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HBV Vaccine (hbv + vaccine)
Selected AbstractsEfficacy and long-term immunogenicity of hepatitis B vaccine in haemodialysis patientsINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 3 2009A. Ramezani Summary Background:, Hepatitis B vaccine is effective in protection against hepatitis B virus (HBV) infection in haemodialysis (HD) patients, but the antibody response is variable in this population and the persistence of immunity in them remains largely unknown. In this study we aimed to evaluate the efficacy and long-term immunogenicity of hepatitis B vaccine in HD patients. Methods:, In this study, we initially offered HBV vaccination as double dose, four vaccine series schedule (40 ,g injections intramuscularly in the deltoid muscle at 0, 1, 2 and 6 months) to 54 HD patients who were negative for hepatitis B core antibody and did not receive any dose of HBV vaccine previously. Serum levels of hepatitis B surface antibody (anti-HBs) tested 1,2 months after completion of vaccination. Then we follow the patients up to 1 year after primary vaccination to evaluate the persistence of immunity (as indicated by serum levels of anti-HBs higher than or equal to 10 IU/l). Results:, After primary vaccination, 87% of patients developed anti-HBs levels above 10 IU/l. 27.8% and 59.2% of them were weak responders and high responders respectively. 13% of patients were non-responders. After 1-year follow-up, 18.18% of responders had lost their anti-HBs (transient responders). All of them were initially in weak responders group and had lower anti-HBs levels. Conclusion:, We found an average percentage of seroconversion after primary HBV vaccination in HD patients. Our study also supported this fact that an antibody titre above 100 IU/l following primary vaccination is necessary to maintain that level of antibody 1 year later. [source] Meta-analysis: levamisole improves the immune response to hepatitis B vaccine in dialysis patientsALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 6 2010F. Fabrizi Summary Background, Patients undergoing maintenance dialysis often fail to mount protective antibodies to hepatitis B virus surface antigen (HBsAg) following vaccination against hepatitis B virus (HBV). Some authors have suggested that levamisole improves immune response to HBV vaccine in dialysis population. However, consistent information on this issue does not exist. Aim, To evaluate efficacy and safety of levamisole as adjuvant to hepatitis B virus (HBV) vaccine in dialysis patients by performing a systematic review of the literature with a meta-analysis of clinical trials. Methods, We used the random-effects model of DerSimonian and Laird, with heterogeneity and sensitivity analyses. Only trials comparing the seroresponse rate in study subjects (levamisole plus HBV vaccine) vs. controls (HBV vaccine alone) were included. The end point of interest was the rate of patients showing seroprotective anti-hepatitis B titres at completion of HBV vaccine schedule in study vs. control groups. Results, We identified four studies involving 328 unique patients on regular dialysis. Only prospective, randomized clinical trials (RCTs) were included. Pooling of study results showed a significant increase in response rates among study (levamisole plus HBV vaccine) vs. control (HBV vaccine alone) patients; the pooled Odds Ratio was 2.432 (95% Confidence Intervals, 1.34; 4.403), P = 0.002. No study heterogeneity was found. These results did not change in various subgroups of interest. Conclusions, Our meta-analysis showed that levamisole significantly improves immune response to hepatitis B vaccine in dialysis population. The limited number of patients precluded more conclusions. [source] Targeted destruction of the polymerized human serum albumin binding site within the preS2 region of the HBV surface antigen while retaining full immunogenicity for this epitopeJOURNAL OF VIRAL HEPATITIS, Issue 1 2003J.-H. Park summary. The 55-amino acid (a.a.) preS2 region of the hepatitis B virus (HBV) envelope protein is highly immunogenic, and antibodies against this epitope confer seroprotection against HBV infections. Accordingly, various experimental and clinical studies for developing and evaluating HBV vaccines that include this particular epitope have been reported. However, a pitfall in using preS2 epitopes as part of a vaccinating antigen is that polymerized human serum albumin (pHSA), which is a normal constituent of the human serum, binds to and makes complexes with this particular region. Consequently, it is most likely that the antigen epitope is masked by serum pHSA and subsequently not detected by the immune system. To overcome these limitations, a novel single a.a substitute of the preS2 region was designed that corresponds to a tyrosine to serine exchange at position 140 of preS2. Competitive enzyme-linked immunosorbent assay showed that this substitution completely abolishes pHSA-binding activities in the mutated preS2 peptide, and CD spectra analysis revealed that this property might have been induced by slight conformational changes in its secondary structure. Nevertheless, the original B-cell epitope was still preserved in the mutated preS2 as determined by experimental immunization in mice. In this regard, the preS2(120,145/Y140S) sequence may be an HBV vaccine where epitopes, with intrinsic properties have been deleted without affecting the immunogenicity of the epitope itself. It is expected that the inclusion of this point mutated preS2 epitope will improve the efficacy of conventional preS2-containing HBV vaccines. [source] Active Immunization to Prevent De Novo Hepatitis B Virus Infection in Pediatric Live Donor Liver RecipientsAMERICAN JOURNAL OF TRANSPLANTATION, Issue 1 2007C.-C. Lin This study aims to evaluate the efficacy of HBV vaccination as an alternative preventive measure against de novo HBV infection in pediatric living donor liver transplantation (LDLT). Sixty recipients were enrolled in this study. Thirty received grafts from anti-HBc(+) donors, and another 30 received grafts from anti-HBc(,) donors. HBV vaccine was given pretransplant to every candidate. Posttransplant, lamivudine was routinely given to recipients receiving anti-HBc(+) grafts for about 2 years. Forty-seven (78%) recipients achieved high levels of anti-HBs titer (>1000 IU/L). Two (3.3%) recipients developed de novo HBV infection where one received an anti-HBc(,) graft and another received an anti-HBc(+) graft. Both recipients were in the lower anti-HBs titer group (<1000 IU/L). The incidence of de novo HBV infection was significantly higher in the lower titer group (15.4% vs. 0%, p = 0.04). The median follow-up period was 51 months in recipients with anti-HBc(,) grafts and 57 months in those with anti-HBc(+) grafts. Active immunization is an effective method to prevent de novo HBV infection. It can result in high levels of anti-HBs titer (>1000 IU/L) which may prevent de novo HBV infection in pediatric patients with efficient primary vaccination undergoing LDLT. [source] An accelerated hepatitis B vaccination schedule for young drug usersAUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 4 2005Nich Rogers Objective: Jo determine completion rates for an accelerated hepatitis B vaccine (HBV) program among a population of young drug users. Design: Between January 2001 and May 2002, a three-dose course of HBV vaccine (0, 7 and 21 days) was offered free to all drug users (aged 22 years or younger) accessing two outreach sites of a youth-focused support and drug treatment service in metropolitan Melbourne, Australia. Clients were offered vaccination in any safe environment of their choice. An audit was conducted on the health records of participating clients. Main outcome measures: Number of completed vaccinations; settings in which vaccinations were completed. Results: Ninety young people accepted vaccination, with 71% completing the full course. The majority preferred to receive vaccination at drug treatment outreach sites (53%). Conclusions: An accelerated vaccination schedule appears acceptable to young drug users, suggesting that vaccination programs can be successful when barriers to immunisation are appropriately identified and addressed. [source] Targeted destruction of the polymerized human serum albumin binding site within the preS2 region of the HBV surface antigen while retaining full immunogenicity for this epitopeJOURNAL OF VIRAL HEPATITIS, Issue 1 2003J.-H. Park summary. The 55-amino acid (a.a.) preS2 region of the hepatitis B virus (HBV) envelope protein is highly immunogenic, and antibodies against this epitope confer seroprotection against HBV infections. Accordingly, various experimental and clinical studies for developing and evaluating HBV vaccines that include this particular epitope have been reported. However, a pitfall in using preS2 epitopes as part of a vaccinating antigen is that polymerized human serum albumin (pHSA), which is a normal constituent of the human serum, binds to and makes complexes with this particular region. Consequently, it is most likely that the antigen epitope is masked by serum pHSA and subsequently not detected by the immune system. To overcome these limitations, a novel single a.a substitute of the preS2 region was designed that corresponds to a tyrosine to serine exchange at position 140 of preS2. Competitive enzyme-linked immunosorbent assay showed that this substitution completely abolishes pHSA-binding activities in the mutated preS2 peptide, and CD spectra analysis revealed that this property might have been induced by slight conformational changes in its secondary structure. Nevertheless, the original B-cell epitope was still preserved in the mutated preS2 as determined by experimental immunization in mice. In this regard, the preS2(120,145/Y140S) sequence may be an HBV vaccine where epitopes, with intrinsic properties have been deleted without affecting the immunogenicity of the epitope itself. It is expected that the inclusion of this point mutated preS2 epitope will improve the efficacy of conventional preS2-containing HBV vaccines. [source] | ||||||||||