Unsolved problems and future perspectives of hepatitis B virus vaccination

Vaccines and Vaccine Response in the Small Bowel Transplant Patient

Vaccines should be regularly administered and their efficiency controlled, before and after intestinal transplantation. The household and health care providers should also be immunized, to further prevent transmission. Universal vaccination providing " herd immunity" should be enforced. Recommendations are given about timing, indications, and contraindications of each individual vaccine, before and after transplantation.

Overview of Hepatitis B Vaccine Non-Response and Associated B Cell Amnesia: A Scoping Review

BACKGROUND

The advent of the hepatitis B vaccine has achieved tremendous success in eradicating and reducing the burden of hepatitis B infection, which is the main culprit for hepatocellular carcinoma-one of the most fatal malignancies globally. Response to the vaccine is achieved in about 90-95% of healthy individuals and up to only 50% in immunocompromised patients. This review aimed to provide an overview of hepatitis B vaccine non-response, the mechanisms involved, B cell amnesia, and strategies to overcome it.

METHODS

Databases, including Google Scholar, PubMed, Scopus, Cochrane, and ClinicalTrials.org, were used to search and retrieve articles using keywords on hepatitis B vaccine non-response and B cell amnesia. The PRISMA guideline was followed in identifying studies, screening, selection, and reporting of findings.

RESULTS

A total of 133 studies on hepatitis B vaccine non-response, mechanisms, and prevention/management strategies were included in the review after screening and final selection. Factors responsible for hepatitis B vaccine non-response were found to include genetic, immunological factors, and B cell amnesia in healthy individuals. The genetic factors were sex, HLA haplotypes, and genetic polymorphisms in immune response markers (cytokines). Non-response was common in conditions of immunodeficiency, such as renal failure, haemodialysis, celiac disease, inflammatory bowel disease, hepatitis C co-infection, and latent hepatitis B infection. Others included diabetes mellitus and HIV infection. The mechanisms involved were impaired immune response by suppression of response (T helper cells) or induced suppression of response (through regulatory B and T cells).

DISCUSSION

A comprehensive and careful understanding of the patient factors and the nature of the vaccine contributes to developing effective preventive measures. These include revaccination or booster dose, vaccine administration through the intradermal route, and the use of adjuvants in the vaccine.

How does diabetes type 1 affects immune response to hepatitis B virus vaccine in pediatric population? Evaluation of a booster dose in unresponsive subjects with type 1 diabetes

BACKGROUND

Hepatitis B virus (HBV) vaccine reduced the incidence of Hepatitis B worldwide. Genetic variability, by the presence of specific haplotypes of HLA system (HLA-DR3, HLA-DR4), influences the response to the vaccination. Subjects affected by type 1 diabetes (T1D), contrary to non-diabetics, have a high prevalence of Hepatitis B.

METHODS

The objective of the study was to evaluate anti-HBs antigen (anti-HBsAg) antibody (Ab) in a group of 201 children (age range: 2-18 years), regularly vaccinated against HBV according to the national vaccination schedule. Patients with anti-HBs Ab≥10 mIU/mL have been defined "responders" and those with anti-HBs Ab<10mIU/mL have been defined "non-responders." The possible association between the T1D and a low immune response to the vaccine has been subsequently valued. Besides the presence of T1D, other possible influential variables have been studied: sex, age, presence of celiac disease and Hashimoto's thyroiditis, intervening years from the diagnosis of diabetes and presence/absence of diabetic ketoacidosis at time of diagnosis.

RESULTS

Among the 201 subjects with T1D, 90 (44.8%) were responders, while 111 (55.2%) were non-responders; among the 145 subjects without T1D, 86 (59.3%) were responders and 59 (40.7%) non-responders. We invited "Subjects with T1D non-responders" to undergo a booster dose of the same vaccine. Of these, 21 refused the booster, reducing the sample to 90 patients. After 4 weeks from the booster dose 81 patients showed seroconversion ("false non-responders"), and 9 did not ("true non-responders").

CONCLUSIONS

After the booster dose, immune response in our cross-section has been similar to general population. Given the high frequency of "false non-responders" anti-HBsAg Ab should be tested in T1D patients and a booster dose should be administrated in non-responders.

Hybrid large hepatitis B surface protein composed of two viral genotypes C and D induces strongly cross-neutralizing antibodies

Hepatitis B virus (HBV) vaccination is known to effectively decrease the risk of HBV infection. However, several issues need to be addressed in order to develop an improved HBV vaccine. Although the HBV vaccine has been shown to be effective, this vaccine needs to be more efficacious in defined groups, including non-responders (i.e., individuals who do not develop a protective response even after vaccination) and in health care workers and travelers who require rapid protection. Furthermore, it has been reported that universal HBV vaccination has accelerated the appearance of vaccine-escape mutants resulting from the accumulation of mutations altering the "a" determinant of the hepatitis B surface (HBs) protein. To address these problems, we have been focusing on the large HBs (LHBs) protein, which consists of three domains: pre-S1, pre-S2, and S (in N- to C-terminal order). To enhance the immunogenicity of LHBs, we developed a yeast-derived hybrid LHBs (hy-LHBs) antigen composed of the LHBs proteins from two distinct genotypes (Genotypes C and D). The levels of antibodies induced by hy-LHBs immunization were high not only against S, but also against the pre-S1 and pre-S2 domains. Additionally, hy-LHBs immunization induced significantly more strongly cross-reactive neutralizing antibodies than did small HBs (SHBs) or LHBs of any genotype alone. These findings suggested that hy-LHBs might serve as a candidate antigen for use in an improved prophylactic HBV vaccine.

Intranasal HBsAg/HBcAg-Containing Vaccine Induces Neutralizing Anti-HBs Production in Hepatitis B Vaccine Non-Responders

Hepatitis B vaccine induces the production of antibodies against hepatitis B surface antigen (anti-HBs) and prevents hepatitis B virus (HBV) infection. However, 5-10% of individuals cannot develop anti-HBs even after multiple vaccinations (HB vaccine non-responders). We developed an intranasal vaccine containing both HBs antigen (HBsAg) and HB core antigen (HBcAg) and mixed it with a viscosity enhancer, carboxyl vinyl polymer (CVP-NASVAC). Here, we investigated the prophylactic capacity of CVP-NASVAC in HB vaccine non-responders. Thirty-four HB vaccine non-responders were administered three doses of intranasal CVP-NASVAC. The prophylactic capacity of CVP-NASVAC was assessed by evaluating the induction of anti-HBs and anti-HBc (IgA and IgG) production, HBV-neutralization activity of sera, and induction of HBs- and HBc-specific cytotoxic T lymphocytes (CTLs). After CVP-NASVAC administration, anti-HBs and anti-HBc production were induced in 31/34 and 27/34 patients, respectively. IgA anti-HBs and anti-HBc titers significantly increased after CVP-NASVAC vaccination. HBV-neutralizing activity in vitro was confirmed in the sera of 26/29 CVP-NASVAC-administered participants. HBs- and HBc-specific CTL counts substantially increased after the CVP-NASVAC administration. Mild adverse events were observed in 9/34 participants; no serious adverse events were reported. Thus, CVP-NASVAC could be a beneficial vaccine for HB vaccine non-responders.

Immune response induced by recombinant pres2/S-protein and a pres2-S-protein fused with a core 18-27 antigen fragment of hepatitis B virus compared to conventional HBV vaccine

Although comprehensive vaccination is the cornerstone of public health programs to control hepatitis B virus (HBV) infections, 5% of people who receive the existing vaccine do not develop proper immunity against HBV. To overcome this challenge, researchers have tried using various protein fragments encoded by the virus genome to achieve better immunization rates. An important antigenic component of HBsAg called the preS2/S or M protein has also received much attention in this area. The gene sequences of preS2/S and Core18-27 peptide were extracted from the GenBank (NCBI). Final gene synthesis was conducted with pET28. Groups of BALB/c mice were immunized with 10 μg/ml of recombinant proteins and 1 μg/ml CPG7909 adjuvant. Serum levels of IF-γ, TNF-α, IL-2, IL-4, and IL-10 were measured by ELISA assay method on spleen cell cultures on day 45, and IgG1, IgG2a, and total IgG titers obtained from mice serum were quantified on days 14 and 45. Statistical analysis did not show any significant difference between the groups regarding IF-γ level. There were, however, significant differences in terms of IL-2 and IL-4 levels between the groups receiving preS2/S-C18-27 with and without adjuvant and the groups receiving both preS2/S and preS2/S-C18-27 (Plus Recomb-Plus Recomb: the group of mice that received both preS2/S and preS2/S-C18-27 simultaneously). The strongest total antibody production was induced by immunization with both recombinant proteins without CPG adjuvant. The groups that received both preS2/S and preS2/S-C18-27, whether with or without adjuvant, were significantly different from those that received the conventional vaccine considering most abundant interleukins. This difference suggested that higher levels of efficacy can be achieved by the use of multiple virus antigen fragments rather than using a single fragment.

Immune Status for Hepatitis B and Risk for Occupational Exposure Virus Among Italian Nurses

Background: Healthcare workers (HCWs) are considered at higher risk for hepatitis B virus infection compared to the general population, due to their potential contact with blood or body fluids and possible needle stick injuries. In turn, infected HCWs may be a risk for patients. Hepatitis B vaccination programs represent a strategic approach to control the infection. Objectives: In this study, we aimed to evaluate the serological status of HCWs employed at the teaching hospital of Rome Tor Vergata and their risk of occupational injuries after the adoption of directive 2010/32/EU. Methods: Medical records of 539 HCWs were evaluated during their occupational medical examination at the Tor Vergata teaching hospital (PTV). All subjects were screened for specific viral markers: Hepatitis B surface antibodies (anti-HBs IgG), antibodies to hepatitis core antigen (anti-HBc IgG), and hepatitis B surface antigen (HBsAg). Data regarding needlestick injuries were collected by the prevention service team during the same year. Results: In this sample population, we found five subjects (0.9%) positive to the HBsAg, and most of them (four) were born in foreign countries. Moreover, seven subjects (1.3% of our population) were HBsAg-positive and anti-HBc-positive. A protective anti-HBs titer was found in 462 out of 527 (85.7%) subjects. The risk of being serologically unprotected was higher in males and subjects aged 40 years or older. The nurses were more protected than other healthcare professionals considering the anti-hepatitis B surface antibody titer. In 2018, 16 needlestick injuries were reported among our population of HCWs, with a global risk of 2.9% per year. Conclusions: Although hepatitis B virus (HBV) infection rate among HCWs was similar to that of the general population, the risk of HBV transmission in HCWs was likely to be high due to suboptimal vaccination coverage.

Undetectable Anti-HBs Antibodies: Need of a Booster Dose for HIV-1-Infected Individuals

HBV vaccination effectively prevents HBV transmission and the development of liver cancer. Disease progression and liver-related complications are more common in HIV-1/HBV co-infected than HBV mono-infected individuals. A considerable body of literature, which will be reviewed here, indicates that response to HBV vaccine is suboptimal in HIV-1-infected individuals and that the poor maintenance of protective immunity to HBV vaccines in these individuals is an important medical issue. Several factors affect HBV vaccine response during HIV-1 infection including CD4+ T cell counts, B cell response, vaccine formulation, schedules, and timing of antiretroviral therapy (ART). The initial response to HBV vaccination also plays a critical role in the sustainability of antibody responses in both HIV-1-infected and uninfected vaccinees. Thus, regular follow-up for antibody titer and a booster dose is warranted to prevent HBV transmission in HIV-1 infected people.

Long-term immune protection against HBV: associated factors and determinants

In Italy, vaccination against hepatitis B became compulsory for all the newborns and 12-years-old adolescents in 1991. The main purpose of this study was to evaluate the persistence of long-term protection against HBV in medical students of the University of L’Aquila and in postgraduates Medical Doctors (HCWs) working in San Salvatore Hospital. The second aim was to study the variables associated with a protective anti-HBs antibody level, such as age at vaccination, gender, time elapsed from the last dose of vaccination.

Three hundred and forty-two subjects were enrolled from January 2017 to January 2019 and a blood sample was collected to evaluate the levels of serum HBsAg, anti-HBs and anti-HBc. Statistical analysis calculated a multivariable logistic regression model to examine predictors of a protective anti-HBs titer. The larger part (239, 70%) of the students had an anti-HBs titer >10 mIU/mL, those were statistically significant older (26.7 vs 24.5 years, p < .001), vaccinated at age 12 years (83.5% vs 59.9% among vaccinate at infancy, p < .001) and more frequently attending postgraduate medical school (80.8% vs 57.5% among healthcare profession school, p < .001). The multivariable logistic regression model showed that HBV vaccination at age of 12 was significantly and independently associated with protective titers (OR = 10.27, p = .019).

The results agreed with literature on HBV vaccination, confirming the efficacy of vaccination after 20 years. In particular, our results suggest that adolescent administration is the main predictor of a protective title, regardless of gender, course and years since vaccinations.

Hepatitis B virus pre-S region: Clinical implications and applications

Hepatitis B virus (HBV) infection is a major threat to global public health, which can result in many acute and chronic liver diseases. HBV, a member of the family Hepadnaviridae, is a small enveloped DNA virus containing a circular genome of 3.2 kb. Located upstream of the S-open-reading frame of the HBV genome is the pre-S region, which is vital to the viral life cycle. The pre-S region has high variability and many mutations in the pre-S region are associated with several liver diseases, such as fulminant hepatitis (FH), liver cirrhosis (LC), and hepatocellular carcinoma (HCC). In addition, the pre-S region has been applied in the development of several pre-S-based materials and systems to prevent or treat HBV infection. In conclusion, the pre-S region plays an essential role in the occurrence, diagnosis, and treatment of HBV-related liver diseases, which may provide a novel perspective for the study of HBV infection and relevant diseases.

Vaccination against Hepatitis B: A Scoping Review

Objective:

Elimination of viral hepatitis by 2030 as one of the international Sustainable Development Goals puts the hepatitis B vaccination on the forefront. However, barriers to vaccination reported in various studies are of concern. This study explores the global barriers for effective uptake of Hepatitis-B vaccination.

Methods:

A scoping review of studies reporting hepatitis B vaccination barriers was done using PMC data base and Google scholar search engine. About 803 journal articles and reports on hepatitis B barriers were retrieved but only 36 most relevant items during last 10 years were identified, pile sorted, grouped and analyze.

Results:

Overall 74 barriers have been identified for effective uptake of hepatitis-B vaccines. Most studies focused on non-zero dose of hepatitis B vaccine, One-third of the barriers are related to system issues, one-fourth of the barriers were related to caregiver education or awareness, fear of side effect, migration etc., one-fifth barriers were related to service provider issues like poor out-reach, home visits, poor communication and/relation with the caregivers, failure to identify unimmunized children etc., and other barriers were social-cultural issues. The review reveals limited availability and accessibility to health-facility based immunization, lack of awareness among caregivers, poor communication by the healthcare workers and negative relationships with the beneficiaries, cost of vaccine in private sector, inconvenience time and place of vaccination etc. as the major barriers for hepatitis B vaccination. Barriers varied from country to country.

Conclusion:

Myriad barriers for reduced hepatitis-B vaccine uptake need to be addressed contextually as countries are at different stages of hepatitis-B vaccination implementation.

Successful response of intradermal hepatitis B vaccine in nonresponders of intramuscular hepatitis B vaccine in general and hemodialysis population

BACKGROUND

Hepatitis B infection is one of the most common infections worldwide, with its vaccination being an effective preventive measure. Nonresponse to hepatitis B vaccination increases population susceptibility to virus dissemination along with detrimental complications. Despite twice intramuscular vaccination series, 14.3% in the general population and 50% in hemodialysis patients fail to mount a response against hepatitis B. We aimed to evaluate the effectiveness of intradermal (ID) vaccination in the nonresponders amongst the general and hemodialysis population.

METHODS

A total of 5 doses of 10 μg of hepatitis B vaccine was given intradermally, 2 weeks apart, to both the study groups: patients who were on hemodialysis and the general population group who previously had failed to achieve satisfactory antibody titers with the IM administration of the vaccine. A hepatitis B surface antibody (HBsAb) titer of ≥10 IU/mL and ≥100 IU/mL were considered "responder" and "good responder," respectively.

RESULTS

Out of a total of 95 participants, 49 (51.6%) were hemodialysis-dependent. Most of the participants were females 49 (51.6%). The mean age of all the participants was 39.02 ± 13.5 years (range: 18-70 years). Overall, 75.8% of the participants responded to the ID vaccination with a mean HBsAb titer of 263.5 ± 350.1 IU/L. Almost similar vaccination response was observed in both the hemodialysis and general population i.e., 75.5% and 76.1%, respectively (P = 1.00). In the hemodialysis group, the absence of hypertension (P = 0.04) and age ≥36 years (P = 0.016) were associated with an ID vaccination response.

CONCLUSION

For those not responding to the conventional IM route of the hepatitis B vaccine, the ID route is an effective way of immunization in this group and this approach would lead to a decrease in infection rates in the vulnerable population such as those on hemodialysis.

Advanced Therapeutics, Vaccinations, and Precision Medicine in the Treatment and Management of Chronic Hepatitis B Viral Infections; Where Are We and Where Are We Going?

The management of chronic hepatitis B virus (CHB) infection is an area of massive unmet clinical need worldwide. In spite of the development of powerful nucleoside/nucleotide analogue (NUC) drugs, and the widespread use of immune stimulators such as interferon-alpha (IFNα) or PEGylated interferon-alpha (PEG-IFNα), substantial improvements in CHB standards of care are still required. We believe that the future for CHB treatment now rests with advanced therapeutics, vaccination, and precision medicine, if all are to bring under control this most resilient of virus infections. In spite of a plethora of active drug treatments, anti-viral vaccinations and diagnostic techniques, the management of CHB infection remains unresolved. The reason for this is the very complexity of the virus replication cycle itself, giving rise to multiple potential targets for therapeutic intervention some of which remain very intractable indeed. Our review is focused on discussing the potential impact that advanced therapeutics, vaccinations and precision medicine could have on the future management of CHB infection. We demonstrate that advanced therapeutic approaches for the treatment of CHB, in the form of gene and immune therapies, together with modern vaccination strategies, are now emerging rapidly to tackle the limitations of current therapeutic approaches to CHB treatment in clinic. In addition, precision medicine approaches are now gathering pace too, starting with personalized medicine. On the basis of this, we argue that the time has now come to accelerate the design and creation of precision therapeutic approaches (PTAs) for CHB treatment that are based on advanced diagnostic tools and nanomedicine, and which could maximize CHB disease detection, treatment, and monitoring in ways that could genuinely eliminate CHB infection altogether.

Cross-Protection of Hepatitis B Vaccination among Different Genotypes

Hepatitis B (HB) vaccination is the most effective method for preventing HB virus (HBV) infection. Universal HB vaccination containing recombinant HB surface antigens (HBsAg) is recommended. Our data revealed that human monoclonal HB surface antibody (anti-HBs) from individuals inoculated with genotype C-based HB vaccine induced cross-protection against HBV genotype A infection. An in vitro infection model demonstrated anti-HBs-positive sera from individuals inoculated with genotype A- or C-based HB vaccine harbored polyclonal anti-HBs that could bind to non-vaccinated genotype HBV. However, because there were low titers of anti-HBs specific for HBsAg of non-vaccinated genotype, high anti-HBs titers would be required to prevent non-vaccinated genotype HBV infection. Clinically, the 2015 Centers for Disease Control and Prevention guidelines state that periodic monitoring of anti-HBs levels after routine HB vaccination is not needed and that booster doses of HB vaccine are not recommended. However, the American Red Cross suggests that HB-vaccine-induced immune memory might be limited; although HB vaccination can prevent clinical liver injury (hepatitis), subclinical HBV infections of non-vaccinated genotypes resulting in detectable HB core antibody could not be completely prevented. Therefore, monitoring anti-HBs levels after routine vaccination might be necessary for certain subjects in high-risk groups.

Mapping the epitopes of Schistosoma japonicum esophageal gland proteins for incorporation into vaccine constructs

BACKGROUND

The development of a schistosome vaccine has proved challenging but we have suggested that characterisation of the self-cure mechanism in rhesus macaques might provide a route to an effective product. The schistosome esophagus is a complex structure where blood processing is initiated by secretions from anterior and posterior glands, achieved by a mixture of ~40 unique proteins. The mechanism of self-cure in macaques involves cessation of feeding, after which worms slowly starve to death. Antibody coats the esophagus lumen and disrupts the secretory processes from the glands, potentially making their secretions ideal vaccine targets.

METHODOLOGY/PRINCIPAL FINDINGS

We have designed three peptide arrays comprising overlapping 15-mer peptides encompassing 32 esophageal gland proteins, and screened them for reactivity against 22-week infection serum from macaques versus permissive rabbit and mouse hosts. There was considerable intra- and inter-species variation in response and no obvious unique target was associated with self-cure status, which suggests that self-cure is achieved by antibodies reacting with multiple targets. Some immuno-dominant sequences/regions were evident across species, notably including: MEGs 4.1C, 4.2, and 11 (Array 1); MEG-12 and Aspartyl protease (Array 2); a Tetraspanin 1 loop and MEG-n2 (Array 3). Responses to MEGs 8.1C and 8.2C were largely confined to macaques. As proof of principle, three synthetic genes were designed, comprising several key targets from each array. One of these was expressed as a recombinant protein and used to vaccinate rabbits. Higher antibody titres were obtained to the majority of reactive regions than those elicited after prolonged infection.

CONCLUSIONS/SIGNIFICANCE

It is feasible to test simultaneously the additive potential of multiple esophageal proteins to induce protection by combining their most reactive regions in artificial constructs that can be used to vaccinate suitable hosts. The efficacy of the approach to disrupt esophageal function now needs to be tested by a parasite challenge.

Comparative analysis of the safety and efficacy of HBsAg-1018 versus HBsAg-Eng: a meta-analysis

INTRODUCTION

In addition to alum adjuvant, a wide diversity of adjuvants have been developed to enhance immune response of hepatitis B virus (HBV) vaccine in varying subjects, either in healthy vaccinators or subjects with hypo-immunity. In this context, a novel HBV vaccine HBsAg-1018, formulated with a toll-like receptor 9 agonist, was developed, and is currently in the phase of clinical trials. So, the first meta-analysis was performed to examine the safety and immune response of HBsAg-1018 among varying subjects.

MATERIAL AND METHODS

On the basis of inclusion criterion, eligible studies that reported safety and immunogenicity induced by HBsAg-1018 vaccination in randomised, controlled trials (RCTs) were involved from three databases: PubMed, EMBASE, and the Cochrane Library, and further confirmed by two reviewers. Meta-analysis was conducted using RevMan 5.3. The pooled relative risk (RR) for safety and immunogenicity was calculated using random-effects or fixed-effects models according to the heterogeneity of included studies. The methodology quality of eligible studies was assessed using the Cochrane Handbook for Systematic Reviews of Interventions version 5.1.0.

RESULTS

In total 5073 subjects administrated with HBV vaccine from four eligible publications were included in this meta-analysis. The data related to immunogenicity and safety post vaccination were pooled for meta-analysis. For safety, the combined RRs for adverse reactions were 0.98 (95% CI: 0.89-1.08), 1.02 (95% CI: 0.94-1.10) for AE, 0.88 (95% CI: 0.70-1.10) for SAE, and 1.07 (0.12-9.17) for death. No statistical heterogeneity among RCTs was found (p > 0.05). For immunogenicity, at four weeks post vaccination, seroprotection rates (SPRs) in HBsAg-1018 were significantly superior to the conventional HBV vaccine containing alum adjuvant, HBsAg-Eng (Engerix-B®, GlaxoSmithKline, Rixensart, Belgium) (RR: 4.35; 95% CI: 3.35-5.65). Furthermore, superior immunogenicity of HBsAg-1018 was maintained with RRs up to 1.23 and 95% CI: 1.20-1.27 through 28 weeks post vaccination. However, there was considerable heterogeneity with > 80% I2 value (p < 0.05).

CONCLUSIONS

In comparison with HBsAg-Eng, HBsAg-1018 exhibited superior immune response and comparable safety profile with HBsAg-Eng in varying subjects. HBsAg-1018 is an effective and safe prophylactic measure to prevent HBV infection.

Hepatitis B Vaccine and Immunoglobulin: Key Concepts

Hepatitis B virus (HBV) immunization is safe and has been accepted worldwide as a routine practice. The target of such vaccination is to induce the immune response in the host, resulting in the prevention of replication of HBV. There are several immunological and clinical factors which determine the clinical efficacy and safety of the HBV vaccine. In this article we have highlighted the response of the host immune system to HBV vaccination (immunogenicity), efficacy, and safety of the vaccine, issues with booster dosing, paths of development (preclinical and clinical) of the HBV vaccine, novel and upcoming strategies for improvement of HBV vaccination, and the concept of therapeutic HBV vaccination. The different aspects and regulatory recommendations pertaining to HBV vaccine development are also discussed. The new strategies for improvement of HBV vaccination include pre-S1 and pre-S2 portions of the HBV surface antigen, increasing the antigen dose, accelerated vaccination schedules, alternative vaccination route, use of adjuvants like immunostimulatory DNA sequences, etc. Therapeutic vaccination is being explored for initiation of a multifunctional and multispecific T cell response against the major HBV antigens and also effective activation of humoral immunity for viral control.

Persistence of Immunity for Hepatitis B Virus among Heathcare Workers and Italian Medical Students 20 Years after Vaccination

Background: Immunization of healthcare workers (HCWs) and medical students for the hepatitis B virus (HBV) is a crucial part of the hospital infection control programs. The aim of our study was to evaluate the persistence of anti-HBV specific antibodies in HCWs vaccinated during infancy or adolescence. Methods: Medical records of 734 consecutive subjects born after 1980 (481 females, 65.5% and 253 males, 34.5%) who underwent serological testing for anti-hepatitis B surface antibodies (anti-HBs) were evaluated. Results: A non-protective titer (<10 mUI) was found in 88/734 (12.0%) subjects; 84 (47.8%) of them received a booster dose of anti-hepatitis B vaccine and the anti-HBs titer of 58 subjects was measured 1 month after administration. A protective titer (anti-HBs >10 mIU/mL) was observed in almost 90% of subjects receiving the booster dose. Conclusions: A substantial percentage of HCWs had a non-protective anti-HBs titer at the time of the first employment, especially those vaccinated at birth age. However, the response to the booster dose showed that in these subjects, an anti-HBs titer <10 mIU/mL was due to the physiological decline of antibodies over the years. Therefore, primary immunization in childhood is highly effective and provides lasting immunity against HBV infection.

[Inappropriate actions in adult vaccination]

Vaccines constitute one of the main foundations of the public health system, improving the quality and life expectancy of people. The vaccination calendar must be extended to the whole life of a person and in recent years the vaccination of the adult has become more complex and requires a greater knowledge of it. The role of primary care health is essential in order to improve vaccination coverage given the patient's closeness and trust. It is important to know the recommendations on vaccination for reasons of age, underlying pathology, work circumstances or any other factor that may endanger health and be preventable by vaccination and at the same time have clear criteria of what should not be done in this countryside. An excess in vaccination can pose a risk to the health of the patient and a waste of resources.

Seroprevalence of hepatitis B and C in Nepal: a systematic review (1973-2017)

Introduction

Hepatitis B and C represent an important co-infection for people living with HIV worldwide. Nepal wants to be part of the international mobilization for viral hepatitis elimination, and has pursued better understanding of the epidemic in its territory through scientific research.

Methods

We performed a systematic review of seroprevalence studies hepatitis B and C in Nepal following the PRISMA 2009 Flow Diagram.

Results

Fifty-four scientific publications and reports were selected for this review. Nearly a quarter of these documents have been issued in recent years and many are authored by non-governmental organizations in Nepal. The collective of information displays a wide range of alarming prevalence rates, particularly for girls and women survivors of human trafficking and a progressive participation of civil society in viral hepatitis epidemiology research in the country.

Conclusion

This paper presents a most complete review of hepatitis B and C and HIV co-infection prevalence studies in different population groups from 1973 to 2016. A comprehensive analysis of the epidemiology and apparent trends in public health research and policy making in Nepal are also addressed in this document. We expect this to be a most important tool for improvements in future interventions for both epidemics in the country.

Effects of vaccine-acquired polyclonal anti-HBs antibodies on the prevention of HBV infection of non-vaccine genotypes

BACKGROUND

In universal hepatitis B (HB) vaccination, single vaccine-derived polyclonal anti-HBs antibodies (anti-HBs) need to inhibit infection of HB viruses (HBV) of non-vaccine genotypes. We experimentally addressed this issue.

METHODS

Anti-HBs-positive sera were obtained by vaccination with genotype A- or C-derived HBs antigen (HBsAg, gtA-sera or gtC-sera). Their reactivity to genotype A- and C-derived HBsAg (gtA-Ag and gtC-Ag) was measured by ELISA. The capacity of sera to neutralize HBV was evaluated using an in vitro infection model.

RESULTS

Of 135 anti-gtA-Ag-reactive gtA-sera, 134 (99.3%) were anti-gtC-Ag-reactive. All (100%) 120 anti-gtC-Ag-reactive gtC-sera were anti-gtA-Ag-reactive. The reactivity to gtA-Ag was strongly correlated with that to gtC-Ag (gtA-sera, ρ = 0.989; gtC-sera, ρ = 0.953; p < 0.01). In gtA-sera (n = 10), anti-HBs to gtA-Ag were less completely absorbed with gtC-Ag (96.4%) than with gtA-Ag (100%, p < 0.05). Similarly, in gtC-sera (n = 10), anti-HBs to gtC-Ag were less completely absorbed with gtA-Ag (96.0%) than with gtC-Ag (100%, p < 0.01). Thus, 3.6 and 4.0% of anti-HBs in gtA-sera and gtC-sera were vaccine genotype HBsAg-specific, respectively. In the neutralization test, gtA-sera (n = 4) and gtC-sera (n = 3) with anti-HBs titers adjusted to 100 mIU/mL equally inhibited genotype C HBV infection (92.8 vs. 95.4%, p = 0.44). However, at 30 mIU/mL, the gtA-sera less effectively inhibited infection than the gtC-sera (60.2 vs. 90.2%, p < 0.05).

CONCLUSIONS

Vaccination with genotype A- or C-derived HBsAg provided polyclonal anti-HBs that sufficiently bound to non-vaccine genotype HBsAg. However, a small portion of anti-HBs were specific to the vaccine genotype HBsAg. High anti-HBs titers would be required to prevent HBV infection of non-vaccine genotypes. UMIN/CTR UMIN000014363.

DNA-Loaded Cationic Liposomes Efficiently Function as a Vaccine against Malarial Proteins

The delivery of antigens as DNA vaccines is an efficient alternative to induce immune responses against antigens, which are difficult to produce in recombinant form. However, the delivery of naked DNA is ineffective or relies on sophisticated ballistic devices. Here, we show a combination of liposome application and naked DNA vaccine that successfully overcomes these problems. Upon entrapment of plasmids encoding different antigens in cationic particles, transfection efficiencies similar to commercial kits were achieved in in vitro cell cultures. The liposome-based approach provided strong humoral responses against three malarial antigens, namely the Circumsporozoite protein and the C terminus of merozoite surface protein 1 from Plasmodium vivax (titers 10⁴ or 10³–10⁴, respectively) and P. falciparum Rhoptry antigen 5 from Plasmodium falciparum (titers 10³–10⁴). When employed in P. falciparum growth-inhibition assays, antibodies demonstrated consistent reinvasion-blocking activities that were dose dependent. Liposome-formulated DNA vaccines may prove useful when targets cannot be produced as recombinant proteins and when conformation-dependent and highly specific antibodies are mandatory.

The Prevalence of Hearing Loss in Patients with Hepatitis B Infection Compared with Healthy Volunteers

INTRODUCTION

Hepatitis B virus is a virus that creates significant hepatic and extra-hepatic complications, with widespread prevalence across the community and body systemic involvement, and can impact on hearing performance. This study aims to evaluate hearing loss among individuals with hepatitis B compared with healthy subjects.

MATERIALS AND METHODS

In this case-control study, 83 HBsAg-positive patients with a 1-year history of disease were selected for pure tone audiometry (PTA) testing, while 108 HBsAg-negative patients were selected as the control group. Subjects in both groups were aged 20-40 years. The threshold was set at 25 db for hearing loss. Final data were analyzed using SPSS software.

RESULTS

Significant differences were found between the case group and control group in average PTA and hearing loss. There was also a significant difference between the two groups in average PTA at frequencies of 250, 4,000, and 8,000 Hz, but not at speech frequencies of 500, 1,000 and 2,000 Hz, despite the difference in average PTA.

CONCLUSION

According to significant differences in average PTA between patients with hepatitis B virus and healthy subjects in this study, hearing loss may be attributed to the presence HBV of in the patient group.

Current trends in hepatitis B vaccination

One of the major successes in the area of vaccinology is the emergence, development and usage of hepatitis B vaccine (a prophylactic vaccine against HBV). Hepatitis B vaccine has protected millions of individuals from acquiring HBV infection and has prevented liver cancer in the majority of vaccinated subjects. Although initially designed as prophylactic vaccines, accumulative evidence has shown that these vaccines may also be used to treat patients with chronic hepatitis B. At present, there are two main areas of discussion in hepatitis B vaccination; development of more effective prophylactic hepatitis B vaccine that can provide protection to all vaccine recipients, and designing hepatitis B-based therapeutic vaccines for treatment of chronic hepatitis B patients.

A Randomized Study Comparing the Efficacy of Three Hepatitis B Vaccine Induction Regimens in Adult Patients with Hematological Malignancies

Objective:

Non-responsiveness to hepatitis B virus (HBV) vaccines is not rare in hemato-oncological patients due to disease-associated or treatment-induced immune suppression. Although different strategies have been employed to improve the response rates, to date there is not an approved schedule for HBV immunization in patients with hematological malignancies. We designed a prospective randomized study to evaluate the efficacy of 3 different induction regimens for HBV vaccination.

Materials and Methods:

In the standard-dose (SD) group, total vaccine dose delivered was 40 µg and patients were vaccinated with 20 µg at weeks 0 and 4. In the high-dose dose-intensive (HDDI) group, total vaccine dose delivered was 80 µg and patients were vaccinated with 40 µg at weeks 0 and 4. In the high-dose time-intensive (HDTI) group, total vaccine dose delivered was 80 µg and patients were vaccinated with 20 µg at weeks 0, 2, 4, and 6.

Results:

In a cohort of 114 patients, 38.6% responded to HBV vaccination. The response rate in the SD arm, HDDI arm, and HDTI arm was 26.2%, 29.7%, and 44.4%, respectively (p>0.05). Age was the only variable identified as having a negative impact on response.

Conclusion:

Short of achieving statistical significance, a higher response rate was observed in the HDTI arm. Therefore, this study supports a high-dose, time-intensive HBV vaccine induction regimen in patients with hematological malignancies who are not on chemotherapy.

Three decades of hepatitis B control with vaccination

Hepatitis B virus (HBV) continues to represent a major health problem and can lead to acute liver failure, acute hepatitis, chronic carriership, chronic hepatitis of HBV, liver cirrhosis, liver cancer, liver transplantation and death. There is a marked difference in the geographic distribution of carriers. More than 240 million people worldwide are chronic HBV carriers. Mother-to-child transmission remains the most important mechanism of infection in countries with a high prevalence of HBV. Percutaneous/parenteral transmission and unsafe sexual practices are important mode of spread transmission of HBV in other countries. Vaccination against HBV is the gold measure for primary prevention and control of the disease. Currently, 179 countries have added HBV vaccination to their routine vaccination programs with great results. Neonatal immunization with HBV vaccine has been one of the most highly effective measures in public health and the first anti-cancer program to be launched. In this paper we review the achievements for the last three decades.