Efficacy of repeated high-dose hepatitis B vaccine (80 microg) in patients with chronic liver disease

A Quantitative Clinical Pharmacology-Based Framework For Model-Informed Vaccine Development

Historically, vaccine development and dose optimization have followed mostly empirical approaches without clinical pharmacology and model-informed approaches playing a major role, in contrast to conventional drug development. This is attributed to the complex cascade of immunobiological mechanisms associated with vaccines and a lack of quantitative frameworks for extracting dose-exposure-efficacy-toxicity relationships. However, the Covid-19 pandemic highlighted the lack of sufficient immunogenicity due to suboptimal vaccine dosing regimens and the need for well-designed, model-informed clinical trials which enhance the probability of selection of optimal vaccine dosing regimens. In this perspective, we attempt to develop a quantitative clinical pharmacology-based approach that integrates vaccine dose-efficacy-toxicity across various stages of vaccine development into a unified framework that we term as model-informed vaccine dose-optimization and development (MIVD). We highlight scenarios where the adoption of MIVD approaches may have a strategic advantage compared to conventional practices for vaccines.

Approaches for Selective Vaccinations in Cirrhotic Patients

Bacterial and viral infections are common in cirrhotic patients, and their occurrence is associated with the severity of liver disease. Bacterial infection may increase the probability of death by 3.75 times in patients with decompensated cirrhosis, with ranges of 30% at 1 month and 63% at 1 year after infection. We illustrate the indications and the modalities for vaccinating cirrhotic patients. This topic is important for general practitioners and specialists.

Efficacy of Hepatitis B Virus Vaccines HBVaxpro40© and Fendrix© in Patients with Chronic Liver Disease in Clinical Practice

Chronic liver disease results in a low response rate to the hepatitis B virus vaccine. Information on the efficacy of the double adjuvanted vaccine FENDRIX® (3-O-desacyl-4'-monophosphoryl lipid A and aluminum phosphate) and single adjuvant HBVAXPRO®40 (aluminum hydroxyphosphate sulfate) in chronic liver disease is scarce. The primary aim of this prospective study in clinical practice was to evaluate the effectiveness of HBVAXPRO®40 and FENDRIX® in this setting. Patients received HBVAXPRO® (0, 1 and 6 months) or FENDRIX® (0, 1, 2 and 6 months) depending on availability. Clinical data and anti-HBs levels were collected at 2, 6 and 12 months. A total of 125 patients were included (mean age 61.8 years; 57.6% males; 43.2% liver cirrhosis; 75.9% Child A and 24.1% Child B): 76 were vaccinated with HBVAXPRO® and 49 with FENDRIX®. There were no significant differences between the two vaccines. The overall response rates at 2, 6 and 12 months were 76.8, 72.8 and 59.2%, respectively. In the univariate analysis, active alcohol intake, alcohol etiology, liver cirrhosis and ultrasound signs of portal hypertension were associated with a lower response to vaccination, whereas in the multivariate analysis, liver cirrhosis was the only factor that significantly increased the likelihood of nonresponse (OR 10.5). HBVAXPRO® and FENDRIX® are good options for HBV vaccination in patients with chronic liver disease.

Immunogenicity of varicella zoster vaccine in pediatric liver transplantation

BACKGROUND

Pediatric liver transplant (LT) candidates often miss complete varicella-zoster virus (VZV) vaccination before LT. We aimed to evaluate the immunogenicity of two doses of VZV vaccines in pediatric LT candidates younger than 2 years and persistence of its immunogenicity after LT.

METHODS

Patients aged 9-24 months were enrolled before LT. The first dose of VZV vaccine was given at 9 months, and the second dose was given at between 1 to 3 months later, and at least 4 weeks before LT. Varicella-zoster IgG (VZG) was used to detect immunoglobulin G antibodies to VZV and was reported as a test value (TV). A test value ≥ 0.9 was considered as seropositive. TV was measured at enrollment, 1 month after the first and the second dose of VZV vaccine, before LT, and 3 and 6 months after LT.

RESULTS

Fourteen children were enrolled in this prospective cohort study. The median age at the first and the second dose of VZV vaccine was 11.5 months (IQR 9-12) and 13 months (IQR 12-33), respectively. The seroconversion rate was 66.7% (8/12) and 70% (7/10) after the first and second VZV vaccine doses, respectively. Seven of nine patients who underwent LT had two doses of VZV vaccine. Six patients were seropositive before LT, which persisted at 3 to 6 months after LT. Of two patients who received only one dose, TV was not detected after LT.

CONCLUSIONS

The two doses of VZV vaccine appeared to be more immunogenic than one dose in pediatric LT candidates aged less than 2 years.

Efficacy of an accelerated double-dose hepatitis B vaccine regimen in patients with cirrhosis

The hepatitis B (HBV) vaccine is recommended in unvaccinated adults with cirrhosis, despite its low efficacy. We aimed to evaluate the response to a double-dose/accelerated vaccine schedule in patients with cirrhosis admitted into a hepatology ward. All patients with cirrhosis admitted to the hepatology ward without exclusion criteria were offered the HBV HBVAXPRO 40mcg vaccine at months 0, 1 and 2. Non-responders received a second cycle. We evaluated 468 patients and only 19% were seroprotected against HBV. In 196 patients without exclusion criteria for HBV vaccination, the per protocol response rate (anti-HBs >10 U/ml) was 23% after a first cycle and 59% after a second cycle. The overall response per intention to treat was only 23%. We have not identified predictors of response. Only one patient had a mild adverse event. Most patients with cirrhosis admitted in the hepatology ward are unprotected against HBV. Although a second HBV vaccination cycle increases the response rate, the poor overall response reinforces the implementation of HBV vaccination before the development of cirrhosis.

Predicting related factors of immunological response to hepatitis B vaccine in hemodialysis patients based on integration of decision tree classification and logistic regression

The non/hypo-response rate of the hepatitis B vaccine among hemodialysis (HD) patients is still high, it is of great significance to explore the influencing factors and their relationships. To study the related factors and their relationships using logistic regression model and Chi-squared Automatic Interaction Detection (CHAID) decision tree model. A randomized controlled trial was conducted between February 2014 and May 2015 in China. HD patients being serologically negative for HBsAg and anti-HBs were randomly assigned to receive three intramuscular injections of the standard dose (20 µg) or high dose (60 µg) of recombinant hepatitis B vaccine at months 0, 1, and 6. Those with anti-HBs concentrations <100 mIU/mL, and ≥100 mIU/mL at month 7 were considered as non/hypo-response and high-level response, respectively. The non/hypo-response was 31.34% (89/284). After adjustment for confounders, logistic analysis showed that males (OR = 2.203, 95%CI: 1.109-4.367) and those with higher dialysis frequency (>4 times per 2 weeks) (OR = 1.918, 95%CI: 1.015-3.626) had a significant risk of non/hypo-response. While the CHAID analysis showed that gender, dose, and dialysis frequency were influencing factors of non/hypo-response, and gender is most important. The interaction between gender and dialysis frequency had the greatest effect on immunization, and followed by the interaction between dialysis frequency and vaccine dose. Taken together, gender, dose and dialysis frequency were influencing factors of hepatitis B vaccine in HD patients.

NEW IMMUNIZATION SCHEDULE EFFECTIVENESS AGAINST HEPATITIS B IN LIVER TRANSPLANTATION PATIENTS

BACKGROUND

Although liver transplantation is considered to be a high-risk procedure, it is well-established as a treatment option for the cure and quality of life enhancement for individuals who suffer from diseases. Preventing an infection by hepatitis B virus through immunization schedules has been the most effective way to reduce complications, since it decreases the number of people who suffer from chronic hepatitis caused by the hepatitis B virus and eradicates its transmission.

OBJECTIVE

1. Analyzing evidence in the literature on various schedules employed for immunization against hepatitis B in patients who have received a liver transplantation. 2. Suggesting potential immunization schedules against hepatitis B in patients who suffer from liver cirrhosis, without previous verifying documentation, using the Child-Turcotte Pugh score, according to evidences found in the literature.

METHODS

Systematic review of the literature, conducted on the data bases MedLine, PubMed, and Lilacs, between September, 2017 and January, 2018, by using the following keywords: "Liver Transplantation, "Immunization Schedule", "Hepatitis B Vaccines". In order to analyze the articles, a summary figure was especially designed and both the results and discussion were presented in a descriptive way.

RESULTS

We included 24 studies; among them, eight had accelerated immunization schedules, 13 followed the conventional schedules, and three had super accelerated schedules. Regarding immunization, 21 studies were conducted with patients in the pre-transplant period, one with a transplanted patient, one with a pre-transplant group, and one with a post-transplant group. Found articles suggest that, disregarding the chosen immunization schedule, seroconversion rates tended to be lower as the liver disease advanced, compared to the healthy population.

CONCLUSION

The studies did not find seroconversion superiority between the different immunization schedules (conventional and unconventional). However, since candidates to liver transplantation are usually very vulnerable, results show that super accelerated immunization schedules are possibly recommended for such group of patients; serologic test results will be higher when the immunization schedule is completed in the pre-transplant period.

Enhanced immune response to hepatitis B vaccination through immunization with a Pre-S1/Pre-S2/S vaccine

Efficacy and safety of recombinant yeast-derived hepatitis B vaccines for prevention of hepatitis B have been demonstrated unequivocally worldwide as reflected in reduction in HBsAg carrier rates and hepatocellular carcinoma. A new generation of recombinant HBV vaccines expressed in mammalian cells containing Pre-S/S epitopes has been developed in several countries. Such vaccines are useful in special risk groups, i.e., in non-responders to conventional HBV vaccines including older adults, obese people, health care workers, patients with renal failure and on dialysis, transplant patients, patients with HIV as well as travelers on short notice to HBV endemic regions. The future of such vaccines depends on their enhanced immunogenicity and cost profile. Sci-B-Vac™ is a mammalian cell-derived recombinant Pre-S1/Pre-S2/S hepatitis B vaccine which has been shown to be highly immunogenic, inducing faster and higher seroprotection rates against HBV with higher anti-HBs levels at lower HBsAg doses as compared to conventional yeast-derived vaccines. Recently, it has been suggested that such Pre-S/S vaccines against HBV might be efficacious not only for prevention but also for intervention in persistent HBV infection. Data obtained in a recent clinical trial conducted in Vietnam in patients with chronic hepatitis B suggest that repeated monthly i.m. injections of the Sci-B-Vac™ co-administered with daily oral lamivudine treatment can suppress HBV replication and lead to anti-HBs seroconversion in ~50 % of treated patients. Optimization of protocols and efficacy of such an intervention, intended to bypass T cell exhaustion and immune tolerance to HBV remains to be explored.

Hepatitis B vaccine by intradermal route in non responder patients: An update

Vaccination is the main prophylactic measure to reduce the mortality caused by hepatitis B virus (HBV) infection in healthy subjects since the immune response to hepatitis B recombinant vaccination occurs in over 90% of general population. Individuals who develop an anti-HBs titer less than 10 mIU/mL after primary vaccination cycle are defined “no responders”. Many factors could cause a non response to the HBV vaccination, such as administration of the vaccine in buttocks, impaired vaccine storage conditions, drug abuse, smoking, infections and obesity. Moreover there are some diseases, like chronic kidney disease, human immunodeficiency virus infection, chronic liver disease, celiac disease, thalassaemia, type I diabetes mellitus, down’s syndrome and other forms of mental retardation that are characterized by a poorer response to HBV vaccination than healthy subjects. To date it is still unclear how to treat this group of patients at high risk of hepatitis B infection. Recent studies seem to indicate that the administration of HBV recombinant vaccine by the intradermal route is very effective and could represent a more useful strategy than intramuscular route. This review focuses on the use of anti hepatitis B vaccine by intradermal route as alternative to conventional intramuscular vaccine in all non responder patients. A comprehensive review of the literature using PubMed database, with appropriate terms, was undertaken for articles in English published since 1983. The literature search was undertaken in September 2013.

Management of infections in cirrhotic patients: report of a consensus conference

The statements produced by the consensus conference on infection in end-stage liver disease promoted by the Italian Association for the Study of the Liver, are here reported. The topics of epidemiology, risk factors, diagnosis, prophylaxis, and treatment of infections in patient with compensated and decompensated liver cirrhosis were reviewed by a scientific board of experts who proposed 26 statements that were graded according to level of evidence and strength of recommendation, and approved by an independent jury. Each topic was explored focusing on the more relevant clinical questions. By systematic literature search of available evidence, comparison and discussion of expert opinions, pertinent statements answering specific questions were presented and approved. Short comments were added to explain the basis for grading evidence particularly on case of controversial areas.

2013 IDSA clinical practice guideline for vaccination of the immunocompromised host

An international panel of experts prepared an evidenced-based guideline for vaccination of immunocompromised adults and children. These guidelines are intended for use by primary care and subspecialty providers who care for immunocompromised patients. Evidence was often limited. Areas that warrant future investigation are highlighted.

Acinetobacter baumannii rOmpA vaccine dose alters immune polarization and immunodominant epitopes

BACKGROUND

The rOmpA vaccine has been shown to protect mice from lethal infection caused by extreme-drug-resistant (XDR) Acinetobacter baumannii. The role of dose in immunology of the rOmpA vaccine was explored.

METHODS

Mice were vaccinated with various doses of rOmpA plus aluminum hydroxide (Al(OH)(3)) adjuvant. The impact of dose on antibody titers, cytokine production, and immunodominant epitopes was defined.

RESULTS

Anti-rOmpA IgG and IgG subtype titers were higher at larger vaccine doses (30 and 100 μg vs. 3 μg). The 3 μg dose induced a balanced IFN-γ-IL-4 immune response while the 100 μg dose induced a polarized IL-4/Type 2 response. Epitope mapping revealed distinct T cell epitopes that activated IFN-γ-, IL-4-, and IL-17-producing splenocytes. Vaccination with the 100 μg dose caused epitope spreading among IL-4-producing splenocytes, while it induced fewer reactive epitopes among IFN-γ-producing splenocytes.

CONCLUSIONS

Vaccine dose escalation resulted in an enhanced Type 2 immune response, accompanied by substantial IL-4-inducing T cell epitope spreading and restricted IFN-γ-inducing epitopes. These results inform continued development of the rOmpA vaccine against A. baumannii, and also are of general importance in that they indicate that immune polarization and epitope selectivity can be modulated by altering vaccine dose.

Efficacy of high-dose intra-dermal hepatitis B virus vaccine in previous vaccination non-responders with chronic liver disease

BACKGROUND

Hepatitis B virus (HBV) vaccination is essential in chronic liver disease (CLD), because it can help prevent acute-on-chronic disease, which has potentially fatal complications. Unfortunately, this group has a significant proportion of HBV vaccination non-responders. A variety of intra-muscular (IM) vaccination methods have been used in an attempt to remedy this poor-response, but with limited success.

AIMS

Herein is reported the safety and efficacy of high-dose intra-dermal (ID) HBV vaccination in CLD individuals who had failed previous IM standard and boost-dosing regimens.

METHODS

Forty-eight CLD individuals, known HBcAb negative, who had failed both a three-dose schedule of 40 μg IM vaccination, and boost dosing of either 40 or 80 μg IM, were identified, of which 42 completed the vaccination course. Each received a 40 μg ID total dose (20 μg per arm) during their clinic visits until a response was documented or a maximum of three doses had been administered. HBsAb titer ≥ 10 mIU/ml was regarded as an immunologic response; the intention was to achieve an optimum response of ≥ 100 mIU/ml.

RESULTS

Twenty-nine of forty-two (69%) individuals had an immunologic response, with 15 (51%) of the responders having the optimum response. No changes in serologic data occurred. No serious dermatologic reactions were observed. No differences between those who responded and those who did not were observed with regard to the presence of cirrhosis, diabetes mellitus, or chronic kidney disease.

CONCLUSIONS

High-dose ID HBV vaccination of previous CLD non-responders to the standard IM regimen with boost dosing is both safe and efficacious, and should be considered for all such groups.

Extra-high-dose hepatitis B vaccination does not confer longer serological protection in peritoneal dialysis patients: a randomized controlled trial

BACKGROUND

The response to recombinant hepatitis B vaccine remains suboptimal among the dialysis population.

METHODS

In this multi-centre randomized controlled trial, we studied the factors that modify the response to intramuscular Engerix-B vaccination in patients on peritoneal dialysis. The primary aim was to study if a three-dose schedule of extra-high dose (80 microg) of Engerix-B would offer better primary seroconversion and more persistent serological protection than the conventional 40-microg dose.

RESULTS

Forty-two peritoneal dialysis patients were randomized to receive the conventional 40-microg Engerix-B dose and 45 patients to 80-microg dose. Seroconversion [hepatitis B surface antibody (anti-HBs) level > or =10 IU/l 3 months after completion of the third dose] occurred in 78.6% of patients after 40-microg Engerix-B dosage treatment versus 62.2% for those receiving 80-microg Engerix-B treatment (P = 0.11). After 12 months, the persistence of protective anti-HBs also did not differ between 40- (45.2%) and 80-microg (51.1%) treatment groups (P = 0.67). In contrast, patients with seroconversion 3 months after the third dose of Engerix-B had a higher normalized protein nitrogen appearance (nPNA) than patients without seroconversion (1.16 +/- 0.25 versus 0.96 +/- 0.23 g/kg/day, P = 0.001). Conclusions. We found no evidence of a worthwhile clinical benefit from increasing the three-dose intramuscular Engerix-B vaccine from 40- to 80-microg dose. An unplanned analysis suggested a role of improved protein intake to improve the immune response to hepatitis B vaccine in peritoneal dialysis patients.

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

Hepatitis B virus infection is a global health problem. Worldwide, about 360 million people are chronically infected with the virus. They continue to spread the virus to others and are themselves at risk of chronic liver diseases and hepatocellular carcinoma. The infection can now be treated by antivirals or interferons and the transmission route can be interrupted. Nevertheless, the most effective means is to immunize all susceptible individuals, especially young children, with safe and efficacious vaccines. The combined efforts of vaccination, effective treatment and interruption of transmission make elimination of the infection plausible and may eventually lead to eradication of the virus. Because hepatitis B vaccination has a key role in the control of hepatitis B, properties of this vaccine, its effectiveness in pre-exposure and post-exposure settings, duration of protection after vaccination and the need of booster doses are discussed. Mass hepatitis B vaccination in children decreases the carriage of the virus, and the diseases associated with acute and chronic infection, including hepatocellular carcinoma. Challenges that need to be solved to expand mass vaccination, and the strategies towards elimination and eventual eradication of hepatitis B in the world are also discussed.