human heptatitis B virus (HBV) and at risk to develop liver cirrhosis and hepatocellular carcinoma making long-term treatment necessary. While a vaccine is available and new antiviral drugs are being developed, elimination of persistently infected cells is still a major issue. Recent efforts in adoptive cell therapy are experimentally exploring immunotherapeutic elimination of HBV-infected cells by means of a biological attack with genetically engineered "designer" T cells.

Retrospective characterization of the S open reading frame of HBV isolated from children with membranous nephropathy treated with interferon-alpha2b

BACKGROUND

A causal relationship exists between HBV infection and membranous nephropathy. The association is especially close in Black children in sub-Saharan Africa. Interferon-alpha2b is commonly used to treat this condition, but is effective in only 30-40% of patients. The reason for the poor response is unknown. The objective of this study was to determine if mutations in the surface gene of HBV isolated from Black children with HBV-associated membranous nephropathy before, during and after interferon treatment, have any effect on treatment response and vice versa.

METHODS

HBV DNA was extracted from a responder, a reverter and a non-responder before and after initiation of 16 weeks of interferon-alpha2b treatment. The preS1/preS2/S region was amplified, cloned and sequenced.

RESULTS

The preS2 region was the most variable in the reverter and the non-responder, and the S region was the most variable in the non-responder. Phylogenetic analysis showed that the viral population dynamics between the responder and the reverter/non-responder strains differed as a result of mutations in the surface gene.

CONCLUSIONS

The presence of mutations in the S region of HBV could be used as predictive markers to differentiate interferon-alpha2b responders from non-responders provided that detailed analysis of further genomes confirms our findings.

Hepatitis B vaccination in children: the Taiwan experience

The world's first nationwide hepatitis B virus (HBV) universal vaccination program for infants was launched in Taiwan in July, 1984. All infants received three to four doses plasma or recombinant HBV vaccines. In addition, infants of HBeAg-positive mothers received 0.5ml of hepatitis B immunoglobulin within 24hours after birth. The vaccination coverage rate is as high as 97%. Seroprevalence of hepatitis B surface antigen (HBsAg) declined from 9.8% (prevaccination period) to 0.6% in children in Taipei City after 20years of mass vaccination. The seropositive rates for HBsAg, antibody to HBsAg, and antibody to hepatitis B core antigen were 1.2%, 50.5%, and 3.7%, respectively, in those born after the vaccination program (<20years old) in 2004. In line with the decrease of chronic HBV infection, the incidence of hepatocellular carcinoma (HCC) also decreased in children in Taiwan. From 1981 to 1994, the incidence of HCC in 6- to 9-year-olds declined from 0.52/100,000 for those born between 1974 and 1984 to 0.13 for those born between 1984 and 1986 (p<0.001). We extended the observation to 2000, the incidence of HCC per 100,000 children declined from 0.54 to 0.20. The prevalence of a determinant mutants (amino acids 121-149 of HBsAg) in Taiwanese carrier children was 7.8% (eight out of 103) in 1984, increased to 19.6% (10 out of 51) in 1989, peaked at 28.1% (nince out of 32) in 1994, and remained stationary at 23.1% (three out of 13) and about 25% in 1999 and 2004, respectively; it was higher in those fully vaccinated compared with those not vaccinated. The other group of subjects who are susceptible to vaccine failure is the immunocompromized hosts. We observed some de novo HBV infection in children after liver transplantation. Despite of the success of hepatitis B immunization, childhood chronic HBV infection and HCC were not eliminated by the universal vaccination program. Among those HBsAg carriers born after the vaccination program, 89% of their mothers were found to be positive for HBsAg, indicating the importance of maternal transmission. This was also true in the mothers of children with HCC, of them 96% were HBsAg positive. After two decades of universal infant HBV vaccination, we found this program provides long-term protection for up to more than 20years, and a universal booster is not required for the primary HBV vaccinees before adulthood. Mother-to-child transmission, although largely diminished, is still the main cause for immunoprophylaxis failure. The emergence of escape mutant did not impose increased risk of chronic infection at present. Nevertheless, development of new vaccines may overcome the vaccine failure.

Toward elimination and eradication of hepatitis B

Hepatitis B virus (HBV) causes important human health problems. It has infected one-third of the world's population and approximately 360 million people are chronic carriers. Worldwide, 0.5-1.2 million deaths are attributed to HBV infection annually. Therefore, global control of HBV infection is important. HBV infection can be intervened by interrupting routes of transmission, treating the chronically infected, and preventing the susceptibles with immunoprophylaxis. All these measures are effective. Nevertheless, although pegylated interferons or nucleos(t)ide analogs are effective for the treatment of chronic hepatitis B, chronic carriage of HBV is not easy to eliminate, as revealed by the frequent persistence of hepatitis B surface antigen, despite satisfactory responses to these treatments. On the other hand, hepatitis B vaccination has been shown to preclude HBV infection effectively. This is particularly true for pre-exposure prophylaxis. Worthy of note is the universal vaccination of newborn infants. This is the most effective means of preventing HBV infection, especially for those born to HBV carrier mothers. To eliminate and eradicate hepatitis B, first, HBV in the chronically infected should be eradicated or strongly and efficiently suppressed, so that the infection does not spread rampantly. Second, all the transmission routes should be interrupted. Lastly, but most effectively, is to immunize all susceptibles. The difficulties and possible solutions of each approach are discussed. In conclusion, the existing means to prevent and treat HBV infection render our goal toward eliminating and eradicating hepatitis B possible, although it will take much time and effort to achieve this objective.

Poly[di(carboxylatophenoxy)phosphazene] is a potent adjuvant for intradermal immunization

Intradermal immunization using microfabricated needles represents a potentially powerful technology, which can enhance immune responses and provide antigen sparing. Solid vaccine formulations, which can be coated onto microneedle patches suitable for simple administration, can also potentially offer improved shelf-life. However the approach is not fully compatible with many vaccine adjuvants including alum, the most common adjuvant used in the vaccine market globally. Here, we introduce a polyphosphazene immuno adjuvant as a biologically potent and synergistic constituent of microneedle-based intradermal immunization technology. Poly[di(carboxylatophenoxy)phosphazene], PCPP, functions both as a vaccine adjuvant and as a key microfabrication material. When used as part of an intradermal delivery system for hepatitis B surface antigen, PCPP demonstrates superior activity in pigs compared to intramascular administration and significant antigen sparing potential. It also accelerates the microneedle fabrication process and reduces its dependence on the use of surfactants. In this way, PCPP-coated microneedles may enable effective intradermal vaccination from an adjuvanted patch delivery system.

Optic neuritis following hepatitis B vaccination in a 9-year-old girl

Hepatitis B vaccination can prevent hepatitis B virus infection and its serious consequences, including liver cancer and cirrhosis. Serious side effects reported after receiving hepatitis B vaccination are very uncommon. A majority of the ophthalmological complications seen following hepatitis B vaccination consist of vision loss, optic neuritis, papillary edema, uveitis, acute placoid pigment epitheliopathy and central vein occlusion. We present a 9-year-old girl who was referred to our hospital with decrease in vision and pain in the left eye a week after hepatitis B vaccination. A diagnosis of vaccine-induced optic neuritis was made. The clinical picture improved after systemic corticosteroid treatment. Acute optic neuritis might be a rare complication of hepatitis B vaccination. Parents should be aware of the potential serious side effects of the vaccine.