The effect of age on immunologic response to recombinant hepatitis B vaccine: a meta-analysis

Vaccines for the elderly: current use and future challenges

Age-related changes of the immune system contribute to increased incidence and severity of infections in the elderly. Vaccination is the most effective measure to prevent infections and vaccination recommendations in most countries include specific guidelines for the elderly. Vaccination against influenza and Streptococcus pneumoniae is usually recommended for persons with underlying diseases and for the elderly with heterogeneous age limits between ≥ 50 years and ≥ 65 years. Some countries also recommend vaccination against herpes zoster. Several vaccines are recommended for all adults, such as regular booster shots against tetanus/diphtheria/pertussis/polio, or for specific groups, e.g. vaccination against tick-borne encephalitis in endemic areas or travel vaccines. These are also relevant for the elderly. Most currently used vaccines are less immunogenic and effective in the elderly compared to younger adults. Potential strategies to improve their immunogenicity include higher antigen dose, alternative routes of administration, and the use of adjuvants, which were all implemented for influenza vaccines, and induce moderately higher antibody concentrations. Research on universal vaccines against influenza and S. pneumoniae is ongoing in order to overcome the limitations of the current strain-specific vaccines. Respiratory syncytial virus causes significant morbidity in the elderly. Novel vaccines against this and other pathogens, for instance bacterial nosocomial infections, have tremendous potential impact on health in old age and are intensively studied by many academic and commercial organizations. In addition to novel vaccine developments, it is crucial to increase awareness for the importance of vaccination beyond the pediatric setting, as vaccination coverage is still far from optimal for the older population.

Immunogenicity of a two-dose investigational hepatitis B vaccine, HBsAg-1018, using a toll-like receptor 9 agonist adjuvant compared with a licensed hepatitis B vaccine in adults

BACKGROUND

Hepatitis B virus infection remains an important public health problem in the United States. Currently approved alum-adjuvanted vaccines require three doses and have reduced immunogenicity in adults, particularly in those who have diabetes mellitus, or are older, male, obese, or who smoke.

METHODS

Phase 3 observer-blinded, randomized (2:1 HBsAg-1018 [HEPLISAV-B™]:HBsAg-Eng [Engerix-B®]), active-controlled trial in adults 18-70 years of age. HBsAg-1018 was administered intramuscularly at weeks 0 and 4 and placebo at week 24 and HBsAg-Eng at weeks 0, 4, and 24. The primary immunogenicity endpoint assessed the noninferiority of the seroprotection rate at week 28 in participants with type 2 diabetes mellitus. Secondary endpoints included seroprotection rates in the total trial population and by age, sex, body mass index, and smoking status.

RESULTS

Among 8374 participants randomized, 961 participants in the per-protocol population had type 2 diabetes mellitus. In diabetes participants, the seroprotection rate in the HBsAg-1018 group at week 28 was 90.0%, compared with 65.1% in the HBsAg-Eng group, with a difference of 24.9% (95% CI: 19.3%, 30.7%), which met the prospectively-defined criteria for noninferiority and statistical significance. In the total study per-protocol population (N = 6826) and each pre-specified subpopulation, the seroprotection rate in the HBsAg-1018 group was statistically significantly higher than in the HBsAg-Eng group.

CONCLUSION

Two doses of HBsAg-1018, administered over 4 weeks, induced significantly higher seroprotection rates than three doses of HBsAg-Eng, given over 24 weeks, in adults with factors known to reduce the immune response to hepatitis B vaccines as well as in those without those factors. With fewer doses in a shorter time, and greater immunogenicity, HBsAg-1018 has the potential to significantly improve protection against hepatitis B in adults at risk for hepatitis B infection. Trial Registration clinicaltrials.gov Identifier: NCT02117934.

Robust Antibody and Cytokine Response to Hepatitis B Vaccine Among Not-in-Treatment Patients With Chronic Hepatitis C: An Open-Label Control Study in China

Background

Hepatitis B vaccine is an effective measure to prevent hepatitis B virus infection. Whether chronic hepatitis C virus (HCV) infection decreases humoral and cell-mediated immunity responses to hepatitis B vaccination is still controversial.

Methods

Patients with chronic HCV infection who were not in treatment and healthy controls, matched at a 1:2 ratio for community, sex, and age (within 5 years), were identified from a community-based screening. All participants received 3 doses of hepatitis B vaccine. Antibody to hepatitis B surface antigen was tested 1 month after the third vaccine dose and was compared between 2 groups. Spot-forming cells (SFCs) of interferon γ and interleukin 2, 4, 5, and 6 were counted by means of enzyme-linked immunospot, and SFC counts were compared between the 2 groups.

Results

The rates of nonresponse and low, normal, and high response were 3.80%, 10.13%, 45.57%, and 40.50% respectively, in the HCV group, and the corresponding rates in the healthy control group were 1.26%, 10.13%, 39.24%, and 49.37% (all P > .05). There were no significant differences in SFC counts between the 2 groups for interferon γ or interleukin 2, 4, or 5 (all P > .05).

Conclusions

This study provided preliminary evidence of the good immunogenicity and safety of hepatitis B vaccination among patients in China with chronic hepatitis C who are not in treatment.

Clinical Trials Registration

NCT 02898922.

The Immune Response of Vaccination Against Hepatitis B virus in Iranian Patients Undergoing Chemotherapy

Introduction:

Hepatitis B virus (HBV) infection and its complications are major public health problems. As it is hard to treat and control the chronic state, control of disease depends on the prevention especially by vaccination. There is an impaired immune response to vaccinations including HBV in patients with some malignancies. The aim of this study is to assess the response rate of patients undergoing chemotherapy to HBV vaccination.

Materials and Methods:

All patients from two hematology/oncology clinics in Isfahan, Iran with the history of at least 1 month chemotherapy who had the inclusion criteria were enrolled in a case control study. Also a sex- and age-matched control group from healthy population was selected. They were vaccinated in a schedule of 0, 1, and 6 months and were examined for antibody titers 1 month after the last dose. The titers more than 10 mIU/ml were determined as positive response to vaccination.

Results:

In this study, 50 patients and 50 healthy subjects were enrolled. The two groups were age and sex matched (P > 0.05). Frequency of negative responses to HBV vaccination in case and control groups were 9 (18%) and 1 (2%), respectively (OR = 10.75, CI = 1.30–88.47, P = 0.027). Of 50 patients, 54%, 12%, 22%, and 12% had breast cancer, lymphoma, gastrointestinal, and genitourinary cancers, respectively, and frequency of negative responses were 3 (11%), 1 (16%), 4 (36.4%), and 1 (16%), respectively (P = 0.167).

Conclusion:

According to our results, malignancy and chemotherapy will have an important effect on the immune system and cause negative response to HBV vaccination. Our results revealed the importance of passive immunity and screening for HBV infection in patients undergoing chemotherapy. Also more studies for better vaccination schedules in this group of patients are recommended.

The in vitro MIMIC® platform reflects age-associated changes in immunological responses after influenza vaccination

Increasing research and development costs coupled with growing concerns over healthcare expenditures necessitate the generation of pre-clinical testing models better able to predict the efficacy of vaccines, drugs and biologics. An ideal system for evaluating vaccine immunogenicity will not only be reliable but also physiologically relevant, able to be influenced by immunomodulatory characteristics such as age or previous exposure to pathogens. We have previously described a fully autologous human cell-based MIMIC® (Modular IMmune In vitro Construct) platform which enables the evaluation of innate and adaptive immunity in vitro, including naïve and recall responses. Here, we establish the ability of this module to display reduced antibody production and T cell activation upon in vitro influenza vaccination of cells from elderly adults. In the MIMIC® system, we observe a 2.7-4.2-fold reduction in strain-specific IgG production to seasonal trivalent influenza vaccine (TIV) in the elderly when compared to adults, as well as an age-dependent decline in the generation of functional antibodies. A parallel decline in IgG production with increasing age was detected via short-term ex vivo stimulation of B cells after in vivo TIV vaccination in the same cohort. Using MIMIC®, we also detect a reduction in the number but not proportion of TIV-specific multifunctional CD154⁺IFNγ⁺IL-2⁺TNFα⁺ CD4⁺ T cells in elderly adults. Inefficient induction of multifunctional helper T cells with TIV stimulation in MIMIC® despite a normalized number of initial CD4⁺ T cells suggests a possible mechanism for an impaired anti-TIV IgG response in elderly adults. The ability of the MIMIC® system to recapitulate differential age-associated responses in vitro provides a dynamic platform for the testing of vaccine candidates and vaccine enhancement strategies in a fully human model including the ability to interrogate specific populations, such as elderly adults.

Humoral Immunity to Primary Smallpox Vaccination: Impact of Childhood versus Adult Immunization on Vaccinia Vector Vaccine Development in Military Populations

Modified Vaccinia virus has been shown to be a safe and immunogenic vector platform for delivery of HIV vaccines. Use of this vector is of particular importance to the military, with the implementation of a large scale smallpox vaccination campaign in 2002 in active duty and key civilian personnel in response to potential bioterrorist activities. Humoral immunity to smallpox vaccination was previously shown to be long lasting (up to 75 years) and protective. However, using vaccinia-vectored vaccine delivery for other diseases on a background of anti-vector antibodies (i.e. pre-existing immunity) may limit their use as a vaccine platform, especially in the military. In this pilot study, we examined the durability of vaccinia antibody responses in adult primary vaccinees in a healthy military population using a standard ELISA assay and a novel dendritic cell neutralization assay. We found binding and neutralizing antibody (NAb) responses to vaccinia waned after 5–10 years in a group of 475 active duty military, born after 1972, who were vaccinated as adults with Dryvax®. These responses decreased from a geometric mean titer (GMT) of 250 to baseline (<20) after 10–20 years post vaccination. This contrasted with a comparator group of adults, ages 35–49, who were vaccinated with Dryvax® as children. In the childhood vaccinees, titers persisted for >30 years with a GMT of 210 (range 112–3234). This data suggests limited durability of antibody responses in adult vaccinees compared to those vaccinated in childhood and further that adult vaccinia recipients may benefit similarly from receipt of a vaccinia based vaccine as those who are vaccinia naïve. Our findings may have implications for the smallpox vaccination schedule and support the ongoing development of this promising viral vector in a military vaccination program.

Diagnostic performance of serological assays for anti-HBs testing: Results from a quality assessment program

BACKGROUND

Post-vaccination testing after hepatitis B vaccination is indispensable to evaluate long-term immunological protection. Using a threshold level of antibodies against hepatitis B surface antigen (anti-HBs) to define serological protection, implies reproducible and valid measurements of different diagnostic assays.

OBJECTIVES

In this study we assess the performance of currently used anti-HBs assays.

STUDY DESIGN

In 2013, 45 laboratories participated in an external quality assessment program using pooled anti-HBs serum samples around the cutoff values 10IU/l and 100IU/l. Laboratories used either Axsym (Abbott Laboratories), Architect (Abbott Laboratories), Access (Beckman-Coulter), ADVIA Centaur anti-HBs2 (Siemens Healthcare Diagnostics), Elecsys, Modular or Cobas (Roche Diagnostics) or Vidas Total Quick (Biomerieux) for anti-HBs titre quantification. We analysed covariance using mixed-model repeated measures. To assess sensitivity/specificity and agreement, a true positive or true negative result was defined as an anti-HBs titre respectively above or below the cutoff value by ≥4 of 6 assays.

RESULTS

Different anti-HBs assays were associated with statistically significant (P<0.05) differences in anti-HBs titres in all dilutions. Sensitivity and specificity ranged respectively from 64%-100% and 95%-100%. Agreement between assays around an anti-HBs titre cutoff value of 10IU/l ranged from 93%-100% and was 44% for a cutoff value of 100IU/l.

CONCLUSIONS

Around a cutoff value of 10IU/l use of the Access assay may result in false-negative results. Concerning the cutoff value of 100IU/l, a sample being classified below or above this cutoff relied heavily on the specific assay used, with both the Architect and the Access resulting in false-negative results.

Development of chronic hepatitis B infection in a hepatitis B vaccine responder

The Hepatitis B vaccine is highly effective for the prevention of hepatitis B (HBV) infection. We report the development of chronic HBV infection (Genotype F) in a vaccinated immunocompetent individual with an anti-HBsAb of 35 mIU/mL post completion of vaccine series. HBV vaccine is based on recombinant proteins of genotype-A and D (predominant genotypes in Europe). It may not be as effective for the prevention of more genetically diverse viruses such as genotype F (predominant genotype in Central and South America). Healthcare providers and patients should be aware that the HB vaccine does not confer 100% protection against HBV infection, even in the setting of protective antibody levels. Partners of individuals infected with non-A or -D genotypes should be advised to consider additional precautions to prevent transmission even in the setting protective antibody levels. Surveillance of circulating HBV genotypes should be undertaken to inform public health policy in relation to prevention of HB in high-risk groups such as men who have sex with men.

Suitable hepatitis B vaccine for adult immunization in China

The aim of this study was to evaluate, in adults, the immunogenicity of six hepatitis B vaccines with different doses or different manufacturers in the Chinese market and to provide evidence to support adult hepatitis B vaccination. Participants were randomly divided into six groups (I–VI). Six vaccines (4 at 10 μg/dose and 2 at 20 μg/dose) were administered intramuscularly to healthy adults at 0, 1 and 6 month intervals. All participants (16–50 years) who were negative for any hepatitis B virus serological markers were vaccinated. Anti-HBs levels were assessed 1 month and 1 year after the third vaccination. The anti-HBs seroconversion rate (anti-HBs >10mIU/ml) was 99.4 % (99.9 % for 10 μg dose groups and 97.9 % for 20 μg dose groups) 1 month after the third vaccination, and the anti-HBs seroreversion rate was 77.0 % (75.3 and 82.6 %) 1 year after the third vaccination (n = 1036). One month after completing the vaccinations, the seroconversion rates were not significantly different (100.0, 100.0, 99.6, 100.0 %) for the four 10 μg dose and two 20 μg dose groups (99.1, 96.9 %). One year after the third vaccination, the group II positive rate was significantly higher than the other three 10 μg dose groups, and the group VI positive rate was significantly higher than the other 20 μg dose group. Groups II and VI showed a significantly higher positive rate and anti-HBs geometric mean titer (GMT) than the other groups. The anti-HBs level declined with increasing age, and the seroreversion rate and GMT decreased over time. All six vaccines had high anti-HBs seroconversion rates and good immunization effects. The 10 μg dose vaccine (Dalian High-Tech) and the 20 μg dose vaccine (GlaxoSmithKline) are recommended for adults.

Minicircle HBV cccDNA with a Gaussia luciferase reporter for investigating HBV cccDNA biology and developing cccDNA-targeting drugs

Chronic Hepatitis B Virus (HBV) infection is generally not curable with current anti-viral drugs. Virus rebounds after stopping treatment from the stable HBV covalently-closed-circular DNA (cccDNA). The development of drugs that directly target cccDNA is hampered by the lack of robust HBV cccDNA models. We report here a novel HBV cccDNA technology that will meet the need. We engineered a minicircle HBV cccDNA with a Gaussia Luciferase reporter (mcHBV-GLuc cccDNA), which serves as a surrogate to measure cccDNA activity. The mcHBV-GLuc cccDNA was easily produced in bacteria, and it formed minichromosomes as HBV cccDNA episome DNA does when it was transfected into human hepatocytes. Compared to non-HBV minicircle plasmids, mcHBV-GLuc cccDNA showed persistent HBV-GLuc activity and HBx-dependent gene expression. Importantly, the mcHBV-GLuc cccDNA showed resistance to interferons (IFN) treatment, indicating its unique similarity to HBV cccDNA that is usually resistant to long-term IFN treatment in chronic HBV patients. Most importantly, GLuc illuminates cccDNA as a surrogate of cccDNA activity, providing a very sensitive and quick method to detect trace amount of cccDNA. The mcHBV-GLuc cccDNA model is independent of HBV infection, and will be valuable for investigating HBV cccDNA biology and for developing cccDNA-targeting drugs.

Response to anti-HBV vaccine and 10-year follow-up of antibody levels in healthcare workers

BACKGROUND

Despite improvements in public health and antiviral treatments, vaccination is still the most effective means of prevention of hepatitis B virus (HBV) infection. However, little is known about the duration of protection given by the anti-HBV vaccine. Healthcare workers represent a category at risk not only of contracting infection but also of being a source of contagion to patients.

OBJECTIVES

To assess individual responses to the anti-HBV vaccine and duration of protection 10 years after its administration in a cohort of healthcare workers employed by the University Hospital 'G. Martino' in Messina, Italy.

METHODS

One hundred and seventy medical staff who had been vaccinated following an incident carrying risk of HBV infection were included in this study. The group was followed over a 10-year period, and HBV antibody levels were assessed using an automated microparticle enzyme immunoassay.

RESULTS

Protective antibody levels (≥10 mIU/ml) were found in 65% of subjects who had completed the full vaccine schedule (three doses) and in 35% of subjects who had only received one or two doses of anti-HBV vaccine. Moreover, 10 years after vaccination, HBV antibody levels were inversely related to age at vaccination (P < 0.001). No differences were found between males and females.

CONCLUSIONS

This study, in line with the literature, shows the importance of completing the full vaccine schedule (three doses). Moreover, in order to have an effective and durable antibody response and avoid the risk of contracting HBV after an injury at work, it is important to recommend anti-HBV vaccination at a young age, ideally during childhood in accordance with the national vaccination policy.

Factors influencing immunologic response to hepatitis B vaccine in adults

Hepatitis B was still a worldwide health problem. This study aimed to conducted a systematic review and meta-analysis to assess a more precise estimation of factors that influence the response to hepatitis B vaccine in adults. Our included studies examined seroprotection rates close to the end of vaccination schedules in healthy adult populations. This meta-analysis including 21053 adults in 37 articles showed that a significantly decreased response to hepatitis B vaccine appeared in adults (age ≥ 40) (RR:1.86, 95% CI:1.55–2.23), male adults (RR:1.40, 95% CI:1.22–1.61), BMI ≥ 25 adults (RR:1.56, 95% CI:1.12–2.17), smoker (RR:1.53, 95% CI:1.21–1.93), and adults with concomitant disease (RR:1.39, 95% CI:1.04–1.86). Meanwhile, we further found a decreased response to hepatitis B vaccine appeared in adults (age ≥ 30) (RR:1.77, 95% CI:1.48–2.10), and adults (age ≥ 60) (RR:1.30, 95% CI:1.01–1.68). However, there were no difference in response to hepatitis B vaccine both in alcoholic (RR:0.90, 95% CI:0.64–1.26) and 0-1-12 vs. 0-1-6 vaccination schedule (RR:1.39, 95% CI:0.41–4.67). Pooling of these studies recommended the sooner the better for adult hepatitis B vaccine strategy. More vaccine doses, supplemental/additional strengthening immunity should be emphasized on the susceptible population of increasing aged, male, BMI ≥ 25, smoking and concomitant disease. The conventional 0-1-6 vaccination schedule could be still worth to be recommended.

Optimal vaccination program for healthy adults in China

There is still no suitable routine hepatitis B immunization strategy for adults in China. To establish an optimal vaccination schedule for healthy adults, we investigated various schedules in healthy adults. In this randomized 5143 healthy adults received 10 μg hepatitis B vaccine at 0, 1 and 3 months(group A), 0, 1 and 6 months(group B), or 0, 1 and 12 months(group C). Blood samples were collected after 1 month and 12 months after the third dose. The geometric mean titer (GMT), seroconversion rate (levels of anti-HBs ≥ 10 mIU/mL) and high response rate (levels of anti-HBs ≥ 100 mIU/mL) were assayed. In our study, 2438 healthy adults finished the full vaccination program and follow-up. The seroconversion/sero-protective rate of groups A-C at one and 12 month after administration of the third vaccine dose was 100%, 99.9% and 97.9% verse 64.9%, 75.7% and 79.0%, respectively. GMT for anti-HBs tested in group A to C within 1 or 12 month after the third vaccination was 213.16, 432.58 and 451.47 mIU/ml verse 22.07, 46.70 and 56.18 mIU/ml, respectively. There were significant differences of seroconversion/sero-protective rate and GMT among the 3 groups (p < 0.01). Given the high anti-HBs seroconversion rate and GMT in all 3 groups, a flexible schedule for Hepatitis B vaccine should be recommended to adults, but 0-1-12 schedule is a better choice.

Immune Responses to Single-Dose Versus Double-Dose Hepatitis B Vaccines in Healthcare Workers not Responding to the Primary Vaccine Series: A Randomized Clinical Trial

BACKGROUND

Recommendations to immunize healthcare workers (HCWs) against hepatitis B are well known. However, a proportion of individuals do not respond to the primary standard three-dose HB vaccination schedule.

OBJECTIVES

The current study aimed to evaluate whether a double-dose HB booster vaccine could induce better protective anti-HB titers than a single-dose booster in non-protected HCWs.

MATERIALS AND METHODS

This was a randomized clinical trial. A total of 91 HCWs not responding to the primary vaccine series in 2014 were enrolled. The participants were randomized into two groups that received a double dose of the HB vaccine containing 40 µg of antigen or a single dose of the HB vaccine containing 20 µg of antigen in three doses (at zero, one and six months after vaccination). Blood samples were collected before vaccinations and 28 days after the third dose to assess the seroconversion rate, according to the anti-HB antibody titer threshold of > 10 mIU/mL.

RESULTS

The seroconversion rates were 93.2% and 87.2% after the first booster doses of the double-dose and single-dose HB vaccines, respectively (P = 0.64). In the double-dose HB vaccine group, the seroconversion rate was 97.8% compared with 89.6% in the single-dose group following the second vaccine dose (P = 0.83). All of the participants in both groups were seroprotected after the third HB vaccine dose.

CONCLUSIONS

Both the single- and double-dose HB vaccines were adequately immunogenic, and the double-dose HB vaccine was not significantly more immunogenic than the single-dose vaccine in terms of the seroconversion rates of HCWs who had not responded to the primary vaccine series.

Hepatitis B and elders: An underestimated issue

As the world's population becomes older, the burden of hepatitis B virus in elderly has to be considered. The liver changes with aging and its function is eventually altered. The prevalence of hepatitis B virus is paradoxically more important in elderly in areas having vaccination programs, because of a loosening of the prevention in older patients. Some differences in hepatitis B presentation must be enhanced in elderly: lower spontaneous hepatitis B surface antigen clearance after a recent contamination, major risk of cirrhosis and hepatocarcinoma. Acute hepatitis B seems to be more often symptomatic, with a great risk of chronicity. Hepatocarcinoma linked to hepatitis B virus has a higher prevalence and a different presentation in elderly. Its treatment is the same as in younger people but is less often possible. Liver transplantation is contraindicated after 70 years old. Hepatitis B treatment panel is the same as in younger people (pegylated interferon, nucleoside or nucleotide agents). It gives identical results with no particular adverse events if the precautions for use are followed. Vaccination is less efficient, as in immunocompromised patients, and needs specific protocols.

Hepatitis B vaccination uptake and correlates of serologic response among HIV-infected and uninfected men who have sex with men (MSM) in Bangkok, Thailand

BACKGROUND

Vaccination against hepatitis B virus (HBV) is recommended for all HBV-susceptible men who have sex with men (MSM). There is limited information on correlates of immunity to HBV vaccination in this group. We present serologic response rates to hepatitis B vaccine and identify factors associated with impaired response among HIV-uninfected and HIV-infected Thai MSM.

METHODOLOGY

HBV-susceptible volunteers were offered hepatitis B vaccination at months zero, one, and six. We measured baseline (pre-vaccination) total serum IgG and IgG subclasses (all participants), baseline CD4 count, and plasma HIV-1 viral load (PVL) (HIV+ participants). HBV serologies were retested at 12 months. Serologic responses were compared between all groups in men receiving three vaccine doses.

RESULTS

511/651 HIV-negative and 64/84 HIV-positive participants completed the three-dose series. Response rates in HIV-uninfected and -infected participants were 90.1% vs. 50.0% (p<0.0001). Median pre-vaccination IgG was higher among non-responders than responders overall (1238.9.0 vs. 1057.0mg/dL, p=0.003) and among HIV-infected participants (1534.0 vs. 1244.5mg/dL, p=0.005), but not significantly among HIV-uninfected participants (1105.5 vs. 1054.3mg/dL, p=0.96). Pre-vaccination IgG1 and IgG3 levels were higher among HIV-positive than HIV-negative participants (median 866.0 vs. 520.3, and 105.8 vs. 83.1mg/dL, respectively, p<0.0001). Among HIV-infected participants, median CD4 count in non-responders was 378 cells/μL vs. 431 cells/μL in responders (p=0.20). Median PVL in non-responders was 64,800 copies/mL vs. 15500 copies/mL in responders (p=0.04). Participants with pre-vaccination plasma IgG >1550 mg/dL and PVL >10,000 copies/mL were almost always non-responsive (p<0.01).

CONCLUSIONS

HIV infection was associated with poor vaccine responses. High plasma viral load, elevated pre-vaccination total serum IgG and elevated pre-vaccination IgG1 are associated with poorer response to vaccination among HIV-infected MSM. In this group, the combination of high PVL and pre-vaccination total IgG is highly predictive of vaccine failure.

Immunogenicity of an investigational hepatitis B vaccine with a toll-like receptor 9 agonist adjuvant (HBsAg-1018) compared with a licensed hepatitis B vaccine in subpopulations of healthy adults 18-70 years of age

BACKGROUND

Immunologic response to a complete vaccine regimen of currently licensed alum-adjuvanted hepatitis B vaccines is reduced in several subpopulations, including older adults, men, obese persons, and smokers. Two phase 3 trials in healthy adults demonstrated that 2 doses over 1 month of an investigational hepatitis B vaccine (HBsAg-1018) induced superior seroprotection rates (SPRs) to 3 doses over 6 months of the licensed vaccine Engerix-B (HBsAg-Eng).

METHODS

An exploratory analysis of immunogenicity was conducted in subpopulations from pooled data for the 2 phase 3 trials.

RESULTS

In each subpopulation, the peak SPR in the HBsAg-1018 group was statistically significantly higher than the peak SPR in the HBsAg-Eng group. Peak HBsAg-1018 SPRs ranged from 91.6% to 99.7%, while peak HBsAg-Eng SPRs ranged from 67.7% to 92.9%.

CONCLUSION

In these exploratory analyses, 2 doses of HBsAg-1018 induced statistically significantly higher rates of seroprotection than 3 doses of HBsAg-Eng across all subpopulations.

Immunogenicity of hepatitis B vaccine in patients with inflammatory bowel disease and the benefits of revaccination

BACKGROUND AND AIM

The vaccination against hepatitis B virus (HBV) is recommended in patients with inflammatory bowel disease (IBD). However, the response to this vaccine seems to be lower in IBD patients than in the general population. This study aims to evaluate the immunogenicity of the HBV vaccine in a cohort of patients with IBD, to associate factors with the response and to analyze the effects of a second schedule vaccination.

METHODS

We conducted a retrospective cohort study of adults with IBD, susceptible to HBV infection. All patients received a three-dose standard schedule of HBV vaccine. Non-responders were revaccinated with a second three-dose standard schedule. Adequate immunity to HBV was defined as antibodies against hepatitis B surface antigen (anti-HBs) ≥ 10 mIU/mL. Age, comorbidities, treatment, and other variables were collected.

RESULTS

One hundred seventy-two patients were included and received the first HBV vaccine schedule. Eighty-seven developed anti-HBs ≥ 10 mIU/mL (50.6%; 95% confidence interval [CI]: 42.9-58.3). From the non-responders, 53 were revaccinated and 28 showed an adequate serological response (52.8%; 95% CI: 38.6-66.7). Age older than 55 years (OR: 3.6; 95% CI: 1.3-10.2) and comorbidities (OR: 2.8; 95% CI: 1.1-7.1) were associated with suboptimal response. In the multivariate analysis, only age was a predictor of non-response (age higher than 55 years; OR: 3.9; 95% CI: 1.3-11.9) CONCLUSION: The response rate to the HBV vaccine is lower in patients with IBD compared with the general population, especially in those older than 55 years. Revaccination improved response rate by 50%.

Old and new adjuvants for hepatitis B vaccines

The safety and immunogenicity profiles of currently available recombinant hepatitis B vaccines are excellent. However, it remains a real challenge to induce protective immunity in the target groups that respond poorly or not at all to conventional vaccines. Ideally, a hepatitis B vaccine can be developed that conveys lifelong protection against infection rapidly after the injection of a single dose. Although this goal is far from being reached, important improvements have been made. Novel vaccine adjuvants have been developed that enhance the immunogenicity of recombinant hepatitis B vaccines while maintaining a good safety profile. The different adjuvants and adjuvant systems that are discussed herein have all been thoroughly evaluated in clinical trials and some have reached or are close to reach the market.

Geographical variability in the likelihood of bloodstream infections due to gram-negative bacteria: correlation with proximity to the equator and health care expenditure

OBJECTIVE

Infections due to Gram-negative bacteria exhibit seasonal trends, with peak infection rates during warmer months. We hypothesized that the likelihood of a bloodstream infection due to Gram-negative bacteria increases with proximity to the equator. We tested this hypothesis and identified geographical, climatic and social factors associated with this variability.

DESIGN

We established a network of 23 international centers in 22 cities.

SETTING

De-identified results of positive blood cultures from 2007-2011 and data sources for geographic, climatic and socioeconomic factors were assembled for each center.

PARTICIPANTS

Patients at the 23 centers with positive blood cultures.

MAIN OUTCOME

Due to variability in the availability of total culture volumes across sites, our primary outcome measure was the fraction of positive blood cultures that yielded Gram-negative bacteria; sources of variability in this outcome measure were explored using meta-regression techniques.

RESULTS

The mean fraction of bacteremia associated with Gram-negative bacteria was 48.4% (range 26.4% to 61.8%). Although not all sites displayed significant seasonality, the overall P-value for seasonal oscillation was significant (P<0.001). In univariate meta-regression models, temperature, latitude, latitude squared, longitude, per capita gross domestic product and percent of gross domestic product spent on healthcare were all associated with the fraction of bacteremia due to Gram-negative bacteria. In multivariable models, only percent of gross domestic product spent on healthcare and distance from the equator (ie. latitude squared) were significantly associated with the fraction of bacteremia due to Gram-negative bacteria.

CONCLUSIONS

The likelihood of bacteremia due to Gram-negative bacteria varies markedly between cities, in a manner that appears to have both geographic (latitude) and socioeconomic (proportion gross domestic product devoted to health spending) determinants. Thus, the optimal approach to initial management of suspected bacteremia may be geographically specific. The rapid emergence of highly antibiotic-resistant Gram-negative pathogens may have geographically specific impacts.

Long-term immunogenicity and safety of the HPV-16/18 AS04-adjuvanted vaccine in 10- to 14-year-old girls: open 6-year follow-up of an initial observer-blinded, randomized trial

BACKGROUND

Immunogenicity and safety of the HPV-16/18 AS04-adjuvanted vaccine were evaluated up to 6 years postvaccination (month 72) in preteen/adolescent girls.

METHODS

Participants, who had received 3 HPV-16/18 AS04-adjuvanted vaccine doses at 10-14 years of age in an initial controlled, observer-blinded, randomized study (NCT00196924) and participated in the open 3-year follow-up (NCT00316706), were invited to continue the follow-up for up to 10 years postvaccination (NCT00877877). Anti-HPV-16 and -18 antibody titers were measured by enzyme-linked immunosorbent assays at yearly visits and were used to fit the modified power-law and piecewise models, predicting long-term immunogenicity. Serious adverse events (SAEs) and pregnancy information were recorded.

RESULTS

In the according-to-protocol immunogenicity cohort, all participants (N = 505) with data available remained seropositive for anti-HPV-16 and -18 antibodies at month 72. In initially seronegative participants, anti-HPV-16 and -18 antibody geometric mean titers were 65.8- and 33.0-fold higher than those associated with natural infection (NCT00122681) and 5.0- and 2.5-fold higher than those measured at month 69-74 in a study demonstrating vaccine efficacy in women aged 15-25 years (NCT00120848). Exploratory antibody modeling, based on the 6-year data, predicted that vaccine-induced population anti-HPV-16 and -18 antibody geometric mean titers would remain above those associated with natural infection for at least 20 years postvaccination. The HPV-16/18 AS04-adjuvanted vaccine safety profile was clinically acceptable.

CONCLUSIONS

In preteen/adolescent girls, the HPV-16/18 AS04-adjuvanted vaccine induced high anti-HPV-16 and -18 antibody levels up to 6 years postvaccination, which were predicted to remain above those induced by natural infection for at least 20 years.

New hepatitis B vaccine formulated with an improved adjuvant system

A new hepatitis B vaccine (FENDrix, GlaxoSmithKline Biologicals) containing as active substance 20 microg of recombinant hepatitis B virus surface antigen produced in Saccharomyces cerevisiae has recently been licensed in Europe. It is prepared with a novel adjuvant system: aluminum phosphate and 3-O-desacyl-4 -monophosphoryl lipid A. It is intended for use in adults from the age of 15 years onwards for active immunization against hepatitis B virus infection for patients with renal insufficiency (including prehemodialysis and hemodialysis patients). It is applied in a four-dose scheme: day 0, month 1, 2 and 6 after day 0. Due to the improved adjuvant system it induces higher antibody concentrations that reach protective levels in a faster fashion. Furthermore, due to higher titers reached after the primary immunization course, protective levels are retained for a longer period of time. Vaccination with FENDrix induces more transient local symptoms, with pain at the injection site being the most frequently reported solicited local symptom. Other symptoms such as fatigue, gastrointestinal disorders and headaches were also frequently observed but resolved without sequelae. The higher risk of hepatitis B transmission in patients with end-stage renal disease and the often immunocompromised status of these patients afford a tailored vaccination strategy that, up to now, has consisted of injecting double doses of ordinary hepatitis B vaccines. With the introduction of FENDrix there now exists an efficient alternative with superior immunogenicity that is, despite comparatively higher reactogenicity, well tolerated.

KLRG1 impairs CD4+ T cell responses via p16ink4a and p27kip1 pathways: role in hepatitis B vaccine failure in individuals with hepatitis C virus infection

Coinfection of hepatitis B virus (HBV) with hepatitis C virus (HCV) is quite common, leading to an increase in morbidity and mortality. As such, HBV vaccination is recommended in HCV-infected individuals. However, HBV vaccine responses in HCV-infected individuals are often blunted compared with uninfected populations. The mechanism for this failure of vaccine response in HCV-infected subjects remains unclear. In this study, we investigated the expression and function of an inhibitory receptor, killer cell lectin-like receptor subfamily G member 1 (KLRG1), in the regulation of CD4(+) T cells and HBV vaccine responses during HCV infection. We demonstrated that KLRG1 was overexpressed on CD4(+) T cells from HCV-infected, HBV vaccine nonresponders compared with HBV vaccine responders. The capacity of CD4(+) T cells to proliferate and secrete IL-2 cytokine was inversely associated with the level of KLRG1 expression. Importantly, blocking KLRG1 signaling resulted in a significant improvement in CD4(+) T cell proliferation and IL-2 production in HCV-infected, HBV vaccine nonresponders in response to TCR stimulation. Moreover, blockade of KLRG1 increased the phosphorylation of Akt (Ser(473)) and decreased the expression of cell cycle inhibitors p16(ink4a) and p27(kip1), which subsequently enhanced the expression of cyclin-dependent kinase 2 and cyclin E. These results suggest that the KLRG1 pathway impairs CD4(+) T cell responses to neoantigen and induces a state of immune senescence in individuals with HCV infection, raising the possibility that blocking this negative-signaling pathway might improve HBV vaccine responses in the setting of chronic viral infection.

Serologic Hepatitis B Virus Immunity in Health Care Workers

Health care workers (HCWs) are at high risk of blood borne infections including Hepatitis B virus (HBV) infection. HBV vaccination is recommended for HCWs but post vaccination testing of immune response (anti-HBs) is not routinely performed. In our study information on immune response after the first immunization schedule of HCWs is not available. By reason of the questions regarding long lasting immunity, we decided to assess the anti-HBs of HCWs who wished to check immune response after different times of vaccination and also unvaccinated persons in St. Marina University Hospital, Varna, Bulgaria. After informed consent, 341 HCWs were investigated. They were divided into 3 groups according to their status: Group A had no history of vaccination against HBV, Group B had no complete vaccination schedule and Group C had complete vaccination data. Of Group C, 32 had been vaccinated more than 10 years previously, 111 - 10–5 years previously and 48 - < 5 years previously. Quantitative detection of antibody to HBsAg (anti-HBs) by commercial ELISA was carried out. A total, positive immune response was detected in 35.6% (group A), 66.2% (group B) and 80.1% (group C) of HCWs investigated. Of Group C positive immune response was detected in 68.7%, 81.1% and 85.4% respectively of the time of vaccination. Detectable anti-HB was found in HCWs without HBV immunization, probably after unknown exposure to HBV. The lack of information regarding immune response after the first immunization schedule makes the interpretation of no detectible anti-HBs level 5–10 years post-immunization difficult. For the HCWs with anti-HBs loss, counseling for booster vaccine dose and consequent testing is mandatory.

High non-responsiveness of males and the elderly to standard hepatitis B vaccination among a large cohort of healthy employees

BACKGROUND

Hepatitis B virus infection is a major health problem. Although non-response is known to increase with age, hepatitis B vaccinations are considered to have only minor non-response rates (anti-HBs<10IU/L) in healthy subjects.

OBJECTIVES

The aim of this study was to quantify immunosenescence in a large retrospective cohort of 11,439 healthy adults who received HBV immunisation according to the standard vaccination regime.

STUDY DESIGN

We evaluated the response to the standard three-dose vaccination regimen, consisting of 20-μg doses of the HbsAg recombinant DNA hepatitis B vaccine, among 11,439 healthy employees using a retrospective cohort design. Logistic regression was applied to predict the non-response rate, and multivariate regression analysis was applied to predict antibody response. Predictors of responsiveness included sex, age and time between the last vaccination and antibody titre measurement.

RESULTS

From the age of 29 on in men and 43 on in women, more than 5% of subjects did not respond. Compared with women, men had a higher risk of non-response and exhibited a steeper decline in antibody titres produced with increasing age.

CONCLUSIONS

This retrospective cohort study demonstrates that immunosenescence starts at young age, especially among men, underlining the importance of vaccination at a young age to achieve long-lasting immunity. Moreover, HBV vaccination should always include testing for antibodies to facilitate the performance of necessary interventions to prevent long-term fatal complications.

Immune exhaustion and immune senescence: two distinct pathways for HBV vaccine failure during HCV and/or HIV infection

Given the shared risk factors for transmission, co-infection of hepatitis B virus (HBV) with hepatitis C virus (HCV) and/or human immunodeficiency virus (HIV) is quite common, and may lead to increases in morbidity and mortality. As such, HBV vaccine is recommended as the primary means to prevent HBV super-infection in HCV- and/or HIV-infected individuals. However, vaccine response (sero-conversion with a hepatitis B surface antibody titer >10 IU/L) in this setting is often blunted, with poor response rates to standard HBV vaccinations in virally infected individuals when compared with the healthy subjects. This phenomenon also occurs to other vaccines in adults, such as pneumococcal and influenza vaccines, in other immunocompromised hosts who are really at risk for opportunistic infections, such as individuals with hemodialysis, transplant, and malignancy. In this review, we summarize the underlying mechanisms involving vaccine failure in these conditions, focusing on immune exhaustion and immune senescence--two distinct signaling pathways regulating cell function and fate. We raise the possibility that blocking these negative signaling pathways might improve success rates of immunizations in the setting of chronic viral infection.

Immunogenicity and safety of an investigational hepatitis B vaccine with a Toll-like receptor 9 agonist adjuvant (HBsAg-1018) compared to a licensed hepatitis B vaccine in healthy adults 40-70 years of age

BACKGROUND

The currently licensed hepatitis B vaccines have limitations including hyporesponsiveness in older adults, poor compliance, and the extended time for most persons to develop seroprotection (e.g. >6months). A vaccine containing HBsAg combined with a Toll-like receptor 9 agonist adjuvant (HBsAg-1018) has been developed to overcome these limitations.

METHODS

A Phase 3, multicenter, randomized, subject- and observer-blinded, active-controlled trial was conducted among healthy subjects 40-70years of age comparing the immunogenicity and safety of two doses of HBsAg-1018 at 0 and 4weeks to three doses of licensed hepatitis B vaccine, HBsAg-Eng, at 0, 4, and 24weeks. The primary immunogenicity endpoint was noninferiority of the seroprotection rate (SPR; % with anti-HBs≥10mIU/mL) of HBsAg-1018 compared to the SPR of HBsAg-Eng at 8 weeks following the last dose of vaccine. Conditional upon meeting noninferiority, superiority of HBsAg-1018 over HBsAg-Eng was assessed. Safety was compared between the two vaccines.

RESULTS

At the primary endpoint, the SPR for the HBsAg-1018 group (90.0%) was superior to the SPR for the HBsAg-Eng group (70.5%) with an SPR difference of 19.5% (95% CI, 14.7%, 24.7%). At week 28 when the SPR peaked in the HBsAg-Eng group (72.8%), the SPR in the HBsAg-1018 group (94.8%) was significantly higher than in the HBsAg-Eng group. The SPR in the HBsAg-1018 group was significantly higher than in the HBsAg-Eng group at each study visit from week 4 through week 52. The safety profiles for the two vaccines were similar.

CONCLUSION

When compared to the HBsAg-Eng three-dose regimen given at 0, 1, and 6months, HBsAg-1018 demonstrated superior seroprotection with only two doses at 0 and 1month. The safety profile of HBsAg-1018 was comparable to that of the licensed vaccine, HBsAg-Eng. HBsAg-1018 would provide a significant public health contribution toward the prevention of hepatitis B infection.

Strategies to increase responsiveness to hepatitis B vaccination in adults with HIV-1

HIV and hepatitis B virus co-infection leads to substantially increased morbidity and mortality compared with either infection alone. Immunisation with hepatitis B virus vaccine is the most effective way to prevent the infection in people with HIV; however, these patients have decreased vaccine responses and a short duration of protection compared with immunocompetent individuals. Control of HIV replication with highly active antiretroviral therapy and increased CD4 cell counts are associated with improved immune responses to hepatitis B vaccination. New vaccination strategies, such as increased vaccine dose, use of the intradermal route, and addition of adjuvants, could improve response rates in adults with HIV.

Levamisole usage as an adjuvant to hepatitis B vaccine in hemodialysis patients, yes or no?

BACKGROUND

Hepatitis B virus (HBV) infection is much more common in hemodialysis patients than the general population. These patients have an impaired immune response to HBV vaccination; to that end there are certain studies that have evaluated levamisole as an immunomodulator agent improving HBV vaccination response rate in hemodialysis patients.

OBJECTIVES

In the current review, we have assembled all of the results to determine whether lavamisole is of value as an adjuvant to HBV vaccination in hemodialysis patients.

MATERIALS AND METHODS

Science Direct (Elsevier), ProQuest, Springer, MD Consult, BMJ Journals, Pubmed and Wiley were searched for levamisole application to HBV vaccination in hemodialysis patients. All studies revealed a seroconversion response level between levamisole plus HBV vaccine versus HBV vaccine alone.

RESULTS

From 10 relevant studies, 5 studies fulfilled our inclusion criteria. Three of them suggested the significant benefit of adding levamisole to the HBV vaccine to increase augment seroprotection level in hemodialysis patients. Another study reported a decrease in seroprotection level and another study showed no significant difference caused by levamisole administration.

CONCLUSIONS

Due to the limited number of studies evaluated, it is challenging to perform a definite decision about routinely administering levamisole in addition to the HBV vaccine for all hemodialysis patients. However, it does seem reasonable to recommend administration of levamisole for impaired immune response patients.

Intramuscular vs intradermal route for hepatitis B booster vaccine in celiac children

AIM: To compare intradermal (ID) and intramuscular (IM) booster doses, which have been used in healthy and high risk subjects, such as healthcare workers, haemodialysis patients, human immunodeficiency virus patients, and renal transplant recipients unresponsive to initial hepatitis B vaccination, in celiac individuals.

METHODS: We conducted our study on 58 celiac patients, vaccinated in the first year of life, whose blood analysis had showed the absence of protective hepatitis B virus (HBV) antibodies. All patients had received the last vaccine injection at least one year before study enrolment and they had been on a gluten free diet for at least 1 year. In all patients we randomly performed an HBV vaccine booster dose by ID or IM route. Thirty celiac patients were revaccinated with recombinant hepatitis B vaccine (Engerix B) 2 μg by the ID route, while 28 celiac patients were revaccinated with Engerix B 10 μg by the IM route. Four weeks after every booster dose, the anti-hepatitis B surface (HBs) antibody titer was measured by an enzyme-linked immune-adsorbent assay. We performed a maximum of three booster doses in patients with no anti-HBs antibodies after the first or the second vaccine dose. The cut off value for a negative anti-HBs antibody titer was 10 IU/L. Patients with values between 10 and 100 IU/L were considered "low responders" while patients with an antibody titer higher than 1000 IU/L were considered "high responders".

RESULTS: No significant difference in age, gender, duration of illness, and years of gluten intake was found between the two groups. We found a high percentage of "responders" after the first booster dose (ID = 76.7%, IM = 78.6%) and a greater increase after the third dose (ID = 90%, IM = 96.4%) of vaccine in both groups. Moreover we found a significantly higher number of high responders (with an anti-HBs antibody titer > 1000 IU/L) in the ID (40%) than in the IM (7.1%) group, and this difference was evident after the first booster dose of vaccination (P < 0.01). No side effects were recorded in performing delivery of the vaccine by either the ID or IM route.

CONCLUSION: Our study suggests that both ID and IM routes are effective and safe options to administer a booster dose of HBV vaccine in celiac patients. However the ID route seems to achieve a greater number of high responders and to have a better cost/benefit ratio.

Long-term persistence of seroprotection by hepatitis B vaccination in healthcare workers of southern Italy

BACKGROUND

The impact of hepatitis B virus (HBV) vaccination campaigns on HBV epidemiology needs to be evaluated, in order to assess the long-term immunity offered by vaccines against HBV.

OBJECTIVES

To evaluate the current status of anti-HBV vaccine coverage among healthcare workers (HCWs) in Southern Italy, and to determine the long-term persistence of antibodies to hepatitis B surface antigens (anti-HBs) in such a cohort of subjects.

PATIENTS AND METHODS

A longitudinal, retrospective seroepidemiological survey was conducted among 451 HCWs, who were working at or visiting, the Occupational Health Department of a city hospital, in Catania, Italy, between January 1976 and December 2010.

RESULTS

At the 30-year follow-up (mean follow-up 10.15 ± 5.96 years, range 0.74-30), 261 HCWs had detectable anti-HBs titers indicating a persistence of seroprotection of 89.4% (out of 292 anti-HBs positive results, three months after vaccination). An inadequate vaccination schedule was the strongest predictor of antibody loss during follow-up (OR = 8.37 95% CI: 5.41-12.95, P < 0.001). A Kaplan-Maier survival curve revealed that the persistence of anti-HBs 30 years after vaccination, was 92.2% for high responders, while it was only 27.3% for low responders (P = 0.001).

CONCLUSIONS

A good level of seroprotection persisted in 57.9% of the subjects after 30 years. Factors related to this immunization status confirmed the importance of vaccinating HCWs early in their careers and ensuring an adequate vaccination schedule. However, with particular reference to the low rate of hepatitis B vaccine coverage among HCWs in Southern Italy, the implementation of a new educational intervention as part of an active vaccination program is needed.

Vaccines for the elderly

Vaccination is the most efficient strategy to prevent infectious disease. The increased vulnerability to infection of the elderly makes them a particularly important target population for vaccination. However, most vaccines are less immunogenic and efficient in the elderly because of age-related changes in the immune system. Vaccination against influenza, Streptococcus pneumoniae and varicella zoster virus is recommended for the elderly in many countries. Various strategies such as the use of adjuvants and novel administration routes are pursued to improve influenza vaccination for the elderly and recent developments in the field of pneumococcal vaccination led to the licensure of protein-conjugated polysaccharide vaccines containing up to 13 serotypes. As antibody titres are generally lower in the elderly and-particularly for inactivated vaccines-decline fast in the elderly, regular booster immunizations, for example against tetanus, diphtheria and, in endemic areas, tick-borne encephalitis, are essential during adulthood to ensure protection of the elderly. With increasing health and travel opportunities in old age the importance of travel vaccines for persons over the age of 60 is growing. However, little is known about immunogenicity and efficacy of travel vaccines in this age group. Despite major advances in the field of vaccinology over the last decades, there are still possibilities for improvement concerning vaccines for the elderly. Novel approaches, such as viral vectors for antigen delivery, DNA-based vaccines and innovative adjuvants, particularly toll-like receptor agonists, will help to achieve optimal protection against infectious diseases in old age.

Balancing the Efficacy and Safety of Vaccines in the Elderly

With advances in global health care, ageing populations are expected to grow worldwide throughout the 21^st century. Increased lifespan is a testament to modern medical and social practices, but also presents a growing challenge to a system with limited resources. Elderly populations present specific concerns related to preventative health practices, especially vaccination. Although the power of vaccination is unquestionable in controlling infectious disease, immunosenescence can lead to reduced immune responses following immunization in the elderly, and increased morbidity and mortality. Further complicating this issue, some vaccines themselves may pose a substantial safety risk in the elderly when compared to younger counterparts. Though any health care intervention must balance risk and reward, safety and immunogenicity are often poorly characterized in older populations. This review explores several domestic and travel vaccines, examining what is known concerning efficacy and safety in the elderly, and considers future alternatives.

Quality control measures for lowering the seroconversion rate of hemodialysis patients with hepatitis B or C virus

BACKGROUND

Hemodialysis (HD) patients are at high risk of infection by hepatitis B virus (HBV) or hepatitis C virus (HCV). The present study was designed to determine the impact of quality control measures on the prevention of transmission of blood-borne viruses.

METHODS

A total of 6182 adult maintenance HD patients from all HD units in Zhejiang Province were recruited on January 1, 2007. The baseline demographic and clinical characteristics were recorded and all patients were followed up until death or survival at 4 years later. The Quality Control Standards of Hemodialysis were gradually implemented in HD units. The HBV or HCV seroconversion rates of the recruited patients were calculated and compared every year during the observation period.

RESULTS

The prevalence of HBV was 8.3% at the beginning of the study, and 6.6% for HCV. With the implementation of the HD quality control measures, the HBV seroconversion rate tended to decrease year by year (X2=6.620, P=0.085), and the HCV seroconversion rate decreased significantly (X2=10.41, P=0.015). Compared with the data in 2007, the HBV seroconversion rate (X2=4.204, P=0.040, relative risk ratio 0.393, 95% CI 0.156-0.991) and the HCV seroconversion rate (X2=7.373, P=0.007, relative risk ratio 0.386, 95% CI 0.189-0.787) decreased significantly in 2010.

CONCLUSION

Quality control measures for HD decreased the seroconversion rates of HBV or HCV in HD patients, showing that updated quality control measures reduce the risk for transmission of blood-borne viruses in the HD population.

Demonstration of safety and enhanced seroprotection against hepatitis B with investigational HBsAg-1018 ISS vaccine compared to a licensed hepatitis B vaccine

Adults 40 years of age and older have been shown to be hypo-responsive immunologically to the currently available hepatitis B virus (HBV) vaccines. Three intramuscular doses of a Toll-like receptor 9 agonist, 1018 immunostimulatory sequence (1018 ISS) adjuvant, combined with recombinant hepatitis B surface antigen (HBsAg) demonstrated faster, superior, and more durable seroprotection than three doses of a licensed comparator HBV vaccine (Engerix-B(®)). This investigational vaccine, HBsAg-1018 ISS, was well tolerated with a safety profile similar to the comparator vaccine. These results suggest that HBsAg-1018 may be more effective in this hypo-responsive population.

Persistence of Protective Hepatitis B Surface Antibody Titers after Successful Double-Dose Hepatitis B Virus Rescue Vaccination in HIV-Infected Patients

Background/Aims

To assess the durability of protective hepatitis B surface antibody (anti-HBs) titers in HIV-infected patients who responded to double-dose hepatitis B virus (HBV) rescue vaccination.

Methods

A retrospective chart review was performed for HIV-infected patients who received the double-dose HBV rescue vaccination at 0-, 1-, and 2-month intervals after they had failed conventional HBV vaccination series. A protective antibody response was defined as an anti-HBs titer ≥10 mIU/mL.

Results

Of 54 HIV-infected patients who received a double-dose HBV rescue vaccination, 44 patients (81.5%) had a positive response and achieved protective anti-HB titers. Of the 44 patients who developed protective anti-HB titers, 33 patients received an evaluation of their anti-HB titers 12 months later. Of the 33 patients, 19 (57.6%) had persistent protective anti-HB titers (persistent responders, PR), and 14 patients (42.4%) lost their protective anti-HB titers (nonpersistent responders, NPR). There were significantly more patients who had an undetectable HIV viral load (<50 copies/mL) at baseline and follow-up in the PR group (11/19, 57.9%) than in the NPR group (3/14, 21.4%, p=0.036). Logistic regression analysis showed that an undetectable HIV viral load at baseline and follow-up (odds ratio, 12.973; 95% confidence interval, 1.189 to 141.515; p=0.036) was associated with PR.

Conclusions

Protective anti-HB titers may decrease over time after successful double-dose HBV rescue vaccination in HIV-infected patients. HIV viral load suppression could improve the persistence of anti-HB titers.

Effect of age and frequency of injections on immune response to hepatitis B vaccination in drug users

Despite the high immunogenicity of the hepatitis B vaccine, evidence suggests that immunological response in drug users is impaired compared to the general population. A sample of not-in-treatment adult drug users from two communities in Houston, TX, USA, susceptible to hepatitis B virus (HBV), was sampled via outreach workers and referral methodology. Participants were randomized to either the standard multi-dose hepatitis B vaccine schedule (0, 1, and 6 months) or to an accelerated (0, 1, and 2 months) schedule. The participants were followed for 1 year. Antibody levels were measured at 2, 6 and 12 months after enrollment in order to determine the immune responses. At 12 months, cumulative adequate protective response was achieved in 65% of the HBV susceptible subgroup using both the standard and accelerated schedules. The standard group had a higher mean antibody titer (184.6 mIU/mL vs 57.6 mIU/mL). But at 6 months, seroconversion at the adequate protective response was reached by a higher proportion of participants and the mean antibody titer was also higher in the accelerated schedule group (104.8 mIU/mL vs. 64.3 mIU/mL). Multivariate analyses indicated a 63% increased risk of non-response for participants 40 years or older (p=0.046). Injecting drugs more than once a day was also highly associated with the risk of non-response (p=0.016). Conclusions from this research will guide the development of future vaccination programs that anticipate other prevalent chronic conditions, susceptibilities, and risk-taking behaviors of hard-to-reach populations.

Evaluation of hepatitis B vaccine immunogenicity among older adults during an outbreak response in assisted living facilities

BACKGROUND

During the past decade, in the United States, an increasing number of hepatitis B outbreaks have been reported in assisted living facilities (ALFs) as a result of breaches in infection control practices. We evaluated the seroprotection rates conferred by hepatitis B vaccine among older adults during a response to an outbreak that occurred in multiple ALFs and assessed the influence of demographic and clinical factors on vaccine response.

METHODS

Residents were screened for hepatitis B and C infection prior to vaccination and susceptible residents were vaccinated against hepatitis B with one dose of 20 μg Engerix-B™ (GSK) given at 0, 1, and 4 months. Blood samples were collected 80-90 days after the third vaccine dose to test for anti-HBs levels.

RESULTS

Of the 48 residents who had post-vaccination blood specimens collected after the third vaccine dose, 16 (33.3%) achieved anti-HBs concentration ≥10 mIU/mL. Age was a significant determinant of seroprotection with rates decreasing from 88% among persons aged ≤60 years to 12% among persons aged ≥90 years (p=0.001). Geometric mean concentrations were higher among non-diabetic than diabetic residents, however, the difference was not statistically significant (5.1 vs. 3.8 mIU/mL, p=0.7).

CONCLUSIONS

These findings highlight that hepatitis B vaccination is of limited effectiveness when administered to older adults. Improvements in infection control and vaccination at earlier ages might be necessary to prevent spread of infection in ALFs.

Persistence of immune response to HPV-16/18 AS04-adjuvanted cervical cancer vaccine in women aged 15-55 years

The HPV-16/18 AS04-adjuvanted vaccine (Cervarix®, GlaxoSmithKline Biologicals) has been shown to induce a robust immune response in women aged 15-55 years (103514/NCT00196937). This follow-up study is the first report of persistence of immune response and safety profile through 48 months after vaccination in women aged 15-55 years. In this open-label, age-stratified Phase III study in Germany and Poland (105882/NCT00196937), healthy women aged 15-55 years received 3 doses of HPV-16/18 AS04-adjuvanted vaccine at 0, 1, and 6 months. Anti-HPV-16/18 seropositivity rates and geometric mean antibody titers (GMTs) were assessed by enzyme-linked immunosorbent assay (ELISA) in women aged 15-25 (n=168), 26-45 (n=186) and 46-55 years (n=177) from the time of first vaccination through 48 months. At Month 48, all subjects were seropositive for anti-HPV-16 antibodies and 99.4% were seropositive for anti-HPV-18. Antibody kinetics were as previously reported, with peak response at Month 7 followed by a gradual decline tending towards a plateau in all age groups. Anti-HPV-16/18 GMTs were sustained at Month 48 in all age groups, including women aged 46-55 years in whom GMTs were respectively 11-fold and 5-fold higher than natural infection levels. The vaccine exhibited a clinically acceptable safety profile in all age groups. In summary, the HPV-16/18 AS04-adjuvanted vaccine induces high and sustained immune responses in women aged 15-55 years, with antibody levels remaining several-fold higher than natural infection levels for at least 4 years after the first vaccine dose.

Co-administration of human papillomavirus-16/18 AS04-adjuvanted vaccine with hepatitis B vaccine: randomized study in healthy girls

BACKGROUND

To evaluate co-administration of GlaxoSmithKline Biologicals' human papillomavirus-16/18 AS04-adjuvanted vaccine (HPV) and hepatitis B vaccine (HepB).

METHODS

This was a randomized, controlled, open, multicenter study. Healthy girls, aged 9-15 years, were randomized to receive HPV (n=247), HepB (n=247) or HPV co-administered with HepB (HPV+HepB; n=247) at Months 0, 1 and 6. Antibodies against hepatitis B surface antigen (HBs), HPV-16 and HPV-18 were measured, and reactogenicity and safety monitored. Co-primary objectives were to demonstrate non-inferiority of hepatitis B and HPV-16/18 immune responses at Month 7 for co-administered vaccines, compared with vaccines administered alone, in the according-to-protocol cohort.

RESULTS

The pre-defined criteria for non-inferiority were met for all co-primary immunogenicity endpoints at Month 7. Anti-HBs seroprotection rates ≥10mIU/mL were achieved by 97.9% and 100% of girls, respectively, following co-administration or HepB alone. Anti-HBs geometric mean titers (GMTs) (95% confidence interval) were 1280.9 (973.3-1685.7) and 3107.7 (2473.1-3905.1) milli-international units/mL, respectively. Anti-HPV-16 and -18 seroconversion rates were achieved by ≥99% of girls following co-administration or HPV alone. Anti-HPV-16 GMTs were 19819.8 (16856.9-23303.6) and 21712.6 (19460.2-24225.6) ELISA units (ELU)/mL, respectively. Anti-HPV-18 GMTs were 8835.1 (7636.3-10222.1) and 8838.6 (7948.5-9828.4) ELU/mL, respectively. Co-administration was generally well tolerated.

CONCLUSIONS

The study results support the co-administration of HPV-16/18 AS04-adjuvanted vaccine with hepatitis B vaccine in adolescent girls aged 9-15 years.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov registration number NCT00652938.

Surface antibody and cytokine response to recombinant Chinese hamster ovary cell (CHO) hepatitis B vaccine

OBJECTIVE

To compare the immune responses of the 10 μg and 20 μg doses of CHO hepatitis B vaccine on adults.

METHODS

Adults aged 18-45 years who gave a history of never having received hepatitis B vaccine and lacked serologic evidence of infection to hepatitis B virus (HBV) infection or previous vaccination were enrolled into the study. A total of 642 eligible participants were randomized to receive 3 doses of either the 10 μg or the 20 μg formulation of CHO hepatitis B vaccine in a 0-1-6 month schedule. Each study subject had a serologic specimen collected one month following the third vaccine dose that was tested for markers of HBV infection and anti-HBs by Abbott I2000. Persons who tested negative for anti-HBs negative persons were tested for HBV DNA. Logistic regression was used to identify factors associated with antibody response. Among the participants, 153 subjects had their lymphocytes cultivated and tested for cytokine production. Enzyme-linked immunospot (ELISPOT) was used to test spot numbers of IL-4, IFN-γ which produced by lymphocyte.

RESULTS

The anti-HBs seroconversion rate was 88.8% (95% CI: 85.4-92.2%) and 95.3% (95% CI: 93.0-97.6%), respectively in 10 μg and 20 μg group. Geometric mean titers (GMT) were 173.42 mIU/ml and 585.51 mIU/ml, respectively in 10 μg and 20 μg groups. Multivariate analysis demonstrated that diabetes, spouse is hepatitis B virus infector, older age and receipt of the 10 μg dose were all negatively associated with antibody response (P<.05). Cellular immunity results showed: IL-4 immunity spot numbers in 20 μg group was higher than 10 μg group. With anti-HBs increased, the IL-4 immunity spot numbers increased significantly which had significant positive correlation (Spearman coefficient=0.538, P<0.0001). IFN-γ spot numbers had no statistical significant between the two groups.

CONCLUSION

The humoral immunity and cytokines response among the group that received the 20 μg CHO hepatitis B vaccine dose was superior compared to the group that received the 10 μg dose. The 20 μg dose of CHO hepatitis B vaccine should be prioritized for adult vaccination programs in China.

Cellular immunosenescence in adult male crickets, Gryllus assimilis

Ecological immunity studies in invertebrates, particularly insects, have generated new insights into trade-offs between immune functions and other physiological parameters. These studies document physiologically directed reallocations of immune costs to other high-cost areas of physiology. Immunosenescence, recognized as the age-related deterioration of immune functions, is another mechanism of radically altering immune systems. We investigated the hypothesis that aging brings on immunosenescence in adult males of the cricket, Gryllus assimilis. Our data show that the intensity of melanotic nodule formation decreased with adult age from after 3-week post-adult emergence. Circulating hemocyte populations similarly decreased from about 5,000 hemocytes/µl hemolymph to about 1,000 hemocytes/µl hemolymph. The numbers of damaged hemocytes in circulation increased from less than 10% at 1-week post-adult emergence to approximately 60% by 3-week post-adult emergence. The composition of hemocyte types changed with age, with increasing proportions of granulocytes and decreasing proportions of plasmatocytes. The declines in nodule formation were not linked to the adult age of sexual behaviors, which begin shortly after entering adulthood in this species. We infer that age-related senescence, rather than cost reallocations, may account for observed declines in various parameters of immune functions in insects, as seen in other animals.