Immunogenicity of combined hepatitis A and B vaccine in elderly persons

Immunosenescence and inflamm-ageing in COVID-19

The destructive effects of coronavirus disease 2019 (COVID-19) on the elderly and people with cardiovascular disease have been proven. New findings shed light on the role of aging pathways on life span and health age. New therapies that focus on aging-related pathways may positively impact the treatment of this acute respiratory infection. Using new therapies that boost the level of the immune system can support the elderly with co-morbidities against the acute form of COVID-19. This article discusses the effect of the aging immune system against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the pathways affecting this severity of infection.

Analysis of the effect of cytomegalovirus infection in clinical outcomes and prolonged duration of SARS-CoV-2 shedding in intensive care unit patients with COVID-19 pneumonia

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a global outbreak disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Cytomegalovirus (CMV) infection can occur in critical COVID-19 patients and is associated with adverse clinical outcomes.

OBJECTIVE

The aim of this study was to explore the clinical characteristics and outcome of CMV infection in critical COVID-19 patients.

DESIGN

This was a retrospective cohort study.

METHODS

From May to September 2021, SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR)-confirmed COVID-19 patients with intensive care unit (ICU) admission were enrolled. CMV infection was confirmed by PCR. Baseline characteristics, critical illness data and clinical outcomes were recorded and analyzed.

RESULTS

Seventy-two RT-PCR-confirmed COVID-19 patients with ICU admission were included during the study period and 48 (66.7%) patients required mechanical ventilation (MV). Overall, in-hospital mortality was 19.4%. Twenty-one (29.2%) patients developed CMV infection. Patients with CMV infection had a higher likelihood of diabetes, higher lactate dehydrogenase and lactate levels, and higher proportions of MV, anticoagulant, and steroid use. Patients with CMV infection were associated with longer duration of SARS-CoV-2 shedding, longer ICU and hospital stay, and fewer ventilator-free days. The independent risk factor for development of CMV infection was a higher accumulative steroid dose.

CONCLUSION

CMV infection adversely impacted the outcomes of critical COVID-19 patients, resulting in longer ICU stays, longer mechanical ventilation uses and prolonged shedding of SARS-CoV-2.

How to Effectively Monitor Aging Patients with Chronic Hepatitis B: A Review

Hepatitis B virus (HBV) infection is a major global public health challenge associated with significant morbidity and mortality. Due to worldwide population aging, HBV infection in the elderly will become increasingly prevalent. Effective universal vaccination programs exist but these are largely targeted towards the younger population. Therefore, the elderly population remains at risk of higher disease burden. New diagnoses of HBV infection in the elderly are usually asymptomatic chronic infections which increases their risk of developing cirrhosis, hepatocellular carcinoma, and liver disease-related mortality, especially if left untreated. Physiological changes and the increasing prevalence of multimorbidity associated with aging also potentially worsen outcomes in elderly patients with chronic HBV infection. Therefore, this cohort of patients should be monitored closely and effectively. Current international clinical practice guidelines unfortunately do not provide hard treatment endpoints specific to elderly patients with chronic HBV infection. Management of these patients is complex and requires an individualized approach. Multiple factors such as physiological changes, comorbidities, compliance, treatment tolerability and efficacy, burden of treatment, and realistic treatment goals need to be considered. Shared decision-making between patient and clinician is essential to ensure that the final decision for or against treatment aligns with the patient's values and preferences. This review article aims to summarize the monitoring and management of chronic HBV infection in the aging population.

Safety, tolerability, and immunogenicity of a SARS-CoV-2 recombinant spike RBD protein vaccine: A randomised, double-blind, placebo-controlled, phase 1-2 clinical trial (ABDALA Study)

BACKGROUND

Multiple vaccine candidates against COVID-19 are currently being evaluated. We evaluate the safety and immunogenicity protein of a novel SARS-CoV-2 virus receptor-binding domain (RBD) vaccine.

METHODS

A phase 1-2, randomised, double-blind, placebo-controlled trial was carried out in "Saturnino Lora" Hospital, Santiago de Cuba, Cuba. Subjects (healthy or those with controlled chronic diseases) aged between 19 and 80 years, who gave written informed consent were eligible. Subjects were randomly assigned (1:1:1, in blocks) to three groups: placebo, 25 µg and 50 µg RBD vaccine (Abdala). The product was administered intramuscularly, 0·5 mL in the deltoid region. During the first phase, two immunization schedules were studied: 0-14-28 days (short) and 0-28-56 days (long). In phase 2, only the short schedule was evaluated. The organoleptic characteristics and presentations of vaccine and placebo were identical. All participants (subjects, clinical researchers, statisticians, laboratory technicians, and monitors) remained masked during the study period. The main endpoints were safety and the proportion of subjects with seroconversion of anti-RBD IgG antibodies, analysed by intention to treat and per protocol, respectively. The trial is registered with the Cuban Public Registry of Clinical Trials, RPCEC00000346.

FINDINGS

Between Dec 7, 2020, and Feb 9, 2021, 792 subjects were included; 132 (66 in each vaccination schedule, divided into 22 for each group) in phase 1, and 660 (220 in each group plus 66 from the short scheme of phase 1) in phase 2. The product was well tolerated. No severe adverse events were reported. During phase 1, the incidence of adverse events in the 25 µg, 50 µg, and placebo arms for the short schedule were 6/22 (27·3%), 6/22 (27·3%), 3/22 (13·6%), respectively, and for the long schedule were 8/22 (36·4%), 9/22 (40·9%), 4/22 (18·2%), respectively. In phase 2, adverse reactions were reported by 53/242 (21·9%), 75/242 (31·0%) and 41/242 (16·9%) participants in the 25 µg, 50 µg, and placebo group, respectively. Adverse reactions were minimal, mostly mild, and from the injection site, which resolved in the first 24-48 hours. In phase 1, seroconversion at day 56 was seen in 95·2% of the participants (20/21) in the 50 μg group, 81% (17/21) in the 25 μg group, and none in the placebo group (0/22). For the long schedule, seroconversion at day 70 was seen in 100% of the participants (21/21) in the 50 μg group, 94·7% (18/19) in the 25 μg group, and none in the placebo group (0/22). In phase 2, seroconversion of anti-RBD IgG antibodies at day 56 was seen in 89·2% of the participants in the 50 μg group (214/240; 95% CI 84·5-92·82), 77·7% in the 25 μg group (185/238; 72·0-82·9) and 4·6% in the placebo group (11/239; 2·3-8·1). Compared with the placebo arm, the differences in the proportion of participants with seroconversion were 73·1% (95% CI 66·8-79·5) and 84·6% (79·4-89·7) in the 25 μg and 50 μg groups, respectively. The seroconversion rate in the 50 μg group was significantly higher than in the 25 μg group (p=0·0012).

INTERPRETATION

The Abdala vaccine was safe, well tolerated, and induced humoral immune responses against SARS-CoV-2. These results, in the context of the emergency COVID-19 pandemic, support the 50 μg dose, applied in a 0-14-28 days schedule, for further clinical trials to confirm vaccine efficacy.

FUNDING

Centre for Genetic Engineering and Biotechnology (CIGB), Havana, Cuba.

Vaccination of older adults: Influenza, pneumococcal disease, herpes zoster, COVID-19 and beyond

Preserving good health in old age is of utmost importance to alleviate societal, economic and health care-related challenges caused by an aging society. The prevalence and severity of many infectious diseases is higher in older adults, and in addition to the acute disease, long-term sequelae, such as exacerbation of underlying chronic disease, onset of frailty or increased long-term care dependency, are frequent. Prevention of infections e.g. by vaccination is therefore an important measure to ensure healthy aging and preserve quality of life. Several vaccines are specifically recommended for older adults in many countries, and in the current SARS-CoV-2 pandemic older adults were among the first target groups for vaccination due to their high risk for severe disease. This review highlights clinical data on the influenza, Streptococcus pneumoniae and herpes zoster vaccines, summarizes recent developments to improve vaccine efficacy, such as the use of adjuvants or higher antigen dose for influenza, and gives an overview of SARS-CoV-2 vaccine development for older adults. Substantial research is ongoing to further improve vaccines, e.g. by developing universal influenza and pneumococcal vaccines to overcome the limitations of the current strain-specific vaccines, and to develop novel vaccines against pathogens, which cause considerable morbidity and mortality in older adults, but for which no vaccines are currently available. In addition, we need to improve uptake of the existing vaccines and increase awareness for life-long vaccination in order to provide optimal protection for the vulnerable older age group.

Implications of Inflammatory States on Dysfunctional Immune Responses in Aging and Obesity

Aging and obesity are two conditions characterized by chronic, low-grade inflammation. While both conditions are also associated with dysfunctional immune responses, the shared and distinct underlying mechanisms are just starting to be uncovered. In fact, recent findings have suggested that the effects of obesity on the immune system can be thought of as a state of accelerated aging. Here we propose that chronic, low-grade inflammation seen in obesity and aging is complex, affects multiple cell types, and results in an altered basal immune state. In aging, part of this altered state is the emergence of regulatory immune populations that lead to further immune dysfunction in an attempt to reduce chronic inflammation. While in obesity, part of the altered state is the effect of expanding adipose tissue on immune cell function. Thus, in this review, we compare, and contrast altered immune states in aging and obesity and discuss their potential contribution to a shared clinical problem- decreased vaccine responsiveness.

SARS-CoV-2, COVID-19 and the Ageing Immune System

The coronavirus disease 2019 (COVID-19) pandemic is a global health threat with particular risk for severe disease and death in older adults and in adults with age-related metabolic and cardiovascular disease. Recent advances in the science of ageing have highlighted how ageing pathways control not only lifespan but also healthspan, the healthy years of life. Here, we discuss the ageing immune system and its ability to respond to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We specifically focus on the intersect of severe COVID-19 and immunosenescence to highlight pathways that may be determinant for the risk of complications and death following infection with SARS-CoV-2. New or adapted therapeutics that target ageing-associated pathways may be important tools to reduce the burden of death and long-term disability caused by this pandemic. Proposed interventions aimed at immunosenescence could enhance immune function not only in the elderly but in susceptible younger individuals as well, ultimately improving complications of severe COVID-19 for all ages.

Vaccine responses in ageing and chronic viral infection

Over the last few decades, changing population demographics have shown that there are a growing number of individuals living past the age of 60. With this expanding older population comes an increase in individuals that are more susceptible to chronic illness and disease. An important part of maintaining health in this population is through prophylactic vaccination, however, there is growing evidence that vaccines may be less effective in the elderly. Furthermore, with the success of anti-viral therapies, chronic infections such as HIV are becoming increasingly prevalent in older populations and present a relatively unstudied population with respect to the efficacy of vaccination. Here we will examine the evidence for age-associated reduction in antibody and cellular responsiveness to a variety of common vaccines and investigate the underlying causes attributed to this phenomenon, such as inflammation and senescence. We will also discuss the impact of chronic viral infections on immune responses in both young and elderly patients, particularly those living with HIV, and how this affects vaccinations in these populations.

Immunesenescence: A Predisposing Risk Factor for the Development of COVID-19?

Bearing a strong resemblance to the phenotypic and functional remodeling of the immune system that occurs during aging (termed immunesenescence), the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of Coronavirus disease 2019 (COVID-19), is characterized by an expansion of inflammatory monocytes, functional exhaustion of lymphocytes, dysregulated myeloid responses and the presence of highly activated senescent T cells. Alongside advanced age, male gender and pre-existing co-morbidities [e.g., obesity and type 2 diabetes (T2D)] are emerging as significant risk factors for COVID-19. Interestingly, immunesenescence is more profound in males when compared to females, whilst accelerated aging of the immune system, termed premature immunesenescence, has been described in obese subjects and T2D patients. Thus, as three distinct demographic groups with an increased susceptibility to COVID-19 share a common immune profile, could immunesenescence be a generic contributory factor in the development of severe COVID-19? Here, by focussing on three key aspects of an immune response, namely pathogen recognition, elimination and resolution, we address this question by discussing how immunesenescence may weaken or exacerbate the immune response to SARS-CoV-2. We also highlight how aspects of immunesenescence could render potential COVID-19 treatments less effective in older adults and draw attention to certain therapeutic options, which by reversing or circumventing certain features of immunesenescence may prove to be beneficial for the treatment of groups at high risk of severe COVID-19.

The SENIEUR protocol and the efficacy of hepatitis B vaccination in healthy elderly persons by age, gender, and vaccine route

BACKGROUND

Reduced response to hepatitis B vaccines is associated with aging, confounding and comorbid conditions, as well as inadvertent subcutaneous (SC) inoculation. We hypothesized that the antibody and T cell-mediated immune responses (T-CMI) of elderly adults to a vaccine intended for intramuscular (IM) administration would be attenuated when deposited into SC fat, independent of confounding conditions.

RESULTS

Fifty-two healthy, community dwelling elderly adults (65-82 years), seronegative for HBV, were enrolled in the SENIEUR protocol as a strictly healthy population. These seniors were randomized to receive a licensed alum-adjuvanted recombinant HBV vaccine either SC or IM, with the inoculum site verified by imaging. The response rates, defined as hepatitis B surface antibodies (HBsAb) ≥10 IU/L, were significantly lower in the elderly than in young adults, a group of 12, healthy, 21-34-year-old volunteers. Moreover, elderly participants who received the vaccine IM were significantly more likely to be responders than those immunized SC (54% versus 16%, p = 0.008). The low seroconversion rate in the IM group progressively declined with increasing age, and responders had significantly lower HBsAb titers and limited isotype responses. Moreover, T-CMI (proliferation and cytokine production) were significantly reduced in both percentage of responders and intensity of the response for both Th1 and Th2 subsets in the elderly.

CONCLUSIONS

Our data demonstrate the blunted immunogenicity of SC inoculation as measured by peak titers and response rates. Further, the qualitative and quantitative deficits in B- and T-CMI responses to primary alum adjuvanted protein antigens persisted even in strictly healthy elderly populations with verified IM placement compared to younger populations.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT04162223. Registered 14 November 2019. Retrospectively registered.

Hepatitis B Virus (HBV) Subviral Particles as Protective Vaccines and Vaccine Platforms

Hepatitis B remains one of the major global health problems more than 40 years after the identification of human hepatitis B virus (HBV) as the causative agent. A critical turning point in combating this virus was the development of a preventative vaccine composed of the HBV surface (envelope) protein (HBsAg) to reduce the risk of new infections. The isolation of HBsAg sub-viral particles (SVPs) from the blood of asymptomatic HBV carriers as antigens for the first-generation vaccines, followed by the development of recombinant HBsAg SVPs produced in yeast as the antigenic components of the second-generation vaccines, represent landmark advancements in biotechnology and medicine. The ability of the HBsAg SVPs to accept and present foreign antigenic sequences provides the basis of a chimeric particulate delivery platform, and resulted in the development of a vaccine against malaria (RTS,S/AS01, Mosquirix^TM), and various preclinical vaccine candidates to overcome infectious diseases for which there are no effective vaccines. Biomedical modifications of the HBsAg subunits allowed the identification of strategies to enhance the HBsAg SVP immunogenicity to build potent vaccines for preventative and possibly therapeutic applications. The review provides an overview of the formation and assembly of the HBsAg SVPs and highlights the utilization of the particles in key effective vaccines.

Immunogenicity and safety of a 2-dose hepatitis B vaccine, HBsAg/CpG 1018, in persons with diabetes mellitus aged 60-70 years

BACKGROUND

Hepatitis B virus (HBV) remains a major public health issue, although it is a vaccine-preventable disease. Adults with diabetes are at greater risk of contracting HBV than the general population. Commonly used 3-dose HBV vaccines have reduced immunogenicity in older individuals and in those with diabetes mellitus.

METHODS

In this post hoc analysis of a phase 3 clinical trial, participants with type 2 diabetes mellitus aged 60-70 years received either 2-dose HBsAg/CpG 1018 (HEPLISAV-B®, n = 327) at 0 and 4 weeks and placebo at 24 weeks or 3-dose HBsAg/alum (Engerix-B®, n = 153) at 0, 4, and 24 weeks. Immunogenicity, including seroprotection rate (SPR) at week 28, and safety were assessed by subgroup (sex, body mass index, and smoking status). SPR was defined as antibody against hepatitis B surface antigen serum concentration ≥10 mIU/mL.

RESULTS

The SPR at week 28 was significantly higher with HBsAg/CpG 1018 (85.8% [235/274]) than with HBsAg/alum (58.5% [76/130]) in the per-protocol analysis, for an overall difference of 27.3% (95% CI, 18.0-36.8). SPRs with HBsAg/CpG 1018 were consistently markedly higher compared with HBsAg/alum, regardless of sex, body mass index, or smoking status. Adverse events and deaths were comparable between groups.

CONCLUSIONS

Two-dose HBsAg/CpG 1018 provides a higher level of seroprotection against HBV than does a 3-dose vaccine (HBsAg/alum) with a similar safety profile in patients aged 60-70 years with type 2 diabetes mellitus. Study identifier: NCT02117934.

Factors That Influence the Immune Response to Vaccination

There is substantial variation between individuals in the immune response to vaccination. In this review, we provide an overview of the plethora of studies that have investigated factors that influence humoral and cellular vaccine responses in humans. These include intrinsic host factors (such as age, sex, genetics, and comorbidities), perinatal factors (such as gestational age, birth weight, feeding method, and maternal factors), and extrinsic factors (such as preexisting immunity, microbiota, infections, and antibiotics). Further, environmental factors (such as geographic location, season, family size, and toxins), behavioral factors (such as smoking, alcohol consumption, exercise, and sleep), and nutritional factors (such as body mass index, micronutrients, and enteropathy) also influence how individuals respond to vaccines. Moreover, vaccine factors (such as vaccine type, product, adjuvant, and dose) and administration factors (schedule, site, route, time of vaccination, and coadministered vaccines and other drugs) are also important. An understanding of all these factors and their impacts in the design of vaccine studies and decisions on vaccination schedules offers ways to improve vaccine immunogenicity and efficacy.

Comparative Analysis of B-Cell Receptor Repertoires Induced by Live Yellow Fever Vaccine in Young and Middle-Age Donors

Age-related changes can significantly alter the state of adaptive immune system and often lead to attenuated response to novel pathogens and vaccination. In present study we employed 5′RACE UMI-based full length and nearly error-free immunoglobulin profiling to compare plasma cell antibody repertoires in young (19–26 years) and middle-age (45–58 years) individuals vaccinated with a live yellow fever vaccine, modeling a newly encountered pathogen. Our analysis has revealed age-related differences in the responding antibody repertoire ranging from distinct IGH CDR3 repertoire properties to differences in somatic hypermutation intensity and efficiency and antibody lineage tree structure. Overall, our findings suggest that younger individuals respond with a more diverse antibody repertoire and employ a more efficient somatic hypermutation process than elder individuals in response to a newly encountered pathogen.

Nonimmunity against hepatitis B virus infection in patients newly diagnosed with inflammatory bowel disease

Background/Aims

This study aimed to elucidate the prevalence of hepatitis B virus (HBV) serologic markers in Korean patients newly diagnosed with, but not yet treated for inflammatory bowel disease (IBD).

Methods

We prospectively enrolled 210 patients newly diagnosed with IBD (109 with ulcerative colitis and 101 with Crohn's disease). Hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), and hepatitis B core antibody (anti-HBc) levels were measured and compared with those of 1,100 sex- and age-matched controls.

Results

The prevalence of chronic HBV infection (positive HBsAg, positive anti-HBc, and negative anti-HBs results) and past infection (negative HBsAg, positive anti-HBc, and positive or negative anti-HBs results) were not significantly different between the patients and controls (chronic HBV infection: IBD, 3.8% vs. control, 4.9%, P=0.596; past infection: IBD, 26.2% vs. control, 28.8%, P=0.625). The patients with IBD aged <20 years were at a higher susceptibility risk (nonimmune) for HBV infection than the controls (IBD, 41.5% vs. control, 22.4%; P=0.018). In the multivariate analysis, an age of <20 years (P=0.024) and symptom duration of ≥12 months before diagnosis (P=0.027) were identified as independent risk factors for nonimmunity against HBV infection.

Conclusions

The patients newly diagnosed with IBD were susceptible to HBV infection. The frequency of nonimmunity was high, especially in the patients aged <20 years and those with a longer duration of symptoms before diagnosis. Therefore, it is necessary to screen for HBV serologic markers and generate a detailed vaccination plan for patients newly diagnosed with IBD.

Impaired Immune Response to Primary but Not to Booster Vaccination Against Hepatitis B in Older Adults

Many current vaccines are less immunogenic and less effective in elderly compared to younger adults due to age-related changes of the immune system. Most vaccines utilized in the elderly contain antigens, which the target population has had previous contact with due to previous vaccination or infection. Therefore, most studies investigating vaccine-induced immune responses in the elderly do not analyze responses to neo-antigens but rather booster responses. However, age-related differences in the immune response could differentially affect primary versus recall responses. We therefore investigated the impact of age on primary and recall antibody responses following hepatitis B vaccination in young and older adults. Focused gene expression profiling was performed before and 1 day after the vaccination in order to identify gene signatures predicting antibody responses. Young (20-40 years; n = 24) and elderly (>60 years; n = 17) healthy volunteers received either a primary series (no prior vaccination) or a single booster shot (documented primary vaccination more than 10 years ago). Antibody titers were determined at days 0, 7, and 28, as well as 6 months after the vaccination. After primary vaccination, antibody responses were lower and delayed in the elderly compared to young adults. Non-responders after the three-dose primary series were only observed in the elderly group. Maximum antibody concentrations after booster vaccination were similar in both age groups. Focused gene expression profiling identified 29 transcripts that correlated with age at baseline and clustered in a network centered around type I interferons and pro-inflammatory cytokines. In addition, smaller 8- and 6-gene signatures were identified at baseline that associated with vaccine responsiveness during primary and booster vaccination, respectively. When evaluating the kinetic changes in gene expression profiles before and after primary vaccination, a 33-gene signature, dominated by IFN-signaling, pro-inflammatory cytokines, inflammasome components, and immune cell subset markers, was uncovered that was associated with vaccine responsiveness. By contrast, no such transcripts were identified during booster vaccination. Our results document that primary differs from booster vaccination in old age, in regard to antibody responses as well as at the level of gene signatures.

Clinical Trial Registration

www.clinicaltrialsregister.eu, this trial was registered at the EU Clinical Trial Register (EU-CTR) with the EUDRACT-Nr. 2013-002589-38.

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.

Development of the CpG Adjuvant 1018: A Case Study

The development of aluminum salts (alum) as vaccine adjuvants was an empirical process with little understanding of the mechanism of action and, with decades of use, it has become clear that there is a need for alternatives where alum-based adjuvants are suboptimal. Oligonucleotides containing unmethylated CpG sequences represent one alternative as they are potent stimulators of the vertebrate innate immune system through activation of Toll-like receptor-9. This chapter outlines the methods used by Dynavax Technologies to progress a CpG-containing oligonucleotide sequence termed 1018 through preclinical and clinical testing as an adjuvant for immunization against hepatitis B virus (HBV). 1018 is a short (22-mer) oligonucleotide sequence containing CpG motifs active in both rodents and primates. Preclinical testing of hepatitis B surface antigen (HBsAg) + 1018 in comparison to HBsAg + alum demonstrated induction of substantially higher antibody titers and a favorable safety profile for 1018. Most importantly, clinical studies with HBsAg vaccination consistently demonstrate more rapid induction of protective antibody titers with 1018 compared to alum in all populations studied, including groups that are harder to immunize such as the elderly and immunocompromised individuals. These studies represent the basis for use of the CpG-motif-containing oligonucleotide 1018 as an improved adjuvant for HBsAg immunogenicity. HBsAg + 1018 (HEPLISAV-B^™) is currently in late-stage clinical testing for prophylactic immunization against HBV.

Lifelong Maintenance of Oral Tolerance and Immunity Profiles in Mice Depends on Early Exposure to Antigen

Oral tolerance is defined as a state of systemic hyporesponsiveness to an antigen that has been previously administered by the oral route. Many factors affect oral tolerance induction; some of them related to antigen, and some related to the animal. The age of the animal is one of the most important factors that affect oral tolerance as ageing brings many alterations in immune responses. Herein, we demonstrated that both the oral tolerance and pattern of immune reactivity triggered in early life were kept up to 15 months regarding the magnitude of antibody production, cell proliferation and cytokine profile when compared to immune responses induced in old mice. Therefore, our results corroborate with a promising proposal for prevaccination during childhood and young age, and a booster in older age, to make sure that the primary immunization in early life is not lost in aged individuals.

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.

Immunogenicity and safety of the inactivated Japanese encephalitis vaccine IXIARO® in elderly subjects: Open-label, uncontrolled, multi-center, phase 4 study

BACKGROUND

IXIARO® is a Vero cell-derived, inactivated Japanese encephalitis (JE) vaccine licensed mainly in western countries for children and adults traveling to JE endemic areas. Limited immunogenicity and safety data in elderly travelers have been available.

OBJECTIVES

To evaluate safety and immunogenicity of IXIARO in elderly subjects.

METHODS

Open-label, single arm, multi-centered study. Two-hundred subjects with good general health, including adequately controlled chronic conditions, received two doses of IXIARO®, 28days apart. Protective levels of antibodies were tested 42days after the second dose. Systemic and local adverse events (AEs) were solicited for 7days after each dose, unsolicited AEs were collected up to day 70 and in a phone call at month 7.

SUMMARY OF RESULTS

Subjects were aged 64-83years (median 69.0years). Nineteen percent of subjects had serious or medically attended AEs up to Day 70 (primary endpoint), none of them causally linked to IXIARO. Solicited local AEs were reported by 33.5% (most common: local tenderness) and solicited systemic AEs by 27% (most common: headache) of subjects. The seroprotection rate was 65% with a geometric mean titre (GMT) of 37. Subjects with tick borne encephalitis (TBE) vaccinations in the past 5years (N=29) had a SCR of 90% and GMT of 65.

CONCLUSIONS

IXIARO is generally well tolerated in the elderly, and the safety profile is largely comparable with younger adults. SCR and GMT are lower compared to younger adults, but SCR is in the range reported in elderly for other vaccines e.g. against TBE, hepatitis-A virus (HAV)/hepatitis-B virus (HBV), influenza. The differences in SCR and GMT from younger to elderly adults were in the range of other vaccines. Duration of protection is uncertain in older persons, therefore a booster dose (third dose) should be considered before any further exposure to JE virus.

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.

Characterization of an age-response relationship to GSK's recombinant hepatitis B vaccine in healthy adults: An integrated analysis

The immune system becomes less effective with age, and older age is associated with an increased susceptibility to diseases and reduced responses to vaccination. Furthermore, some adult populations, such as those with diabetes mellitus, are at increased risk of acute hepatitis B virus (HBV) infection. Decreasing responses to vaccination with advanced age have been described, but it is not known at what age immunogenicity starts to reduce, or until what age immunogenicity remains acceptable (for example ≥80 % seroprotection post-vaccination). We characterized the relationship between age and seroprotection rate induced by recombinant HBV vaccination by conducting a pooled analysis of clinical trial data. Healthy adults aged ≥20 y who had been vaccinated with 20μg HBV vaccine (Engerix™ B, GSK Vaccines, Belgium) in a 0, 1, 6 months schedule in 11 studies since 1996 were included. The observed seroprotection rate, defined as an anti-HBV surface antigen antibody concentration ≥10 mIU/ml was 94.5% in the whole population (N = 2,620, Total vaccinated cohort), ranging from 98.6% in adults vaccinated at age 20–24 years, to 64.8% in those vaccinated at age ≥65 y A model on seroprotection rates showed a statistically significant decrease with age, and predicted that the anti-HBs seroprotection rate remains ≥90% up to 49 y of age and ≥80% up to 60 y of age. Individuals at risk of HBV infection should be vaccinated as early in life as possible to improve the likelihood of achieving seroprotection. Additional studies are needed to identify whether unvaccinated individuals older than 60 y would benefit from regimens that include additional or higher vaccine doses.

Immunogenicity, effectiveness and safety of combined hepatitis A and B vaccine: a systematic literature review

BACKGROUND

Hepatitis A and B are two of the most common vaccine-preventable diseases and vaccination for Hepatitis A virus (HAV) and hepatitis B virus (HBV) is recommended for those at risk of contracting HAV and/or HBV through their occupation, travel or lifestyle.

OBJECTIVE

To describe the vaccine efficacy, immunogenicity, effectiveness and safety of the combined vaccine against hepatitis A and hepatitis B.

METHODS

A systematic review of the literature published between 1990 and 2015.

RESULTS

Anti-HAV seropositivity rates ranged from 96.2% to 100% and anti-HBs seroprotection rates from 82% to 100%. Antibodies persisted up to 15 years and geometric mean concentration (GMC) remained above the seropositivity cut-off value for both. Anti-HAV and anti-HBs immune responses were lower in less immunocompetent individuals one month after completion of the immunization schedule. The safety profiles of Twinrix(TM) and monovalent hepatitis A and B vaccines were similar.

CONCLUSION

The vaccine offers satisfactory long-term immunogenicity rates, expected duration of protection and safety profile similar to the monovalent hepatitis A or B vaccines.

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.

How sex and age affect immune responses, susceptibility to infections, and response to vaccination

Do men die young and sick, or do women live long and healthy? By trying to explain the sexual dimorphism in life expectancy, both biological and environmental aspects are presently being addressed. Besides age-related changes, both the immune and the endocrine system exhibit significant sex-specific differences. This review deals with the aging immune system and its interplay with sex steroid hormones. Together, they impact on the etiopathology of many infectious diseases, which are still the major causes of morbidity and mortality in people at old age. Among men, susceptibilities toward many infectious diseases and the corresponding mortality rates are higher. Responses to various types of vaccination are often higher among women thereby also mounting stronger humoral responses. Women appear immune-privileged. The major sex steroid hormones exhibit opposing effects on cells of both the adaptive and the innate immune system: estradiol being mainly enhancing, testosterone by and large suppressive. However, levels of sex hormones change with age. At menopause transition, dropping estradiol potentially enhances immunosenescence effects posing postmenopausal women at additional, yet specific risks. Conclusively during aging, interventions, which distinctively consider the changing level of individual hormones, shall provide potent options in maintaining optimal immune functions.

Enhanced mucosal immune responses induced by a combined candidate mucosal vaccine based on Hepatitis A virus and Hepatitis E virus structural proteins linked to tuftsin

Hepatitis A virus (HAV) and Hepatitis E virus (HEV) are the most common causes of infectious hepatitis. These viruses are spread largely by the fecal-oral route and lead to clinically important disease in developing countries. To evaluate the potential of targeting hepatitis A and E infection simultaneously, a combined mucosal candidate vaccine was developed with the partial open reading frame 2 (ORF2) sequence (aa 368–607) of HEV (HE-ORF2) and partial virus protein 1 (VP1) sequence (aa 1–198) of HAV (HA-VP1), which included the viral neutralization epitopes. Tuftsin is an immunostimulatory peptide which can enhance the immunogenicity of a protein by targeting it to macrophages and dendritic cells. Here, we developed a novel combined protein vaccine by conjugating tuftsin to HE-ORF2 and HA-VP1 and used synthetic CpG oligodeoxynucleotides (ODNs) as the adjuvant. Subsequent experiments in BALB/c mice demonstrated that tuftsin enhanced the serum-specific IgG and IgA antibodies against HEV and HAV at the intestinal, vaginal and pulmonary interface when delivered intranasally. Moreover, mice from the intranasally immunized tuftsin group (HE-ORF2-tuftsin + HA-VP1-tuftsin + CpG) showed higher levels of IFN-γ-secreting splenocytes (Th1 response) and ratio of CD4⁺/CD8⁺ T cells than those of the no-tuftsin group (HE-ORF2 + HA-VP1 + CpG). Thus, the tuftsin group generated stronger humoral and cellular immune responses compared with the no-tuftsin group. Moreover, enhanced responses to the combined protein vaccine were obtained by intranasal immunization compared with intramuscular injection. By integrating HE-ORF2, HA-VP1 and tuftsin in a vaccine, this study validated an important concept for further development of a combined mucosal vaccine against hepatitis A and E infection.

Persistence of immunity in healthy adults aged ≥ 50 years primed with a hepatitis B vaccine 3 years previously

Hepatitis B vaccines do not generate protective immune responses in older adults as effectively as they do in children and young adults. Improved formulations of existing vaccines may have the potential to improve this. This study investigated the persistence of serum antibodies against hepatitis B surface antigens (anti-HBs) 3.1-3.5 years following primary vaccination with 3 doses of HBvaxPRO® or Engerix B™ in healthy adults aged ≥ 50 years who were further challenged with 1 dose of recombinant hepatitis B antigen. This was an open-label extension study. Individuals (N = 204) with a mean (standard deviation) age at enrollment of 63.7 (7.0) years receiving HBvaxPRO® or Engerix B™ in a randomized, double-blind primary study were challenged with 1 dose of HBvaxPRO® (10 μg). Anti-HBs were measured pre- and 30 days post-challenge. 45.5% (34.8, 56.4 [95% CI]) of individuals who received HBvaxPRO® in the per protocol set (PPS) had anti-HBs titers ≥ 10 mIU/mL pre-challenge and 85.2% (76.1, 91.9) 1-month post-challenge. In those who received Engerix B™ in the primary vaccination series, the results were 58.8% (48.6, 68.5) and 88.3% (80.5, 93.8), respectively. The challenge dose of HBvaxPRO® was generally well tolerated. Subjects aged ≥ 50 years receiving a challenge dose of HBvaxPRO® demonstrated immune memory against hepatitis B 3 years after a 3-dose primary. The safety profile of this challenge dose of HBvaxPRO® was consistent with the well-established safety profile of the vaccine HBvaxPRO®.

Prophylactic vaccination against hepatitis B: achievements, challenges and perspectives

Large-scale vaccination against hepatitis B virus (HBV) infection started in 1984 with first-generation vaccines made from plasma of chronic carriers containing HBV surface antigen (HBsAg). Thereafter, it was replaced in most countries by second-generation vaccines manufactured in yeast cells transformed with gene S encoding HBsAg. Both generations of vaccines have been applied for universal neonate and early childhood vaccination worldwide and have led to a 70-90 % decrease in chronic HBV carrier rates. However, 10-30% of newborns from HBsAg/HBeAg-positive mothers cannot be protected by passive/active vaccination alone and become chronic HBV carriers themselves. Asymptomatic occult HBV infections are frequent even in those who have protective levels of anti-HBs. Suboptimal protection may be due to heterologous HBsAg subtypes that are present in 99% of HBV carriers worldwide. Second-generation vaccines contain partially misfolded HBsAg and lack preS1 antigen that carries the major HBV attachment site and neutralizing epitopes. Third-generation vaccines produced in mammalian cells contain correctly folded HBsAg and neutralizing epitopes of the preS antigens, induce more rapid protection, overcome nonresponse to second-generation vaccines and, most importantly, may provide better protection for newborns of HBV-positive mothers. PreS/S vaccines expressed in mammalian cells are more expensive to manufacture, but introduction of more potent HBV vaccines should be considered in regions with a high rate of vertical transmission pending assessment of health economics and healthcare priorities. With optimal vaccines and vaccination coverage, eradication of HBV would be possible.

Vaccinations in older adults with gastrointestinal diseases

Vaccines play a key role in the prevention of illness in the elderly, are cost effective, and generally safe. Hepatitis C, cirrhosis, autoimmune hepatitis, and inflammatory bowel disease are more prevalent than ever among older adults. Along with an age-related decline in immune system function (immunosenescence), these diseases make elderly individuals more susceptible to infections and more likely to experience a poor outcome relative to their younger counterparts. Vaccinations also appear to be less effective in the elderly, warranting research into different vaccination strategies such as booster vaccines, higher doses of vaccine, and measurement of antibody titers to guide vaccination.

A double-dose hepatitis B vaccination schedule in travelers presenting for late consultation

BACKGROUND

Vaccination against hepatitis B virus (HBV) is recommended for all travelers visiting HBV-endemic countries. However, travelers often present with insufficient time for the standard HBV vaccine schedule (SVS). We examined seroprotection against HBV following an alternative two-visit vaccination schedule (TVS) with currently available vaccine products, and completion rates with this TVS.

METHODS

A retrospective cohort study was conducted in three travel clinics in British Columbia, Canada. Adults ≥20 years old traveling to an HBV-endemic country, and unable to complete the standard or rapid HBV vaccination schedule before departure, were offered a TVS that consisted of a double dose of HBV vaccine at day 0, followed by a single dose in 4 to 12 months. Immunity to HBV [anti-HBV surface antigen (HBs) ≥10 mIU/mL] was determined 1 to 6 months following the final dose of HBV vaccine. Logistic regression modeling was used to assess correlates of seroprotection. We also determined completion rate with this TVS at two clinics.

RESULTS

In total, 117 participants (age range, 21-81 years, median age 57) met the inclusion criteria. Of these, 97 (82.9%) were immune after the TVS. Immunity was demonstrated in 93.1% of patients <50 years old and 79.5% of patients ≥50 years old. Increasing age was associated with reduced odds of developing immunity to HBV using the TVS [adjusted odds ratio = 0.954, 95% confidence interval (CI): 0.904, 1.008]. The completion rate of the TVS was 32.6% over a 12-month period. Completion rates varied between clinics (23.5% vs 48.4%, p < 0.001), suggesting that clinic-specific follow-up policies were important.

CONCLUSION

Seroprotection with completion of this TVS was similar to or exceeded that published in the literature for the SVS by age. However, even with a TVS, completion rates were low, underscoring the importance of follow-up. Further research is needed to determine whether travelers are protected prior to completion of this TVS.

A systems biology approach to the effect of aging, immunosenescence and vaccine response

Aging can lead to immunosenescence, which dramatically impairs the hosts' ability to develop protective immune responses to vaccine antigens. Reasons for this are not well understood. This topic's importance is reflected in the increases in morbidity and mortality due to infectious diseases among elderly persons, a population growing in size globally, and the significantly lower adaptive immune responses generated to vaccines in this population. Here, we endeavor to summarize the existing data on the genetic and immunologic correlates of immunosenescence with respect to vaccine response. We cover how the application of systems biology can advance our understanding of vaccine immunosenescence, with a view toward how such information could lead to strategies to overcome the lower immunogenicity of vaccines in the elderly.

Hepatitis B vaccine immunogenicity among adults vaccinated during an outbreak response in an assisted living facility--Virginia, 2010

BACKGROUND

Failure to adhere to infection control guidelines, especially during assisted monitoring of blood glucose, has caused multiple hepatitis B outbreaks in assisted living facilities (ALFs). In conjunction with the response to such an outbreak at an ALF ("Facility X") where most residents had neuropsychiatric disorders, we evaluated seroprotection rates conferred by hepatitis B vaccine and assessed the influence of demographic factors on vaccine response.

METHODS

Residents were screened for hepatitis B and C infection, and those susceptible were vaccinated against hepatitis A and hepatitis B with one dose of TWINRIX™ (GSK) given at 0, 1, and 7 months. Blood samples were collected 1-2 months after receipt of the third vaccine dose to test for antibody to hepatitis B surface antigen (anti-HBs).

RESULTS

Of the 27 residents who had post-vaccination blood specimens collected, 22 (81%) achieved anti-HBs concentrations ≥10 mIU/mL. Neither age nor neuropsychiatric comorbidity was a significant determinant of seroprotection. Geometric mean concentration was lower among residents aged 60-74 years (74.3 mIU/mL) than among residents aged 46-59 years (105.3 mIU/mL) but highest among residents aged ≥75 years (122.5 mIU/mL). The effect of diabetes on vaccination response could not be examined because 16/17 (94%) diabetic residents had HBV infection by the time of investigation.

CONCLUSIONS

Adult vaccine recipients of all ages, even those over 60 years of age, demonstrated a robust capacity for achieving hepatitis B seroprotection in response to the combined hepatitis A/hepatitis B vaccine. The role for vaccination in interrupting HBV transmission during an outbreak remains unclear, but concerns about age-related response to hepatitis B vaccine may be insufficient to justify foregoing vaccination of susceptible residents of ALFs.

Medical virology of hepatitis B: how it began and where we are now

Infection with hepatitis B virus (HBV) may lead to acute or chronic hepatitis. HBV infections were previously much more frequent but there are still 240 million chronic HBV carriers today and ca. 620,000 die per year from the late sequelae liver cirrhosis or hepatocellular carcinoma. Hepatitis B was recognized as a disease in ancient times, but its etiologic agent was only recently identified. The first clue in unraveling this mystery was the discovery of an enigmatic serum protein named Australia antigen 50 years ago by Baruch Blumberg. Some years later this was recognized to be the HBV surface antigen (HBsAg). Detection of HBsAg allowed for the first time screening of inapparently infected blood donors for a dangerous pathogen. The need to diagnose clinically silent HBV infections was a strong driving force in the development of modern virus diagnostics. HBsAg was the first infection marker to be assayed with a highly sensitive radio immune assay. HBV itself was among the first viruses to be detected by assay of its DNA genome and IgM antibodies against the HBV core antigen were the first to be selectively detected by the anti-μ capture assay. The cloning and sequencing of the HBV genome in 1978 paved the way to understand the viral life cycle, and allowed development of efficient vaccines and drugs. Today’s hepatitis B vaccine was the first vaccine produced by gene technology. Among the problems that still remain today are the inability to achieve a complete cure of chronic HBV infections, the recognition of occult HBV infections, their potential reactivation and the incomplete protection against escape mutants and heterologous HBV genotypes by HBV vaccines.

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.

Systems biology of vaccination in the elderly

Aging population demographics, combined with suboptimal vaccine responses in the elderly, make the improvement of vaccination strategies in the elderly a developing public health issue. The immune system changes with age, with innate and adaptive cell components becoming increasingly dysfunctional. As such, vaccine responses in the elderly are impaired in ways that differ depending on the type of vaccine (e.g., live attenuated, polysaccharide, conjugate, or subunit) and the mediators of protection (e.g., antibody and/or T cell). The rapidly progressing field of systems biology has been shown to be useful in predicting immunogenicity and offering insights into potential mechanisms of protection in young adults. Future application of systems biology to vaccination in the elderly may help to identify gene signatures that predict suboptimal responses and help to identify more accurate correlates of protection. Moreover, the identification of specific defects may be used to target novel vaccination strategies that improve efficacy in elderly populations.

Mechanistic insights into the impairment of memory B cells and antibody production in the elderly

It is well established that immunologic memory generated early in life can be maintained into old age and mediate robust anamnestic antibody responses. Little is known, however, about the initiation of memory B cells in the elderly. We have conducted a prospective analysis of the quantities and functionalities of antigen-specific B cell responses and its association with the functional helper CD4(+)T cell responses. The ability of naïve B cells from old (60-80 years) and young (20-31 years) humans to establish functional memory was examined following primary and booster vaccination with an inactivated-virus vaccine against tick-borne encephalitis. Our data show that the number of antigen-specific memory B cells generated during primary vaccination was ~3-fold lower in old than in young individuals. The maintenance and booster responsiveness of these memory B cells were not compromised, as evidenced by similar increases in specific memory B cell frequencies upon revaccination in old and young adults. In contrast, the Ab response mediated per memory B cell after revaccination was dramatically diminished in the elderly. Also, antigen-specific IL-2-positive CD4(+)T cell responses were strongly reduced in the elderly and displayed an excellent correlation with Ab titres. The data suggest that the dramatically lower antibody response in the elderly could only partially be accounted for by the reduced B cell numbers and was strongly correlated with profound functional defects in CD4 help.

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.

Characterization of MHC-II antigen presentation by B cells and monocytes from older individuals

In this study we examine the effects of aging on antigen presentation of B cells and monocytes. We compared the antigen presentation function of peripheral blood B cells from young and old subjects using a system that specifically measures the B cell receptor (BCR)-mediated MHC-II antigen presentation. Monocytes were studied as well. Overall the mean magnitude of antigen presentation of soluble antigen and peptide was not different in older and younger subjects for both B cells and monocytes. Older subjects, however, showed increased heterogeneity of BCR-mediated antigen presentation by their B cells. The magnitude and variability of peptide presentation, which do not require uptake and processing, were the same between groups. Presentation by monocytes had similar variability between the older and younger subjects. These data suggest that poor B cell antigen processing, which results in diminished presentation in some older individuals may contribute to poor vaccine responses.

Relationship between systemic inflammation and delayed-type hypersensitivity response to Candida antigen in older adults

Research has shown that aging is associated with increased systemic inflammation as well as a reduction in the strength of immune responses. However, little evidence exists linking the decrease in cell-mediated immunity in older adults with other health parameters. We sought to examine the relationship between cell-mediated immunity as measured in vivo by the delayed-type hypersensitivity (DTH) response to candida antigen and demographic and physiological variables in older (65–80 y.o.) adults. Candida antigen response was not related to gender or obesity, or to a number of other physiological variables including fitness and body composition. However, positive responders had significantly lower serum C-reactive protein levels (CRP, p<0.05) vs. non-responders. Furthermore, subjects with CRP<4.75 mg•L⁻¹ had greater odds of developing a positive response compared to those with CRP>4.75 mg•L⁻¹. Therefore, positive responses to candida antigen in older adults appears to be related to lower levels of systemic inflammation.

Hepatitis B vaccination of susceptible elderly residents of long term care facilities during a hepatitis B outbreak

Protection of older persons, particularly those with diabetes, against hepatitis B virus (HBV) infection is of growing concern because of increased reports of outbreaks among long-term care facility residents receiving assisted blood glucose monitoring. We evaluated hepatitis B vaccine immunogenicity among residents immunized in response to two such outbreaks in skilled nursing facilities during June 2009-July 2010. One hundred forty-eight (71%) of 209 residents were found to be susceptible to HBV infection. Of 105 patients who began a vaccination series with Twinrix(®) (0-, 1-, 6-month dosing), 86 (82%) completed the series and postvaccination testing. Of these, most were elderly (median age 79.5 years; range 45-101), female (56%), and African-American (51%). Twenty-nine (34%) vaccinated residents had post-vaccination hepatitis B surface antibody levels ≥10 mIU/ml. There were no significant differences in vaccine response by age, gender, race, diabetes status, body mass index, or current smoking status. Our findings indicate that a low proportion of skilled nursing facility residents achieved a seroprotective response after hepatitis B vaccination.

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.

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.

High specificity of line-immunoassay based algorithms for recent HIV-1 infection independent of viral subtype and stage of disease

Background

Serologic testing algorithms for recent HIV seroconversion (STARHS) provide important information for HIV surveillance. We have shown that a patient's antibody reaction in a confirmatory line immunoassay (INNO-LIA^TM HIV I/II Score, Innogenetics) provides information on the duration of infection. Here, we sought to further investigate the diagnostic specificity of various Inno-Lia algorithms and to identify factors affecting it.

Methods

Plasma samples of 714 selected patients of the Swiss HIV Cohort Study infected for longer than 12 months and representing all viral clades and stages of chronic HIV-1 infection were tested blindly by Inno-Lia and classified as either incident (up to 12 m) or older infection by 24 different algorithms. Of the total, 524 patients received HAART, 308 had HIV-1 RNA below 50 copies/mL, and 620 were infected by a HIV-1 non-B clade. Using logistic regression analysis we evaluated factors that might affect the specificity of these algorithms.

Results

HIV-1 RNA <50 copies/mL was associated with significantly lower reactivity to all five HIV-1 antigens of the Inno-Lia and impaired specificity of most algorithms. Among 412 patients either untreated or with HIV-1 RNA ≥50 copies/mL despite HAART, the median specificity of the algorithms was 96.5% (range 92.0-100%). The only factor that significantly promoted false-incident results in this group was age, with false-incident results increasing by a few percent per additional year. HIV-1 clade, HIV-1 RNA, CD4 percentage, sex, disease stage, and testing modalities exhibited no significance. Results were similar among 190 untreated patients.

Conclusions

The specificity of most Inno-Lia algorithms was high and not affected by HIV-1 variability, advanced disease and other factors promoting false-recent results in other STARHS. Specificity should be good in any group of untreated HIV-1 patients.

The use of dried blood spots for assessing antibody response to hepatitis A virus after natural infection and vaccination

During recent years, vaccination against hepatitis A has been implemented in several countries. It is expected that the increase in mass vaccination against hepatitis A will eventually result in a decreased prevalence of anti-HAV antibodies in the general population. For this reason, a suitable clinical sample for diagnosis of hepatitis A must be sufficiently sensitive to enable detection of lower antibodies titers. In this study, the feasibility of using dried blood spots (DBS) was assessed for the detection of anti-HAV antibodies after a natural infection and vaccination. Seventy-four DBS and paired plasma samples were obtained from a group of college students for a cross-sectional hepatitis A seroepidemiological study. Forty-six students seronegative for anti-HAV were selected randomly and immunized with an inactivated hepatitis A vaccine using an 0-6 month schedule. Seroconversion was monitored in paired plasma and DBS samples 6 months after the first dose followed by a period of 8 and 24 months after the second dose. A strong correlation between OD/CO rates of paired plasma and DBS samples for the detection of anti-HAV was observed. The sensitivity and specificity of the DBS compared with plasma for the detection of anti-HAV antibodies after natural infection was 100%. The sensitivity of DBS in samples collected 24 months after the second dose of hepatitis A vaccine was 95.4%. The results showed that DBS samples can be used for the detection of anti-HAV antibodies both after natural infection or vaccination.

[Prevention of virus hepatitis A to E]

Infection with hepatitis viruses can lead to acute hepatitis with the risk of developing liver failure. Chronic viral hepatitis may evolve into liver cirrhosis and hepatocellular carcinoma. Thus, prevention of viral hepatitis and its sequels is essential. Vaccination against hepatitis A is successful in almost all individuals. Protective antibodies maintain for at least 20 years. Booster vaccinations are not necessary. Since the introduction of hepatitis A vaccines, the incidence of new HAV-infections has declined significantly. Hepatitis B vaccines are safe and highly effective. Special populations such as dialysis patients or immunocompromised patients require special vaccine schedules. New vaccines with improved adjuvants are currently being tested in clinical trials. So far there is no hepatitis C vaccine on the horizon. Prophylaxis of HCV-infections relies primarily on hygiene measures. Early therapy of acute hepatitis C can prevent chronic hepatitis C. HDV-infection can only be established if HBsAg is present. Thus, prevention of hepatitis B or elimination of HBsAg means prevention of hepatitis delta. Hepatitis E vaccines have been evaluated in phase III studies. The development of HEV vaccines becomes more relevant since chronic HEV infections have been reported in immunosuppressed individuals.