Long-term immunogenicity and safety of an investigational herpes zoster subunit vaccine in older adults

Immunogenicity of Recombinant Zoster Vaccine: A Systematic Review, Meta-Analysis, and Meta-Regression

BACKGROUND

The adjuvanted recombinant zoster vaccine (RZV), consisting of varicella-zoster virus glycoprotein E (gE) and the AS01B adjuvant system, effectively prevents herpes zoster (HZ). In the absence of a well-defined correlate of protection, it is important to monitor the RZV immune response, as a proxy of clinical effectiveness.

METHODS

This systematic review examined post-vaccination parameters: humoral and cell-mediated immunity, avidity index, geometric mean concentration of antibody (GMC), and immunity persistence. The meta-analysis used a random-effects model, and subgroup and meta-regression analyses were conducted.

RESULTS

Among 37 included articles, after one month from RZV-dose 2, the pooled response rate for anti-gE humoral immunity was 95.2% (95%CI 91.9-97.2), dropping to 77.6% (95%CI 64.7-86.8) during immunosuppression. The anti-gE cell-mediated immunity-specific response reached 84.6% (95%CI 75.2-90.9). Varying factors, such as age, sex, coadministration with other vaccines, prior HZ, or live-attenuated zoster vaccine, did not significantly affect response rates. RZV induced a substantial increase in gE avidity. Immunity persistence was confirmed, with more rapid waning in the very elderly.

CONCLUSIONS

This systematic review indicates that RZV elicits robust immunogenicity and overcomes immunocompromising conditions. The findings underscore the need for further research, particularly on long-term immunity, and have the potential to support HZ vaccination policies and programs.

CHO cells for virus-like particle and subunit vaccine manufacturing

Chinese Hamster Ovary (CHO) cells, employed primarily for manufacturing monoclonal antibodies and other recombinant protein (r-protein) therapeutics, are emerging as a promising host for vaccine antigen production. This is exemplified by the recently approved CHO cell-derived subunit vaccines (SUV) against respiratory syncytial virus (RSV) and varicella-zoster virus (VZV), as well as the enveloped virus-like particle (eVLP) vaccine against hepatitis B virus (HBV). Here, we summarize the design, production, and immunogenicity features of these vaccine and review the most recent progress of other CHO-derived vaccines in pre-clinical and clinical development. We also discuss the challenges associated with vaccine production in CHO cells, with a focus on ensuring viral clearance for eVLP products.

The durability of vaccine-induced protection: an overview

INTRODUCTION

Current vaccines vary widely in both their efficacy against infection and disease, and the durability of the efficacy. Some vaccines provide practically lifelong protection with a single dose, while others provide only limited protection following annual boosters. What variables make vaccine-induced immune responses last? Can breakthroughs in these factors and technologies help us produce vaccines with better protection and fewer doses? The durability of vaccine-induced protection is now a hot area in vaccinology research, especially after COVID-19 vaccines lost their luster. It has fueled discussion on the eventual utility of existing vaccines to society and bolstered the anti-vaxxer camp. To sustain public trust in vaccines, lasting vaccines must be developed.

AREAS COVERED

This review summarizes licensed vaccines' protection. It analyses immunological principles and vaccine and vaccinee parameters that determine longevity of antibodies. The review concludes with challenges and the way forward to improve vaccine durability.

EXPERT OPINION

Despite enormous advances, we still lack essential markers and reliable correlates of lasting protection. Most research has focused on humoral immune responses, but we must also focus on innate, mucosal, and cellular responses - their assessment, correlates, determinants, and novel adjuvants. Suitable vaccine designs and platforms for durable immunity must be found.

Public health impact of herpes zoster vaccination on older adults in Hong Kong

The growing burden of herpes zoster (HZ) in Hong Kong, due to an aging population with increasing life expectancy, may be reduced by vaccination. This study aimed to estimate public health impact of HZ vaccination in Hong Kong. The ZOster ecoNomic Analysis (ZONA) model was adapted with Hong Kong-specific key model inputs/assumptions, where available. Base case analysis involved adults ≥50 years of age (YOA), exploring three vaccination strategies (no vaccination/recombinant zoster vaccine [RZV]/zoster vaccine live [ZVL]) under private market (5% coverage) and mass vaccination (40% coverage) settings. Scenario and sensitivity analyses were performed. In the base case population (3.13 million), without vaccination, 891,024 HZ (28.4%), 156,097 post-herpetic neuralgia (PHN) (5.0%), and 38,755 (1.2%) HZ ophthalmicus (HZO) were projected over their remaining lifetime. Mass RZV vaccination reduced HZ, PHN, and HZO cases by 204,875 (-23.0%), 31,949 (-20.5%), and 8,471 (-21.9%), respectively, which was 4-5 times that reduced with ZVL. RZV was more efficient than ZVL, with lower number needed to vaccinate to prevent one HZ/PHN/HZO case (RZV: 7/40/148; ZVL: 27/163/709). Among all age cohorts, the greatest reduction in cases was projected for RZV (versus no vaccination/ZVL) in the youngest cohort, 50-59 YOA. Results were robust under scenario and sensitivity analyses. HZ burden in Hong Kong is substantial. Mass RZV vaccination is expected to considerably reduce public health burden of HZ among individuals ≥50 YOA, compared with no vaccination/ZVL. Results may support value assessment and decision-making regarding vaccination strategies for HZ prevention in Hong Kong.

Advancements in Vaccine Adjuvants: The Journey from Alum to Nano Formulations

Vaccination is a groundbreaking approach in preventing and controlling infectious diseases. However, the effectiveness of vaccines can be greatly enhanced by the inclusion of adjuvants, which are substances that potentiate and modulate the immune response. This review is based on extensive searches in reputable databases such as Web of Science, PubMed, EMBASE, Scopus, and Google Scholar. The goal of this review is to provide a thorough analysis of the advances in the field of adjuvant research, to trace the evolution, and to understand the effects of the various adjuvants. Historically, alum was the pioneer in the field of adjuvants because it was the first to be approved for use in humans. It served as the foundation for subsequent research and innovation in the field. As science progressed, research shifted to identifying and exploiting the potential of newer adjuvants. One important area of interest is nano formulations. These advanced adjuvants have special properties that can be tailored to enhance the immune response to vaccines. The transition from traditional alum-based adjuvants to nano formulations is indicative of the dynamism and potential of vaccine research. Innovations in adjuvant research, particularly the development of nano formulations, are a promising step toward improving vaccine efficacy and safety. These advances have the potential to redefine the boundaries of vaccination and potentially expand the range of diseases that can be addressed with this approach. There is an optimistic view of the future in which improved vaccine formulations will contribute significantly to improving global health outcomes.

A metabolic blueprint of COVID-19 and long-term vaccine efficacy

Viruses are obligatory protein-coated units and often utilize the metabolic functions of the cells they infect. Viruses hijack cellular metabolic functions and cause consequences that can range from minor to devastating, as we have all witnessed during the COVID-19 pandemic. For understanding the virus-driven pathogenesis and its implications on the host, the cellular metabolism needs to be elucidated. How SARS-CoV-2 triggers metabolic functions and rewires the metabolism remains unidentified but the implications of the metabolic patterns are under investigation by several researchers. In this review, we have described the SARS-CoV-2-mediated metabolic alterations from in vitro studies to metabolic changes reported in victims of COVID-19. We have also discussed potential therapeutic targets to diminish the viral infection and suppress the inflammatory response, with respect to evidenced studies based on COVID-19 research. Finally, we aimed to explain how we could extend vaccine-induced immunity in people by targeting the immunometabolism.

Lipid nanoparticles technology in vaccines: Shaping the future of prophylactic medicine

Throughout decades, the intrinsic power of the immune system to fight pathogens has inspired researchers to develop techniques that enable the prevention or treatment of infections via boosting the immune response against the target pathogens, which has led to the evolution of vaccines. The recruitment of Lipid nanoparticles (LNPs) as either vaccine delivery platforms or immunogenic modalities has witnessed a breakthrough recently, which has been crowned with the development of effective LNPs-based vaccines against COVID-19. In the current article, we discuss some principles of such a technology, with a special focus on the technical aspects from a translational perspective. Representative examples of LNPs-based vaccines against cancer, COVID-19, as well as other infectious diseases, autoimmune diseases, and allergies are highlighted, considering the challenges and promises. Lastly, the key features that can improve the clinical translation of this area of endeavor are inspired.

Insights into the Novel Therapeutics and Vaccines against Herpes Simplex Virus

Herpes simplex virus (HSV) is a great concern of the global health community due to its linked infection of inconspicuous nature and resultant serious medical consequences. Seropositive patients may develop ocular disease or genital herpes as characteristic infectious outcomes. Moreover, the infectious nature of HSV is so complex that the available therapeutic options have been modified in certain ways to cure it. However, no permanent and highly effective cure has been discovered. This review generates insights into the available prophylactic and therapeutic interventions against HSV. A methodological research approach is used for study design and data complication. Only the latest data from publications are acquired to shed light on updated therapeutic approaches. These studies indicate that the current antiviral therapeutics can suppress the symptoms and control viral transmission up to a certain level, but cannot eradicate the natural HSV infection and latency outcomes. Most trials that have entered the clinical phase are made part of this review to understand what is new within the field. Some vaccination approaches are also discussed. Moreover, some novel therapeutic options that are currently in research annals are given due consideration for future development. The data can enable the scientific community to direct their efforts to fill the gaps that remain unfilled in terms of therapies for HSV. The need is to integrate scientific efforts to produce a proper cure against HSV to control the virus spread, resistance, and mutation in future disease management.

Safety and efficacy of recombinant and live herpes zoster vaccines for prevention in at-risk adults with chronic diseases and immunocompromising conditions

Compared with the general population, older adults with immune senescence and individuals who are immunocompromised (IC) due to disease or immunosuppressive therapy are at increased risk for herpes zoster (HZ) and its associated complications, which can be debilitating and life-threatening. Vaccination can be an effective strategy against HZ and studies have shown that HZ vaccination in IC individuals can elicit immune responses and provide protection from infection. Recently, the first approvals have been granted in the United States and the European Union for the recombinant HZ vaccine (RZV) in adults ≥ 18 years of age at risk of HZ due to immunodeficiency or immunosuppression. Existing systematic reviews have highlighted the risks for HZ in limited immunocompromising conditions and have only examined clinical data for RZV. This review details the risks and burden of HZ in a broad range of clinically relevant IC populations and summarizes key efficacy and safety data for RZV and live HZ vaccine in these individuals. Research has shown IC individuals can benefit from HZ vaccination; however, these insights have yet to be fully incorporated into vaccination guidelines and clinical care. Clinicians should consider HZ vaccination in eligible at-risk populations to protect against HZ and its associated complications and thereby, reduce the burden that HZ poses on the healthcare system. Electronic health records and linked personal health records could be used to identify and contact patients eligible for HZ vaccination and provide clinical decision support-generated alerts for missing or delayed vaccinations. This review will help clinicians identify eligible IC individuals who may benefit from HZ vaccination. A video abstract linked to this article is available on Figshare https://doi.org/10.6084/m9.figshare.21517605.

Epidemiology of Herpes Zoster in Adults in Mexico: A Retrospective Database Analysis

INTRODUCTION

The risk of herpes zoster (HZ) increases with age. In countries with an ageing population such as Mexico, a rise in the risk of HZ and complications is expected. The goal of this study was to provide an updated estimate of the potential burden of HZ and associated complications in Mexico.

METHODS

A retrospective database study was performed using data from the national surveillance database of the Ministry of Health (Secretaría de Salubridad y Asistencia/Dirección General de Información en Salud). HZ cases and associated complications were identified via the International Classification of Diseases 10th Revision codes. Emergency room (ER) visits, hospitalizations, and deaths were extracted and analyzed by age group and year. The observation period was between 2011 and 2020 for ER visits and hospitalizations and between 2011 and 2019 for deaths. Cumulative incidence per 1000 people and case fatality rate were estimated.

RESULTS

During the observation period, 53,030 ER visits, 4172 hospitalizations, and 263 deaths due to HZ were reported nationwide. The cumulative incidence of HZ based on ER visits was 1.04 per 1000 people aged ≥ 50 years but increased in older age groups (1.47 per 1000 people aged ≥ 65 years). The most common complications were neuralgia (10.9%), ocular disease (7.0%), meningoencephalitis (2.9%), and disseminated disease (3.1%). Patients ≥ 65 years accounted for 37% of hospitalizations and 81% of deaths.

CONCLUSION

In Mexico, HZ and its complications impose a considerable burden on the population and the healthcare system. Prospective surveillance studies are required to obtain an accurate picture of the current epidemiology of HZ in Mexico and to estimate the benefits of future vaccination strategies against HZ.

Lifetime risk of herpes zoster in the population of Beijing, China

Objectives

We aimed to estimate the current and future lifetime risks (LTR) of herpes zoster (HZ) and postherpetic neuralgia (PHN), as well as their respective number of annual incident cases in Beijing, China, if individuals were not vaccinated against HZ.

Study design

Mathematical model built in Microsoft Excel, de novo.

Methods

A hypothetical cohort of 1,000 people was simulated from age 0-100 or until death to generate LTRs of HZ/PHN in Beijing, China. LTR was defined as the risk of developing HZ/PHN at least once in the person's lifetime. The current number of annual incident HZ/PHN cases were also calculated by multiplying up-to-date population data and the annual age-specific incidence of HZ/PHN. For both LTR and annual incident cases, current estimates were projected into the year 2035 to investigate the impact of an aging population. Scenario and deterministic sensitivity analyses (DSA) were conducted to validate the model outcomes.

Results

In Beijing, the current and future LTRs of HZ (PHN) were 32.4% (2.8%) and 34.8% (3.3%), respectively. The current and future annual incident cases of HZ (PHN) of individuals aged ≥50 years were 68,394 (7,801) cases among 7.04 million individuals and 88,676 (9,649) cases among 9.08 million individuals, respectively. The scenario analyses demonstrated that modelled results were likely to underestimate the LTR of HZ. Results were robust under the DSA.

Conclusions

Given an aging population, HZ poses a significant, growing burden on individuals, the society, and healthcare system of China, highlighting the need for preventative measures such as vaccination.

Immunogenicity of Varicella Zoster Virus DNA Vaccines Encoding Glycoprotein E and Immediate Early Protein 63 in Mice

Herpes zoster (HZ) is caused by the reactivation of latent varicella-zoster virus (VZV) from the sensory ganglia due to aging or immunosuppression. Glycoprotein E (gE) is a widely used vaccine antigen for specific humoral and cellular immune responses. Immediate early protein 63 (IE63) is expressed during latency, suggesting that it is a potential antigen against HZ reactivation. In this study, HZ DNA vaccines encoding gE, IE63, IE63-2A-gE (where 2A is a self-cleaving sequence), or IE63-linker-gE were developed and investigated for immunogenicity in mice. The results showed that each HZ DNA vaccine induced VZV-specific antibody production. The neutralizing antibody titer elicited by IE63-2A-gE was comparable to that elicited by gE or live attenuated HZ vaccine (LAV). IE63-2A-gE-induced gE or IE63-specific INF-γ⁺ T cell frequencies in splenocytes were comparable to those of LAV. Furthermore, IE63-2A-gE, gE, or IE63 led to a significant increase in IFN-γ (IE63 stimulation) and IL-2 (gE stimulation) secretion compared to LAV, showing a Th1-biased immune response. Moreover, IE63-2A-gE and gE induced cytotoxic activity of CD8⁺ T cells compared to that of LAV. This study elucidates that the IE63-2A-gE DNA vaccine can induce both humoral and cell-mediated immune responses, which provides a candidate for the development of an HZ vaccine.

Immune Responses to Varicella-Zoster Virus Vaccines

The live attenuated varicella vaccine is intended to mimic the tempo and nature of the humoral and cell-mediated immune responses to varicella infection. To date, two doses of varicella vaccine administered in childhood have been very effective in generating varicella-zoster virus (VZV) immune responses that prevent natural infection for at least several decades. After primary infection, the infecting VZV establishes latency in sensory and cranial nerve ganglia with the potential to reactivate and cause herpes zoster. Although, the immune responses developed during varicella are important for preventing herpes zoster they wane with increasing age (immune senescence) or with the advent of immune suppression. Protection can be restored by increasing cell-mediated immune responses with two doses of an adjuvanted recombinant VZV glycoprotein E vaccine that stimulates both VZV-and gE-specific immunity. This vaccine provides ~85-90% protection against herpes zoster for 7-8 years (to date).

Immune response of C57BL/6J mice to herpes zoster subunit vaccines formulated with nanoemulsion-based and liposome-based adjuvants

Herpes zoster (HZ) is a recurrent nerve tissue infection caused by the reactivation of varicella-zoster virus (VZV). At present, two vaccines, the live attenuated vaccine Zostavax™ and AS01B-adjuvanted recombinant subunit vaccine Shingrix™, are commercially available for HZ. The latter is superior to the former in terms of efficacy and duration of immunity in the elderly. In this study, we used glycoprotein E (gE) as an antigen, and investigated the effects of various adjuvants (MF59, MF59/CpG 2006, and MF59/QS-21) on the immune response of C57BL/6J mice to find an alternative adjuvant to AS01B-like adjuvant of liposome/QS-21/MPL. In addition to safety, the gE-specific antibody, IgG antibody subtype, and cytokine secretion by splenocytes, and cell-mediated immune responses were determined using ELISA and ELISPOT assays, respectively. Our results showed no significant effects on the body weight, temperature, or behavior of mice vaccinated with PBS or all adjuvanted vaccines. All adjuvanted vaccine groups showed significantly higher gE-specific IgG antibody levels than the gE-alone group on day 28 after the first vaccine dose. In addition, all adjuvants induced a remarkable increase in both IgG1 and IgG2b levels. However, MF59/QS-21 and MF59/CpG 2006 showed comparable capacities to those of liposome/QS-21/MPL in increasing the IgG2c levels, being superior to MF59. Further investigation revealed that MF59 only induced a limited increase in the levels of Th1 and Th2 cytokines, while MF59/QS-21, MF59/CpG 2006, and liposome/QS-21/MPL led to a significant increase in the secretion of interferon gamma (IFN-γ), IL-2, IL-4, and IL-10 and showed a Th1-biased immune response. Moreover, MF59/QS-21, MF59/CpG 2006, and liposome/QS-21/MPL adjuvanted vaccines resulted in comparable gE-specific IFN-γ + immune cell responses. These results suggest that the combination of MF59 with QS-21 or CpG 2006 may be a promising adjuvant candidate for subunit HZ vaccines. Further investigations are needed to illustrate their durability and efficacy in aged mice.

Potential public health impact of the adjuvanted recombinant zoster vaccine among people aged 50 years and older in Beijing

Herpes zoster (HZ) is a painful, unilateral rash which occurs upon reactivation of latent varicella zoster virus due to age-related immunity decline or immuno-suppression. In 2019, the recombinant zoster vaccine (RZV) was the first vaccine to be approved in China for HZ prevention. This study aimed to estimate the potential public health impact of RZV vaccination, compared with the status quo of no vaccination, in individuals ≥50 years of age (YOA) in Beijing, by adapting the published ZOster ecoNomic Analysis (ZONA) model. We considered 5% and 50% vaccination coverage for the private market (near-term post-launch) and mass vaccination (long-term) settings respectively. In the base-case analysis of both market settings, second-dose compliance was set to 80%. Coverage and second-dose compliance rates were varied under scenario and sensitivity analyses. In the base case, mass vaccination with RZV was estimated to prevent 435,681 HZ cases, 51,558 postherpetic neuralgia (PHN) cases, and 15,703 cases of other HZ-related complications in the overall ≥50 YOA cohort over their remaining lifetime, compared with no vaccination. Under the same base-case scenario, 14,247 hospitalizations and 1,031,387 outpatient visits could be avoided. The 50-59 YOA cohort had the highest contributions to the overall reduction in HZ cases, its complications and related healthcare resource utilization. Results were robust under numerous scenario and sensitivity analyses. This analysis demonstrates the potential of RZV vaccination to substantially reduce the public health burden of HZ among individuals ≥50 YOA, and may inform appropriate vaccination strategies for HZ prevention, particularly in urban settings within China.

Safety and immunogenicity of adjuvanted recombinant subunit herpes zoster vaccine in lung transplant recipients

Lung transplant recipients are at high risk for herpes zoster and preventive measures are a significant unmet need. We investigated the safety and immunogenicity of two doses of a recombinant zoster vaccine (RZV) in lung transplant recipients (≥50 years). We enrolled 50 patients of which 49 received at least one vaccine dose. Anti-glycoprotein E (gE) antibody levels (n = 43) increased significantly compared to baseline (median optical density [OD] 1.96; interquartile range [IQR]: 1.17-2.89) after the first (median OD 3.41, IQR 2.54-3.81, p < .0001) and second vaccine dose (median OD 3.63, IQR 3.39-3.86, p < .0001). gE-specific polyfunctional CD4+ T cell frequencies (n = 38) also increased from baseline (median 85 per 10⁶ CD4+ T cells; IQR: 46-180) to the first (median 128 per 10⁶ CD4+ T cells; IQR: 82-353; p = .023) and after the second dose (median 361 per 10⁶ CD4+ T cells; IQR: 146-848; p < .0001). Tenderness (83.0%; 95%CI: 69.2-92.4%) and redness (31.9%; 95%CI: 19.1-47.1%) at injection site were common. One rejection episode within 3 weeks of vaccination was observed. This is the first study demonstrating that RZV was safe and elicited significant humoral and cell-mediated immunity in lung transplant recipients. RZV is a new option for the prevention of shingles in this population.

Comparative Antibody Responses to the Live-Attenuated and Recombinant Herpes Zoster Vaccines

Two herpes zoster (HZ) vaccines licensed in the United States are recommended by the Advisory Committee on Immunization Practices (ACIP): (i) live-attenuated vaccine (ZVL) using vOka strain varicella-zoster virus (VZV) and (ii) recombinant adjuvanted vaccine (RZV) containing recombinant varicella-zoster virus (VZV) glycoprotein E (gE). Two phase 3 clinical trials of RZV led the Advisory Committee on Immunization Practices (ACIP) to recommend it with preferred status. VZV T cell-mediated immunity (CMI), but not humoral immunity, is considered essential for protection against HZ. Published studies of humoral immunity focused on VZV-specific IgG concentration. To complement reports comparing the CMI responses to these vaccines, we compared humoral responses in ZVL and RZV recipients, emphasizing functional qualities (avidity and neutralization). Baseline avidities to a VZV glycoprotein mixture (gp) were near the upper limit of detection, but avidity to gE was much lower. Small increases in gp avidity were observed for both RZV and ZVL vaccination (19 and 12 avidity index units [AIU], respectively). RZV boosted both gE avidity and VZV neutralizing antibody significantly more than ZVL (mean gE avidity boost, 47 AIU versus 22 AIU; mean neutralizing antibody boost, 22-fold versus 8-fold). Increases in neutralizing antibodies strongly correlated with gE avidity increases (r = 0.5) and moderately with gp avidity increases (r = 0.23). After 1 year, 81% of RZV recipients and only 18% of ZVL recipients retained >50% of their peak avidity boosts. These results are consistent with the CMI responses to these vaccines: RZV responses are skewed to long-term memory, whereas ZVL preferentially induces transient effector responses.IMPORTANCE These observations further distinguish the immunogenicity and duration of the immune response of the two vaccines. In addition, measurements of functional humoral immunity (IgG avidity and neutralizing antibody) in response to zoster immunization, alone or combined with other immune markers, might contribute to practical in vitro correlates of protection. Combined with previous observations of the cell-mediated response to these vaccines, this study suggests that vaccine development will benefit from more expansive and granular assessments of acquired immunity during early phase 1 immunogenicity trials.

Antibody avidity, persistence, and response to antigen recall: comparison of vaccine adjuvants

Differences in innate immune ‘imprinting’ between vaccine adjuvants may mediate dissimilar effects on the quantity/quality of persisting adaptive responses. We compared antibody avidity maturation, antibody/memory B cell/CD4⁺ T cell response durability, and recall responses to non-adjuvanted fractional-dose antigen administered 1-year post-immunization (Day [D]360), between hepatitis B vaccines containing Adjuvant System (AS)01_B, AS01_E, AS03, AS04, or Alum (NCT00805389). Both the antibody and B cell levels ranked similarly (AS01_B/E/AS03 > AS04 > Alum) at peak response, at D360, and following their increases post-antigen recall (D390). Proportions of high-avidity antibodies increased post-dose 2 across all groups and persisted at D360, but avidity maturation appeared to be more strongly promoted by AS vs. Alum. Post-antigen recall, frequencies of subjects with high-avidity antibodies increased only markedly in the AS groups. Among the AS, total antibody responses were lowest for AS04. However, proportions of high-avidity antibodies were similar between groups, suggesting that MPL in AS04 contributes to avidity maturation. Specific combinations of immunoenhancers in the AS, regardless of their individual nature, increase antibody persistence and avidity maturation.

Aging and Options to Halt Declining Immunity to Virus Infections

Immunosenescence is a process associated with aging that leads to dysregulation of cells of innate and adaptive immunity, which may become dysfunctional. Consequently, older adults show increased severity of viral and bacterial infections and impaired responses to vaccinations. A better understanding of the process of immunosenescence will aid the development of novel strategies to boost the immune system in older adults. In this review, we focus on major alterations of the immune system triggered by aging, and address the effect of chronic viral infections, effectiveness of vaccination of older adults and strategies to improve immune function in this vulnerable age group.

Culture media optimization for Chinese hamster ovary cell growth and expression of recombinant varicella-zoster virus glycoprotein E

Herpes zoster (HZ) is caused by reactivation of varicella-zoster virus (VZV) latent in the sensory ganglia and causes severe pain, often leading to postherpetic neuralgia (PHN). Two prophylactic vaccines against HZ are currently licensed for human use, a live attenuated vaccine and a subunit vaccine containing recombinant VZV glycoprotein E (gE) as antigen. The latter has superior protective efficacy against HZ and PHN. During HZ subunit vaccine development, we obtained Chinese hamster ovary (CHO) cell clones expressing VZV gE. This study was performed to optimize culture media conditions for CHO cell growth and gE production. Using a high-throughput culture system, three CHO cell clones were cultured in microtiter plates containing 24 different basal media, and three basal media were selected. The clone with the highest gE expression was fed-batch cultured in each of the three basal media in combination with 13 different feed media. A pair of media, BalanCD CHO Growth A and EX-CELL Advanced CHO Feed 1, with the highest productivity was selected for gE production. Scale-up fed-batch cultures of the selected clone cultured in a wave bag bioreactor containing the optimized media yielded 2440 mg gE protein/L culture, a 11.5-fold increase compared to original culture conditions (batch culture in CD OptiCHO medium). The optimized media condition is used to produce VZV gE antigen for an HZ subunit vaccine, which is under phase I clinical trial. This study would provide valuable insights on culture media optimization for CHO cells expressing a recombinant vaccine antigen.

Early examination of real-world uptake and second-dose completion of recombinant zoster vaccine in the United States from October 2017 to September 2019

Shingrix (Recombinant zoster vaccine, RZV) was approved in October 2017 in the United States (US) for the prevention of herpes zoster in adults aged 50 years and older. The vaccine is administered in two doses, with the second dose administration recommended between two and six months after the first dose. Examination of uptake and series completion is important to ensure appropriate use, especially at the time of vaccine introduction. This report provides demographic characteristics of patients receiving RZV between October 2017 and September 2019, first- and second-dose uptake, and a cumulative estimation of second-dose completion by month for US adults aged 50 years and older. Monthly uptake increased rapidly since October 2017; overall, 7,097,441 first doses of RZV were administered along with 4,277,636 second doses during the observed timeframe. Among people with an observed first-dose administration, 70% and 80% completed the two-dose series within six and 12 months post initial dose, respectively. This evidence suggests that RZV has rapidly been adopted by a large population in the US and most are following manufacturer or policy recommendations regarding series completion. Further analyses are needed to explore potential patient, provider, and policy-relevant characteristics associated with second-dose completion that could serve as targets for further improvement.

Vaccines for older adults

The proportion of the global population aged 65 and older is rapidly increasing. Infections in this age group, most recently with SARS-CoV-2, cause substantial morbidity and mortality. Major improvements have been made in vaccines for older people, either through the addition of novel adjuvants-as in the new recombinant zoster vaccine and an adjuvanted influenza vaccine-or by increasing antigen concentration, as in influenza vaccines. In this article we review improvements in immunization for the three most important vaccine preventable diseases of aging. The recombinant zoster vaccine has an efficacy of 90% that is minimally affected by the age of the person being vaccinated and persists for more than four years. Increasing antigen dose or inclusion of adjuvant has improved the immunogenicity of influenza vaccines in older adults, although the relative effectiveness of the enhanced influenza vaccines and the durability of the immune response are the focus of ongoing clinical trials. Conjugate and polysaccharide pneumococcal vaccines have similar efficacy against invasive pneumococcal disease and pneumococcal pneumonia caused by vaccine serotypes in older adults. Their relative value varies by setting, depending on the prevalence of vaccine serotypes, largely related to conjugate vaccine coverage in children. Improved efficacy will increase public confidence and uptake of these vaccines. Co-administration of these vaccines is feasible and important for maximal uptake in older people. Development of new vaccine platforms has accelerated following the arrival of SARS-CoV-2, and will likely result in new vaccines against other pathogens in the future.

Influence of immune aging on vaccine responses

Impaired vaccine responses in older individuals are associated with alterations in both the quantity and quality of the T-cell compartment with age. As reviewed herein, the T-cell response to vaccination requires a fine balance between the generation of inflammatory effector T cells versus follicular helper T (T_FH) cells that mediate high-affinity antibody production in tandem with the induction of long-lived memory cells for effective recall immunity. During aging, we find that this balance is tipped where T cells favor short-lived effector but not memory or T_FH responses. Consistently, vaccine-induced antibodies commonly display a lower protective capacity. Mechanistically, multiple, potentially targetable, changes in T cells have been identified that contribute to these age-related defects, including posttranscription regulation, T-cell receptor signaling, and metabolic function. Although research into the induction of tissue-specific immunity by vaccines and with age is still limited, current mechanistic insights provide a framework for improved design of age-specific vaccination strategies that require further evaluation in a clinical setting.

COVID-19 Vaccination: From Interesting Agent to the Patient

The vaccination for the novel Coronavirus (COVID-19) is undergoing its final stages of analysis and testing. It is an impressive feat under the circumstances that we are on the verge of a potential breakthrough vaccination. This will help reduce the stress for millions of people around the globe, helping to restore worldwide normalcy. In this review, the analysis looks into how the new branch of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) came into the forefront of the world like a pandemic. This review will break down the details of what COVID-19 is, the viral family it belongs to and its background of how this family of viruses alters bodily functions by attacking vital human respiratory organs, the circulatory system, the central nervous system and the gastrointestinal tract. This review also looks at the process a new drug analogue undergoes, from (i) being a promising lead compound to (ii) being released into the market, from the drug development and discovery stage right through to FDA approval and aftermarket research. This review also addresses viable reasoning as to why the SARS-CoV-2 vaccine may have taken much less time than normal in order for it to be released for use.

Identification and Characterization of CD4+ T Cell Epitopes after Shingrix Vaccination

Infections with varicella-zoster virus (VZV) are associated with a range of clinical manifestations. Primary infection with VZV causes chicken pox. The virus remains latent in neurons, and it can reactivate later in life, causing herpes zoster (HZ). Two different vaccines have been developed to prevent HZ; one is based on a live attenuated VZV strain (Zostavax), and the other is based on adjuvanted gE recombinant protein (Shingrix). While Zostavax efficacy wanes with age, Shingrix protection retains its efficacy in elderly subjects (individuals 80 years of age and older). In this context, it is of much interest to understand if there is a role for T cell immunity in the differential clinical outcome and if there is a correlate of protection between T cell immunity and Shingrix efficacy. In this study, we characterized the Shingrix-specific ex vivo CD4 T cell responses in the context of natural exposure and HZ vaccination using pools of predicted epitopes. We show that T cell reactivity following natural infection and Zostavax vaccination dominantly targets nonstructural (NS) proteins, while Shingrix vaccination redirects dominant reactivity to target gE. We mapped the gE-specific responses following Shingrix vaccination to 89 different gE epitopes, 34 of which accounted for 80% of the response. Using antigen presentation assays and single HLA molecule-transfected lines, we experimentally determined HLA restrictions for 94 different donor/peptide combinations. Finally, we used our results as a training set to assess strategies to predict restrictions based on measured or predicted HLA binding and the corresponding HLA types of the responding subjects.IMPORTANCE Understanding the T cell profile associated with the protection observed in elderly vaccinees following Shingrix vaccination is relevant to the general definition of correlates of vaccine efficacy. Our study enables these future studies by clarifying the patterns of immunodominance associated with Shingrix vaccination, as opposed to natural infection or Zostavax vaccination. Identification of epitopes recognized by Shingrix-induced CD4 T cells and their associated HLA restrictions enables the generation of tetrameric staining reagents and, more broadly, the capability to characterize the specificity, magnitude, and phenotype of VZV-specific T cells.

Potential adjuvants for the development of a SARS-CoV-2 vaccine based on experimental results from similar coronaviruses

The extensive efforts around the globe are being made to develop a suitable vaccine against COVID-19 (Coronavirus Disease-19) caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus-2). An effective vaccine should be able to induce high titers of neutralizing antibodies to prevent the virus from attaching to the host cell receptors. However, to elicit the protective levels of antibodies, a vaccine may require multiple doses or assistance from other immunostimulatory molecules. Further, the vaccine should be able to induce protective levels of antibodies rapidly with the least amount of antigen used. This decreases the cost of a vaccine and makes it affordable. As the pandemic has hit most countries across the globe, there will be an overwhelming demand for the vaccine in a quick time. Incorporating a suitable adjuvant in a SARS-CoV-2 vaccine may address these requirements. This review paper will discuss the experimental results of the adjuvanted vaccine studies with similar coronaviruses (CoVs) which might be useful to select an appropriate adjuvant for a vaccine against rapidly emergingSARS-CoV-2. We also discuss the current progress in the development of adjuvanted vaccines against the disease.

Immunogenicity of the adjuvanted recombinant zoster vaccine: persistence and anamnestic response to additional doses administered 10 years after primary vaccination

Background

The adjuvanted recombinant zoster vaccine (RZV) is highly immunogenic and efficacious in adults ≥50 years of age. We evaluated (1) long-term immunogenicity of an initial 2-dose RZV schedule, by following up adults vaccinated at ≥60 years of age and by modeling, and (2) immunogenicity of 2 additional doses administered 10 years after initial vaccination.

Methods

Persistence of humoral and cell-mediated immune (CMI) responses to 2 initial RZV doses was assessed through 10 years after initial vaccination, and modeled through 20 years using a Piecewise, Power law and Fraser model. The immunogenicity and safety of 2 additional RZV doses were also evaluated.

Results

Seventy adults were enrolled. Ten years after initial vaccination, humoral and CMI responses were approximately 6-fold and 3.5-fold, respectively, above those before the initial vaccination levels. Predicted immune persistence through 20 years after initial vaccination was similar across the 3 models. Sixty-two participants (mean age [standard deviation], 82.6 [4.4] years) received ≥1 additional RZV dose. Strong anamnestic humoral and CMI responses were elicited by 1 additional dose, without further increases after a second additional dose.

Conclusions

Immune responses to an initial 2-dose RZV course persisted for many years in older adults. Strong anamnestic immune responses can be induced by additional dosing 10 years after the initial 2-dose course.

Clinical Trials Registration

NCT02735915.

[S2k guideline for the diagnosis and therapy of zoster and post-zoster neuralgia]

Diese Leitlinie richtet sich an Dermatologen, Ophthalmologen, HNO-Ärzte, Pädiater, Neurologen, Virologen sowie Infektiologen, Anästhesisten und Allgemeinmediziner in Klinik und Praxis und dient zur Information für andere medizinische Fachrichtungen, die an der Behandlung des Zoster beteiligt sind. Darüber hinaus soll die Leitlinie Kostenträgern und politischen Entscheidungsträgern zur Orientierung dienen. Die Leitlinie wurde im formellen Konsensusverfahren (S2k) von Dermatologen, Virologen/Infektiologen, Ophthalmologen, HNO-Ärzten, Neurologen, Pädiatern und Anästhesisten/Schmerzmedizinern erstellt.

Die Leitlinie stellt einen Überblick über die klinische und molekulare Diagnostik sowie den Antigennachweis, die Antikörperkultur und Viruskultur dar. Diagnostisch besondere Situationen und komplizierte Verläufe der Erkrankung finden ebenfalls Berücksichtigung. Die antivirale Therapie des Zoster und der Postzosterneuralgie wird im Allgemeinen und für besondere Situationen dargelegt. Detaillierte Angaben zur Schmerzbehandlung finden Erwähnung und sind in einer Übersicht dargestellt. Ebenso werden die lokaltherapeutischen Maßnahmen thematisiert.

Successful Vaccines

Vaccines are considered one of the most important advances in modern medicine and have greatly improved our quality of life by reducing or eliminating many serious infectious diseases. Successful vaccines have been developed against many of the most common human pathogens, and this success has not been dependent upon any one specific class of vaccine since subunit vaccines, non-replicating whole-virus or whole-bacteria vaccines, and attenuated live vaccines have all been effective for particular vaccine targets. After completing the initial immunization series, one common aspect of successful vaccines is that they induce long-term protective immunity. In contrast, several partially successful vaccines appear to induce protection that is relatively short-lived and it is likely that long-term protective immunity will be critical for making effective vaccines against our most challenging diseases such as AIDS and malaria.

Treatment Patterns and Medication Use in Patients with Postherpetic Neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is a chronic, painful condition characterized by persistent pain following resolution of a herpes zoster (HZ) infection. Epidemiologic data demonstrate that the risks for HZ infections and the development of PHN increase with age.

OBJECTIVE

To characterize prescribing patterns, health care utilization, and treatment costs for adults with PHN based on real-world data.

METHODS

This study analyzed medical and pharmacy claims from 2010 to 2014 in the MarketScan Commercial and Medicare Supplemental databases. PHN patients were identified based on criteria from a published algorithm. PHN treatment patterns were analyzed by age and reported descriptively for patients aged < 65 or ≥ 65 years. Excess incremental health care costs were calculated for PHN patients by comparing expenditures for a cohort of PHN patients to expenditures of a propensity score-matched control group of patients with HZ alone.

RESULTS

Approximately 0.4% of patients aged < 65 years were diagnosed with HZ versus 1.3% of patients aged ≥ 65 years; approximately 15.3% of HZ patients aged < 65 years and 26.4% of patients aged ≥ 65 years were diagnosed with PHN. Overall, opioids remained the most frequently prescribed initial treatment. Approximately 21.6% of PHN patients received an opioid as an initial treatment for PHN, 15.1% received gabapentin; 8.9% received a prescription nonsteroidal anti-inflammatory drug (NSAID); 8.3% received a lidocaine patch; 3.3% received pregabalin; 2.5% received a tricyclic antidepressants (TCAs); 0.8% received other topical lidocaine; and < 1% received capsaicin. Observed first-line use of the lidocaine patch and gabapentin was higher in patients aged ≥ 65 years relative to patients aged < 65 years. When separated by age group, only 24.6% of patients aged < 65 years and 38.5% of patients aged ≥ 65 years were prescribed a recommended first-line treatment for initial PHN therapy (gabapentin, lidocaine patch, pregabalin, and TCAs). Comparisons of treatment costs of PHN patients to matched HZ patients without PHN indicated that PHN patients initiated on opioids had the highest mean additional health care expenditure compared with PHN patients initiated on other medications. On average, PHN patients initiated on opioids had $7,601 additional health care expenditure compared with HZ patients with no PHN; additional expenditures were $6,428 for pregabalin, $4,213 for lidocaine patches, $3,478 for gabapentin, $3,304 for NSAIDs, and $2,797 for TCAs, respectively.

CONCLUSIONS

Management of PHN is associated with substantial utilization of opioid-based therapies across all ages. Medications supported by evidence either as first-line therapies or as part of a multimodal regimen for the management of PHN are underused relative to opioid-based PHN therapies. Improving adherence to evidence-based PHN treatment regimens offers the potential to reduce opioid prescribing first line and reduce overall treatment costs. Given the emphasis to reduce opioid prescribing to minimize the risk of dependence, abuse, and diversion, multimodal analgesic treatments that can avoid or reduce opioid use should be considered.

DISCLOSURES

Research funding was provided by SCILEX Pharmaceuticals. The sponsor reviewed and approved the research plan and provided support for manuscript preparation through Patel's role as a coauthor of this manuscript. The sponsor's product (lidocaine patch) was not used in this study. Patel is a paid employee of SCILEX Pharmaceuticals. Goss is an employee and minority owner of Boston Healthcare Associates, which received a research grant from SCILEX Pharmaceuticals to conduct this study. Gudin reports advisory board fees from AcelRx Pharmaceuticals and BioDelivery Sciences International and consulting fees from Averitas, Daiichi, Hisumitsu, Nektar, Purdue, Quest Diagnostics, SCILEX Pharmaceuticals, and US WorldMeds, unrelated to this study. Fudin reports advisory board fees from AcelRx Pharmaceuticals, Human Half-Cell, Quest Diagnostics, GlaxoSmithKline, SCILEX Pharmaceuticals, BioDelivery Sciences, Daiichi Sankyo, and Salix Pharmaceuticals; speaker fees from Daiichi Sankyo, Salix Pharmaceuticals, Abbott Laboratories, Acutis Diagnostics, and AstraZeneca; and consulting fees from Firstox Laboratories, unrelated to this study. The other authors have nothing to disclose. Parts of this research were presented at the AMCP Managed Care & Specialty Pharmacy Annual Meeting; April 22, 2016; San Francisco, CA, and at the 35th Annual Scientific Meeting of the American Pain Society; May 11-14, 2016; Austin, TX.

Adjuvanted Recombinant Glycoprotein E Herpes Zoster Vaccine

The adjuvanted recombinant glycoprotein E herpes zoster (HZ) vaccine is superior to the live attenuated HZ vaccine, with an efficacy >90% against HZ in healthy immunocompetent adults aged ≥50 years after vaccination. In pivotal studies, the efficacy of the new vaccine varied very little with the age of the vaccinee and decreased only by 5-10% in the 3.5 years after immunization. This nonlive vaccine was successfully administered to small cohorts of immunocompromised individuals; initial trials showed efficacy of >60-80% in several such settings. Potential drawbacks include the requirement for 2 vaccine doses separated by 2-6 months, local and systemic reactogenicity that is significantly greater than observed with commonly used vaccines, and the inclusion of a strong adjuvant that has been minimally studied in clinical settings where it might be problematic, such as in people with autoimmune diseases. Postmarketing studies are underway to address some of the drawbacks.

Public Health Impact and Cost-Effectiveness of Non-live Adjuvanted Recombinant Zoster Vaccine in Canadian Adults

OBJECTIVES

In Canada, incidences of herpes zoster (HZ) and postherpetic neuralgia (PHN) are increasing, posing a significant burden on the healthcare system. This study aimed to determine the public health impact and cost effectiveness of an adjuvanted recombinant zoster vaccine (RZV) compared to no vaccination and to the live attenuated vaccine (ZVL) in Canadians aged 60 years and older.

METHODS

A multi-cohort Markov model has been adapted to the Canadian context using recent demographic and epidemiologic data. Simulations consisted of age-cohorts annually transitioning between health states. Health outcomes and costs were discounted at 1.5% per year. The perspective of the Canadian healthcare payer was adopted. A coverage of 80% for the first RZV and ZVL dose and a compliance of 75% for the second RZV dose were assumed.

RESULTS

RZV was estimated to be cost effective compared with no vaccination with an incremental cost-effectiveness ratio (ICER) of $28,360 (Canadian dollars) per quality-adjusted life-year (QALY) in persons aged ≥ 60 years, avoiding 554,504 HZ and 166,196 PHN cases. Compared with ZVL, RZV accrued more QALYs through the remaining lifetime and an increase in costs of approximately $50 million resulting in an average ICER of $2396. Results were robust under deterministic and probabilistic sensitivity analyses. HZ incidence rate and persistence of vaccine efficacy had the largest impact on cost effectiveness.

CONCLUSIONS

The cost-utility analysis suggested that RZV would be cost effective in the Canadian population compared with no vaccination and vaccination with ZVL at a willingness-to-pay threshold of $50,000.

Immunosenescence and human vaccine immune responses

The age-related dysregulation and decline of the immune system-collectively termed "immunosenescence"-has been generally associated with an increased susceptibility to infectious pathogens and poor vaccine responses in older adults. While numerous studies have reported on the clinical outcomes of infected or vaccinated individuals, our understanding of the mechanisms governing the onset of immunosenescence and its effects on adaptive immunity remains incomplete. Age-dependent differences in T and B lymphocyte populations and functions have been well-defined, yet studies that demonstrate direct associations between immune cell function and clinical outcomes in older individuals are lacking. Despite these knowledge gaps, research has progressed in the development of vaccine and adjuvant formulations tailored for older adults in order to boost protective immunity and overcome immunosenescence. In this review, we will discuss the development of vaccines for older adults in light of our current understanding-or lack thereof-of the aging immune system. We highlight the functional changes that are known to occur in the adaptive immune system with age, followed by a discussion of current, clinically relevant pathogens that disproportionately affect older adults and are the central focus of vaccine research efforts for the aging population. We conclude with an outlook on personalized vaccine development for older adults and areas in need of further study in order to improve our fundamental understanding of adaptive immunosenescence.

Comparative Immune Responses to Licensed Herpes Zoster Vaccines

Background

Live attenuated (ZV) and recombinant adjuvanted (HZ/su) zoster vaccines differ with respect to efficacy, effect of age, and persistence of protection. We compared cell-mediated immunity (CMI responses to ZV and HZ/su.

Methods

This was a randomized, double-blind, placebo-controlled trial stratified by age (50-59 and 70-85 years) and by HZ vaccination status (received ZV ≥5 years before entry or not). Varicella zoster virus (VZV)- and glycoprotein E (gE)-specific CMI were analyzed by interleukin 2 (IL-2) and interferon gamma (IFN-γ) FluoroSpot and flow cytometry at study days 0, 30, 90, and 365.

Results

Responses to ZV peaked on day 30 and to HZ/su (administered in 2 doses separated by 60 days) peaked on day 90. Age and vaccination status did not affect peak responses, but higher baseline CMI correlated with higher peak responses. HZ/su generated significantly higher VZV-specific IL-2+ and gE-specific IL-2+, IFN-γ+, and IL-2+/IFN-γ+ peak and 1-year baseline-adjusted responses compared with ZV. VZV-specific IFN-γ+ and IL-2+/IFN-γ+ did not differ between vaccines. HZ/su generated higher memory and effector-memory CD4+ peak responses and ZV generated higher effector CD4+ responses .

Conclusions

The higher IL-2 and other memory responses generated by HZ/su compared with ZV may contribute to its superior efficacy.

Clinical Trials Registration

NCT02114333.

Herpes Zoster Vaccines

Background

Immunization for herpes zoster (HZ) aims to reverse the decline in cell-mediated immunity to varicella zoster virus that occurs with advancing age or immunocompromise. There are 2 vaccines available, one live attenuated (Zoster vaccine, live attenuated [ZVL]) and, recently, a recombinant subunit vaccine (HZ/su).

Methods

The literature relevant to the two HZ vaccines was reviewed.

Results

ZVL has overall efficacies of 51% and 65% against HZ and postherpetic neuralgia, respectively, with a prominent decline in efficacy with advancing age of the vaccinee. This compares to approximately 90% efficacy against HZ for HZ/su that is minimally affected with advancing age. The efficacy of ZVL against HZ declines over 4 and 8 years, compared with minimal decline so far over 4 years with HZ/su, and immunogenicity that is maintained for 9 years. Local and systemic reactogenicity to HZ/su is much greater than to ZVL.

Conclusions

HZ/su establishes an important principle-that a single recombinant viral protein with an effective adjuvant combination can stimulate immunogenicity superior to that of a live attenuated vaccine, and that this can diminish immunosenescence. This provides hope for improvement of other vaccines for aging patients. However, key questions remain unanswered, including the durability of the efficacy of HZ/su, its efficacy as a booster for previous recipients of ZVL, and its efficacy in immunocompromised patients.

Immune Responses to a Recombinant Glycoprotein E Herpes Zoster Vaccine in Adults Aged 50 Years or Older

Background

The herpes zoster subunit vaccine (HZ/su), consisting of varicella-zoster virus glycoprotein E (gE) and AS01_B Adjuvant System, was highly efficacious in preventing herpes zoster in the ZOE-50 and ZOE-70 trials. We present immunogenicity results from those trials.

Methods

Participants (ZOE-50: ≥50; ZOE-70: ≥70 years of age) received 2 doses of HZ/su or placebo, 2 months apart. Serum anti-gE antibodies and CD4 T cells expressing ≥2 of 4 activation markers assessed (CD4²⁺) after stimulation with gE-peptides were measured in subcohorts for humoral (n = 3293) and cell-mediated (n = 466) immunogenicity.

Results

After vaccination, 97.8% of HZ/su and 2.0% of placebo recipients showed a humoral response. Geometric mean anti-gE antibody concentrations increased 39.1-fold and 8.3-fold over baseline in HZ/su recipients at 1 and 36 months post-dose 2, respectively. A gE-specific CD4²⁺ T-cell response was shown in 93.3% of HZ/su and 0% of placebo recipients. Median CD4²⁺ T-cell frequencies increased 24.6-fold (1 month) and 7.9-fold (36 months) over baseline in HZ/su recipients and remained ≥5.6-fold above baseline in all age groups at 36 months. The proportion of CD4 T cells expressing all 4 activation markers increased over time in all age groups.

Conclusions

Most HZ/su recipients developed robust immune responses persisting for 3 years following vaccination.

Clinical Trials Registration

NCT01165177; NCT01165229.

Varicella zoster virus vaccines: an update

Varicella zoster virus (VZV) is the etiological agent of varicella, a highly infectious, self-limiting disease with serious complications. The decline in cell-mediated immunity (CMI) that occurs with aging or immunodepression causes a reactivation of the latent VZV as herpes zoster (HZ). Prevention of VZV through varicella vaccination strategies allows to avoid the primary infection in newborns and susceptible subjects. Available monovalent and combined VZV vaccines are effective, safe and generally well tolerated. Universal varicella vaccination has significantly impacted on incidence, complications and deaths related to this disease. Prevention of HZ through vaccination is a priority to avoid the significant burden of its incidence and complications. Currently two HZ vaccines are available. The recombinant zoster vaccine (RZV), approved by the FDA in 2017 and Zoster Vaccine Live (ZVL) licensed in the United States by the FDA in 2006. The advisory committee on immunization practices (ACIP) preferentially recommends RZV. ZVL remains an option for prevention of HZ in immunocompetent adults aged ≥60 years, although the CMI tends to wane a few years after vaccination.

Effect of Recombinant Zoster Vaccine on Incidence of Herpes Zoster After Autologous Stem Cell Transplantation: A Randomized Clinical Trial

IMPORTANCE

Herpes zoster, a frequent complication following autologous hematopoietic stem cell transplantation (HSCT), is associated with significant morbidity. A nonlive adjuvanted recombinant zoster vaccine has been developed to prevent posttransplantation zoster.

OBJECTIVE

To assess the efficacy and adverse event profile of the recombinant zoster vaccine in immunocompromised autologous HSCT recipients.

DESIGN, SETTING, AND PARTICIPANTS

Phase 3, randomized, observer-blinded study conducted in 167 centers in 28 countries between July 13, 2012, and February 1, 2017, among 1846 patients aged 18 years or older who had undergone recent autologous HSCT.

INTERVENTIONS

Participants were randomized to receive 2 doses of either recombinant zoster vaccine (n = 922) or placebo (n = 924) administered into the deltoid muscle; the first dose was given 50 to 70 days after transplantation and the second dose 1 to 2 months thereafter.

MAIN OUTCOMES AND MEASURES

The primary end point was occurrence of confirmed herpes zoster cases.

RESULTS

Among 1846 autologous HSCT recipients (mean age, 55 years; 688 [37%] women) who received 1 vaccine or placebo dose, 1735 (94%) received a second dose and 1366 (74%) completed the study. During the 21-month median follow-up, at least 1 herpes zoster episode was confirmed in 49 vaccine and 135 placebo recipients (incidence, 30 and 94 per 1000 person-years, respectively), an incidence rate ratio (IRR) of 0.32 (95% CI, 0.22-0.44; P < .001), equivalent to 68.2% vaccine efficacy. Of 8 secondary end points, 3 showed significant reductions in incidence of postherpetic neuralgia (vaccine, n=1; placebo, n=9; IRR, 0.1; 95% CI, 0.00-0.78; P = .02) and of other prespecified herpes zoster-related complications (vaccine, n=3; placebo, n=13; IRR, 0.22; 95% CI, 0.04-0.81; P = .02) and in duration of severe worst herpes zoster-associated pain (vaccine, 892.0 days; placebo, 6275.0 days; hazard ratio, 0.62; 95% CI, 0.42-0.89; P = .01). Five secondary objectives were descriptive. Injection site reactions were recorded in 86% of vaccine and 10% of placebo recipients, of which pain was the most common, occurring in 84% of vaccine recipients (grade 3: 11%). Unsolicited and serious adverse events, potentially immune-mediated diseases, and underlying disease relapses were similar between groups at all time points.

CONCLUSIONS AND RELEVANCE

Among adults who had undergone autologous HSCT, a 2-dose course of recombinant zoster vaccine compared with placebo significantly reduced the incidence of herpes zoster over a median follow-up of 21 months.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01610414.

Updated insights into the mechanism of action and clinical profile of the immunoadjuvant QS-21: A review

BACKGROUND

Vaccine adjuvants are compounds that significantly enhance/prolong the immune response to a co-administered antigen. The limitations of the use of aluminium salts that are unable to elicite cell responses against intracellular pathogens such as those causing malaria, tuberculosis, or AIDS, have driven the development of new alternative adjuvants such as QS-21, a triterpene saponin purified from Quillaja saponaria.

PURPOSE

The aim of this review is to attempt to clarify the mechanism of action of QS-21 through either receptors or signaling pathways in vitro and in vivo with special emphasis on the co-administration with other immunostimulants in new adjuvant formulations, called adjuvant systems (AS). Furthermore, the most relevant clinical applications will be presented.

METHODS

A literature search covering the period 2014-2018 was performed using electronic databases from Sci finder, Science direct, Medline/Pubmed, Scopus, Google scholar.

RESULTS

Insights into the mechanism of action of QS-21 can be summarized as follows: 1) in vivo stimulation of Th2 humoral and Th1 cell-mediated immune responses through action on antigen presenting cells (APCs) and T cells, leading to release of Th1 cytokines participating in the elimination of intracellular pathogens. 2) activation of the NLRP3 inflammasome in mouse APCs with subsequent release of caspase-1 dependent cytokines, Il-1β and Il-18, important for Th1 responses. 3) synthesis of nearly 50 QS-21 analogs, allowing structure/activity relationships and mechanistic studies. 4) unique synergy mechanism between monophosphoryl lipid A (MPL A) and QS-21, formulated in a liposome (AS01) in the early IFN-γ response, promoting vaccine immunogenicity. The second part of the review is related to phase I-III clinical trials of QS-21, mostly formulated in ASs, to evaluate efficacy, immunogenicity and safety of adjuvanted prophylactic vaccines against infectious diseases, e.g. malaria, herpes zoster, tuberculosis, AIDS and therapeutic vaccines against cancer and Alzheimer's disease.

CONCLUSION

The most advanced phase III clinical applications led to the development of two vaccines containing QS-21 as part of the AS, the Herpes Zoster vaccine (HZ/su) (Shingrix™) which received a license in 2017 from the FDA and a marketing authorization in the EU in 2018 and the RTS,S/AS01 vaccine (Mosquirix™) against malaria, which was approved by the EMA in 2015 for further implementation in Sub-Saharan countries for routine use.

Public health impact model estimating the impact of introducing an adjuvanted recombinant zoster vaccine into the UK universal mass vaccination programme

OBJECTIVES

In 2013, the herpes zoster (HZ) immunisation programme was introduced in the UK, recommending vaccination of adults 70 years of age (YOA) with the zoster vaccine live (ZVL), the only vaccine available at the time. The recently approved adjuvanted recombinant zoster vaccine (RZV) has a substantially different clinical profile that may offer additional benefits.This study aimed to 1) assess the public health impact (PHI) of introducing RZV in the UK compared with the current vaccination strategy and 2) explore via scenario analyses the optimal age group of vaccination in terms of PHI.

DESIGN

A previously developed health economic model was adapted to the UK setting.

SETTING

Calculations were based on efficacy data from pivotal clinical trials, HZ incidence and postherpetic neuralgia (PHN) probability from a UK study and HZ-associated complication rates from published literature.

POPULATION

The base-case population considered a 2018-projected UK vaccination cohort of individuals 70 YOA.

INTERVENTIONS

Vaccination with ZVL or RZV, assuming a first-dose coverage of 48.3% for both vaccines and 70% compliance for the second dose of RZV.

OUTCOME MEASURES

Outcomes included reduction of HZ and PHN cases, complications and the use of healthcare resources over a life-time horizon. The impact of coverage and second-dose compliance was also explored.

RESULTS

Compared with no vaccination, RZV would lead to a reduction of 30 262 HZ and 5409 PHN cases while ZVL would lead to a reduction of 7909 HZ and 3567 PHN cases. The number needed to vaccinate to prevent 1 HZ case is 12 with RZV and 45 with ZVL. The highest PHI with RZV could be achieved in individuals 60 or 65 YOA.

CONCLUSION

Under the model assumptions, RZV is predicted to avert more HZ and PHN cases compared with ZVL. Results were robust under different scenario and sensitivity analyses.

Immunogenicity and safety of the adjuvanted recombinant zoster vaccine in patients with solid tumors, vaccinated before or during chemotherapy: A randomized trial

BACKGROUND

The adjuvanted recombinant zoster vaccine (RZV) has demonstrated >90% efficacy against herpes zoster in adults ≥50 years of age and 68% efficacy in autologous hematopoietic stem cell transplant recipients ≥18 years of age. We report the immunogenicity and safety of RZV administered to patients with solid tumors (STs) before or at the start of a chemotherapy cycle.

METHOD

In this phase 2/3 observer-blind, multicenter study (NCT01798056), patients with STs who were ≥18 years of age were randomized (1:1) to receive 2 doses of RZV or placebo 1-2 months apart and stratified (4:1) according to the timing of the first dose with respect to the start of a chemotherapy cycle (first vaccination 8-30 days before the start or at the start [±1 day] of a chemotherapy cycle). Anti-glycoprotein E (gE) antibody concentrations, gE-specific CD4+ T cell frequencies, and vaccine response rates (VRRs) were assessed 1 month after dose 1 and 1 and 12 months after dose 2. Reactogenicity and safety were assessed in the total vaccinated cohort through 12 months after dose 2.

RESULTS

There were 232 participants in the total vaccinated cohort, 185 participants in the according-to-protocol cohort for humoral immunogenicity, and 58 participants in the according-to-protocol cohort for cell-mediated immunogenicity. Postvaccination anti-gE antibody concentrations, gE-specific CD4+ T cell frequencies and VRRs were higher in RZV recipients than in placebo recipients. Solicited adverse events (AEs) were more frequent among RZV recipients than placebo recipients. Incidence of unsolicited AEs, serious AEs, fatalities, and potential immune-mediated diseases were similar between RZV and placebo recipients.

CONCLUSION

RZV was immunogenic in patients with STs receiving immunosuppressive chemotherapies. Humoral and cell-mediated immune responses persisted 1 year after vaccination. No safety concerns were identified.

Cost-Effectiveness of the Adjuvant Recombinant Zoster Vaccine in Japanese Adults Aged 65 Years and Older

INTRODUCTION

The incidence of herpes zoster (HZ) rises steeply after the age of 50 years and the number of HZ cases and complications such as postherpetic neuralgia (PHN) is predicted to increase because of the ageing population. The objective of this study was to estimate the cost-effectiveness of recombinant zoster vaccine (RZV) compared with no vaccine for the Japanese population aged ≥ 65 years.

METHODS

A multi-cohort static Markov model with a cycle length of 1 year was used to follow a hypothetical cohort of 1 million people aged ≥ 65 years over their remaining lifetime. Vaccination at ≥ 65 years was used in alignment with the influenza and pneumococcal vaccines recommended from 65 years. Japan-specific data inputs for the model were obtained from local data sources. Age-stratified vaccine efficacy and waning rates were based on published clinical trial data. In the base-case analysis, vaccine coverage was assumed to be 40% with a second dose compliance of 95%. Costs and outcomes were discounted at 2% annually and the incremental cost-effectiveness ratio (ICER) was calculated from both a payer's and the societal perspective. Sensitivity analyses were carried out to explore the overall uncertainty in the model.

RESULTS

Vaccination with RZV was projected to prevent 48,943 HZ cases and 12,136 PHN cases per million people aged ≥ 65 years compared with no vaccination. The incremental costs and quality-adjusted life years (QALYs) gained were ¥9.99 billion and 2314 QALYs from a payer's perspective and ¥9.34 billion and 2314 QALYs from a societal perspective. The resulting ICERs were approximately ¥4,320,000 and ¥4,040,000 per QALY gained from a payer's and the societal perspective, respectively. The ICER remained below a willingness-to-pay threshold of ¥5,000,000 for most sensitivity analyses carried out.

CONCLUSION

Vaccination against HZ with RZV would be cost-effective compared with no vaccination for the Japanese population aged ≥ 65 years.

TRIAL REGISTRATION

GSK study identifier: HO-16-17837.

FUNDING

GlaxoSmithKline Biologicals SA.

Immune responses to zoster vaccines

There are two licensed herpes zoster vaccines. One is a live vaccine (ZVL) based on an attenuated varicella-zoster virus (VZV). The other is a recombinant vaccine (RZV) based on the VZV glycoprotein E (gE) combined with AS01B, a multicomponent adjuvant system. RZV is superior to ZVL in efficacy, and differs from ZVL in that protection is not diminished by the age of the vaccinee and has not waned significantly during 4 years of follow-up. Immunologic studies demonstrated higher peak memory and persistence of T cell responses in RZV compared with ZVL recipients. RZV recipients also showed development and persistence of polyfunctional T cell responses. Taken together, we conclude that the immunologic data parallel and support the higher efficacy over time of RZV compared with ZVL.

Herpes Zoster DNA Vaccines with IL-7 and IL-33 Molecular Adjuvants Elicit Protective T Cell Immunity

Herpes zoster (HZ), or shingles, is caused by the reactivation of latent varicella-zoster virus (VZV) from the sensory ganglia when VZV-specific T-cell immunity is decreased because of aging or immunosuppression. In the present study, we developed HZ DNA vaccine candidates encoding VZV proteins and cytokine adjuvants, such as IL-7 and IL-33. We immunized C57BL/6 mice with DNA plasmids encoding VZV glycoprotein E (gE), immediate early (IE) 63, or IE62 proteins and found that robust VZV protein-specific T-cell responses were elicited by HZ DNA vaccination. Co-administration of DNA plasmids encoding IL-7 or IL-33 in HZ DNA vaccination significantly enhanced the magnitude of VZV protein-specific T-cell responses. Protective immunity elicited by HZ DNA vaccination was proven by challenge experiments with a surrogate virus, vaccinia virus expressing gE (VV-gE). A single dose of HZ DNA vaccine strongly boosted gE-specific T-cell responses in mice with a history of previous infection by VV-gE. Thus, HZ DNA vaccines with IL-7 and IL-33 adjuvants strongly elicit protective immunity.

Emerging Topics in Vaccine Therapeutics for Adolescents and Adults: An Update for Immunizing Pharmacists

Vaccine therapeutics and the practice of immunization provision are ever-changing. As pharmacy-based immunization services continue to flourish in the United States, more and more patients are requesting both routine and travel vaccines in community pharmacies. However, vaccine recommendations from the Centers for Disease Control and Prevention/Advisory Committee on Immunization Practices (CDC/ACIP) can sometimes differ from product-specific US Food and Drug Administration (FDA)-indicated uses. In addition, changes in vaccine schedules, product availability, and disease outbreaks can present immunizing pharmacists with scenarios requiring a high level of clinical judgment. Thus, it is of paramount importance that all immunizing pharmacists maintain competency in the most recent evidence in vaccine therapeutics, as well as practice standards for vaccine provision and administration. This review provides an update of the most recent literature surrounding emerging topics in adolescent and adult immunizations—highlighting influential studies and recent developments in the prevention of herpes zoster, human papillomavirus (HPV), measles, mumps, rubella (MMR), meningococcal disease, tetanus, diphtheria, and pertussis. Key concepts discussed include the emergence of the new recombinant zoster vaccine (RZV), meningococcal vaccine product selection, MMR revaccination during disease outbreaks, tetanus vaccine product selection, and duration of pertussis immunity with vaccination.

Recombinant Zoster Vaccine (Shingrix) to Prevent Herpes Zoster

Women ages 50 years and older are at risk for herpes zoster, a reactivated virus from varicella zoster virus (chickenpox) that causes a painful vesicular rash and can result in postherpetic neuralgia. It is estimated that one in three adults will be affected by herpes zoster in their lifetime. Research evidence points to the need to prevent herpes zoster through vaccination. Since 2006, clinicians have been vaccinating adults with zoster vaccine live (brand name Zostavax), but the efficacy of this vaccine wanes with time and advanced age. In October 2017, the U.S. Food and Drug Administration approved recombinant zoster vaccine under the brand name Shingrix to prevent herpes zoster. Studies have shown significantly better efficacy of Shingrix versus Zostavax. This article summarizes new guidance regarding vaccination with Shingrix and discusses implications for women's health.