Cellular and Humoral Responses to a Second Dose of Herpes Zoster Vaccine Administered 10 Years After the First Dose Among Older Adults

Exploring the Link between Varicella-Zoster Virus, Autoimmune Diseases, and the Role of Recombinant Zoster Vaccine

The varicella-zoster virus (VZV) is a human neurotropic herpes virus responsible for varicella and herpes zoster (HZ). Following primary infection in childhood, VZV manifests as varicella (chickenpox) and enters a period of latency within the dorsal root ganglion. A compromised cellular immune response due to aging or immunosuppression triggers viral reactivation and the development of HZ (shingles). Patients with autoimmune diseases have a higher risk of developing HZ owing to the immunodeficiency associated with the disease itself and/or the use of immunosuppressive agents. The introduction of new immunosuppressive agents with unique mechanisms has expanded the treatment options for autoimmune diseases but has also increased the risk of HZ. Specifically, Janus kinase (JAK) inhibitors and anifrolumab have raised concerns regarding HZ. Despite treatment advances, a substantial number of patients suffer from complications such as postherpetic neuralgia for prolonged periods. The adjuvanted recombinant zoster vaccine (RZV) is considered safe and effective even in immunocompromised patients. The widespread adoption of RZV may reduce the health and socioeconomic burdens of HZ patients. This review covers the link between VZV and autoimmune diseases, assesses the risk of HZ associated with immunosuppressant use, and discusses the benefits and risks of using RZV in patients with autoimmune diseases.

Vaccines for the Elderly and Vaccination Programs in Europe and the United States

The share of the elderly population is growing worldwide as life expectancy increases. Immunosenescence and comorbidities increase infectious diseases' morbidity and mortality in older adults. Here, we aimed to summarize the latest findings on vaccines for the elderly against herpes zoster, influenza, respiratory syncytial virus (RSV), COVID-19, and pneumococcal disease and to examine vaccine recommendation differences for this age group in Europe and the United States. PubMed was searched using the keywords "elders" and "vaccine" alongside the disease/pathogen in question and paraphrased or synonymous terms. Vaccine recommendations were also sought in the European and US Centers for Disease Control and Prevention databases. Improved vaccines, tailored for the elderly, mainly by using novel adjuvants or by increasing antigen concentration, are now available. Significant differences exist between immunization policies, especially between European countries, in terms of the recipient's age, number of doses, vaccination schedule, and implementation (mandatory or recommended). Understanding the factors that influence the immune response to vaccination in the elderly may help to design vaccines that offer long-term protection for this vulnerable age group. A consensus-based strategy in Europe could help to fill the gaps in immunization policy in the elderly, particularly regarding vaccination against RSV and pneumococcus.

Knowledge About the Herpes Zoster (HZ) Vaccine and Its Acceptance Among the Population in Al-Ahsa City in the Kingdom of Saudi Arabia

Introduction Herpes zoster (HZ), caused by the varicella-zoster virus (VZV), poses a public health concern in Saudi Arabia, with an increasing number of cases reported in recent years. This study aimed to assess the knowledge and acceptance of the herpes zoster vaccine among Saudi Arabian citizens in Al-Ahsa. Methodology A descriptive cross-sectional study was conducted using online surveys administered via social media platforms. The study was conducted in Al-Ahsa, a city located in the Eastern Province of Saudi Arabia. Al-Ahsa serves as a representative urban area within Saudi Arabia. Result The study found a high level of awareness and knowledge about the vaccine, with 78.2% of the participants having heard of herpes zoster. The majority considered the vaccine effective (89%) and believed it was available in Saudi Arabia (87%). However, the vaccination rate was only 8%. The study revealed varied opinions on the target population for vaccination, with 39.7% favoring immunocompromised patients and 38.1% choosing individuals above 50 years. The reasons for not being vaccinated included a lack of information (38.3%) and the belief of being in good health (37.3%). Conclusion The findings suggest a need for targeted educational campaigns to address misconceptions and promote vaccination, particularly among healthcare providers and the recommended target populations. Future research should explore barriers to vaccination to inform tailored interventions.

Predictors of 5-Year Persistence of Antibody Responses to Zoster Vaccines

BACKGROUND

Protection against herpes zoster is primarily conferred by cell-mediated immunity. However, anti-varicella-zoster virus (VZV) glycoprotein (anti-gp) antibody responses to zoster vaccine live (ZVL) are correlated with protection, suggesting a potential protective role for antibody. Detailed studies of antibody responses to the recombinant zoster vaccine (RZV) are provided.

METHODS

We compared enzyme-linked immunosorbent assay-measured anti-VZV glycoproteins (anti-gp) and glycoprotein E (anti-gE) antibody levels and avidity in 159 participants randomized to RZV (n = 80) or ZVL (n = 79) recipients over 5 years after vaccination and identified predictors of antibody persistence.

RESULTS

The comparison between vaccine groups showed higher anti-gE and anti-gp antibody levels after RZV than after ZVL over the 5-year study duration. RZV recipients also had higher anti-gE avidity for 5 years and higher anti-gp avidity in the first year after vaccination. Compared with prevaccination levels, RZV recipients maintained higher levels of anti-gE antibodies and avidity for 5 years, whereas ZVL recipients only maintained higher anti-gE avidity. Anti-gp antibody levels and avidity decreased to prevaccination levels or below beyond 1 year after vaccination in both groups. Independent predictors of persistence of antibody levels and avidity included vaccine type, prevaccination and peak antibody levels and avidity, prevaccination and peak cell-mediated immunity, and age. Sex or prior ZVL administration did not affect persistence.

CONCLUSIONS

Antibody responses and avidity were higher and more persistent in RZV than in ZVL recipients. The effect of age on antibody persistence in RZV recipients is novel.

Longitudinal changes in cell-mediated immunity after varicella-zoster virus skin test in the general population; Shozu Herpes Zoster Study: SHEZ study

Varicella-zoster virus-specific cell-mediated immunity has been associated with the onset and severity of herpes zoster (HZ), and the administration of the HZ vaccine enhanced the immunity. However, limited data is available on the duration of cell-mediated immunity enhancement by soluble antigen of varicella-zoster virus (VZV) skin test. A prospective, community-based cohort study was conducted in Shozu County, Kagawa Prefecture, Japan. Repeated VZV skin tests containing inactivated VZV antigen and blood tests were performed on 365 subjects aged 60 years and older at baseline, 1, 2, and 3 years later. The differential immunity indices of VZV over time for cell-mediated and humoral immunity were evaluated. VZV skin test reaction and ELISpot counts increased significantly at 1, 2, and 3 years later compared to the baseline. However, humoral immunity indices did not change materially over time. Soluble antigen by VZV skin test enhanced VZV-specific cell-mediated immunity, and it persisted for at least 1 year. In addition, the inoculation with inactivated antigens every year by VZV skin test continued to enhance VZV-specific cell-mediated immunity after 2 and 3 years.

Cost-Effectiveness Analysis of Herpes Zoster Vaccination in 50- to 85-Year-Old Immunocompetent Belgian Cohorts: A Comparison between No Vaccination, the Adjuvanted Subunit Vaccine, and Live-Attenuated Vaccine

BACKGROUND

A new adjuvanted subunit vaccine (HZ/su), with higher vaccine efficacy than live-attenuated vaccine (ZVL), has been licensed in Europe since March 2018. Therefore, Belgian decision-makers might need to re-assess their recommendations for vaccination against herpes zoster (HZ).

METHODS

We conducted a cost-effectiveness analysis, using a Markov decision tree, of vaccinating 50- to 85-year-old immunocompetent Belgian cohorts with no vaccination, HZ/su, ZVL, and ZVL with booster after 10 years. Due to the uncertainty in vaccine waning of HZ/su vaccine beyond 4 years, we used a logarithmic and 1-minus-exponential function to model respectively a long and short duration of protection. We used a lifetime time horizon and implemented the health care payer perspective throughout the analysis.

RESULTS

HZ/su had the greatest impact in avoiding health and economic burden. However, it would never become cost-effective at a willingness-to-pay threshold of €40,000 per quality-adjusted life year (QALY) gained at its market price set by the manufacturer in the USA. Depending on the waning function assumed for HZ/su, the price per dose needs to drop 60% or 83% such that vaccination with HZ/su, assuming respectively a long or short duration of protection, would become cost-effective in 50- and 80-year-old individuals. At €40,000 per QALY gained, ZVL or ZVL with booster was never found cost-effective compared with HZ/su, even if only administration cost was considered.

CONCLUSION

HZ/su is cost-effective in the 50-year-old age cohort at the unofficial Belgian threshold of €40,000 per QALY gained, if its price drops to €55.40 per dose. This result is, however, very sensitive to the assumed duration of protection of the vaccine, and the assumed severity and QALY loss associated with HZ and post-herpetic neuralgia (PHN).

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).

The Adjuvanted Recombinant Zoster Vaccine in Adults Aged ≥65 Years Previously Vaccinated With a Live-Attenuated Herpes Zoster Vaccine

BACKGROUND

Efficacy of the live-attenuated herpes zoster (HZ) vaccine (ZVL) wanes substantially over time. We evaluated immunogenicity and safety of the adjuvanted recombinant zoster vaccine (RZV) in previous ZVL recipients.

METHODS

Adults aged ≥65 years who were previously vaccinated with ZVL ≥5 years earlier (n = 215) were group-matched with ZVL-naive individuals (n = 215) and vaccinated with RZV. Glycoprotein E (gE)-specific humoral and cell-mediated immune responses and the correlation between them, polyfunctional gE-specific CD4 T-cell responses, safety, and confirmed HZ cases were assessed.

RESULTS

Through 12 months after dose 2, anti-gE antibody concentrations, gE-specific CD4 T-cell frequencies, and activation marker profiles were similar between groups. Safety outcomes were also similar. No HZ episodes were confirmed.

CONCLUSIONS

RZV induced strong humoral and polyfunctional cell-mediated immune responses that persisted above prevaccination levels through 1 year after dose 2 in adults aged ≥65 years irrespective of previous ZVL vaccination. The RZV safety profile was not affected.

CLINICAL TRIALS REGISTRATION

NCT02581410.

Oral Polio Vaccine to Protect Against COVID-19: Out of the Box Strategies?

The global coronavirus disease 2019 pandemic has raised significant concerns of developing rapid, broad strategies to protect the vulnerable population and prevent morbidity and mortality. However, even with an aggressive approach, controlling the pandemic has been challenging, with concerns of emerging variants that likely escape vaccines, nonadherence of social distancing/preventive measures by the public, and challenges in rapid implementation of a global vaccination program that involves mass production, distribution, and execution. In this review, we revisit the utilization of attenuated vaccinations, such as the oral polio vaccine, which are safe, easy to administer, and likely provide cross-protection against respiratory pathogens. We discuss the rationale and data supporting its use and detail description of available vaccines that could be repurposed for curtailing the pandemic.

Tapping the immunological imprints to design chimeric SARS-CoV-2 vaccine for elderly population

The impact of SARS-CoV-2 and COVID-19 disease susceptibility varies depending on the age and health status of an individual. Currently, there are more than 140 COVID-19 vaccines under development. However, the challenge will be to induce an effective immune response in the elderly population. Analysis of B cell epitopes indicates the minor role of the stalk domain of spike protein in viral neutralization due to low surface accessibility. Nevertheless, the accumulation of mutations in the receptor-binding domain (RBD) might reduce the vaccine efficacy in all age groups. We also propose the concept of chimeric vaccines based on the co-expression of SARS-CoV-2 spike and influenza hemagglutinin (HA) and matrix protein 1 (M1) proteins to generate chimeric virus-like particles (VLP). This review discusses the possible approaches by which influenza-specific memory repertoire developed during the lifetime of the elderly populations can converge to mount an effective immune response against the SARS-CoV-2 spike protein with the possibilities of designing single vaccines for COVID-19 and influenza. HighlightsImmunosenescence aggravates COVID-19 symptoms in elderly individuals.Low immunogenicity of SARS-CoV-2 vaccines in elderly population.Tapping the memory T and B cell repertoire in elderly can enhance vaccine efficiency.Chimeric vaccines can mount effective immune response against COVID-19 in elderly.Chimeric vaccines co-express SARS-CoV-2 spike and influenza HA and M1 proteins.

Ageing of Immune System and Response to a Live-Attenuated Herpes Zoster Vaccine in Lung Transplant Candidates

The mean age of lung transplant recipients has significantly increased in recent decades. Elderly recipients have a higher risk of developing herpes zoster (HZ), and they have in general a worse response to vaccination than younger persons do. We investigated the relationship between the humoral and cellular immune response to a live-attenuated HZ vaccine (Zostavax^®, Merck Sharp and Dohme) and the frequencies of T and B cell subsets, especially aged cell subsets (CD28−T cells and age associated B cells, ABCs). In total, 37 patients awaiting lung transplantation received one dose of Zostavax^®, and peripheral blood was collected before and within 6 months after vaccination. We observed a robust immune response after vaccination. The frequencies of CD28−T cells before vaccination had no impact on the subsequent immune response to HZ vaccination. However, a higher frequency of ABCs before vaccination correlated with a lower immune response especially regarding the cellular immune response. Cytomegalovirus seropositivity was associated with increased frequencies of CD28−T cells but not with frequencies of ABCs in the patients. In conclusion, increased levels of ABCs might disturb the cellular immune response to HZ vaccination, which could lower the efficacy of such vaccination in elderly transplant recipients.

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.

Understanding immunosenescence and its impact on vaccination of older adults

Older adults are more susceptible to viral and bacterial infection, and experience higher incidence and severity of infectious diseases. Although vaccination is the most logical solution in preventing infectious diseases, primary vaccine responses in individuals aged ≥65 years-old fail to generate complete protection. This is presumably attributed to immunosenescence, a term that describes functional differences associated with the immune system and natural age advancement. Both the innate and adaptive immune systems experience age-related impairments that contribute to insufficient protection following vaccination. This review addresses current knowledge of age-related changes that affect vaccine responsiveness; including the deficits in innate cell functions, dampened humoral and cell-mediated immune responses, current vaccination schedules for older adults, and concludes with potential strategies for improving vaccine efficacy specifically for this age group. Due to an age-related decline in immunity and poor vaccine responses, infectious diseases remain a burden among the aged population.

Prophylactic vaccination with a live-attenuated herpes zoster vaccine in lung transplant candidates

BACKGROUND

Herpes zoster (HZ) is caused by the reactivation of varicella-zoster virus (VZV). Patients with lung transplants are at high risk for HZ owing to their immunocompromised status and the need for lifelong immunosuppression. In this study, patients on the waiting list for lung transplantation were vaccinated by a live-attenuated HZ vaccine (Zostavax, Merck Sharp & Dohme), and the safety and immunogenicity of this vaccine were studied.

METHODS

In total, 105 patients with end-stage pulmonary disease (ESPD) were enrolled (68 participants received 1 dose of Zostavax and 37 participants were enrolled as unvaccinated controls). Among them, 43 patients underwent lung transplantation and were followed up for further analysis. VZV immunoglobulin G antibody titers and VZV-specific cell-mediated immunity (CMI) on multiple time points before and after vaccination and before and after transplantation were measured.

RESULTS

Immune response to Zostavax was higher in younger patients, highest within 3 months after vaccination, and not influenced by gender or type of ESPD. Age, cytomegalovirus serostatus, and immunity to VZV at baseline impacted the subsequent immune response to the vaccine. Short-term immunosuppressant treatment had strong effects on VZV CMI levels, which returned to a high level at 6 months after transplantation in vaccinated patients. Zostavax did not impact infection or rejection rate after transplantation.

CONCLUSIONS

Zostavax was safe and induced a robust humoral and cellular response for patients awaiting lung transplantation regardless of the type of ESPD. Patients younger than the recommended vaccination age of over 50 years showed a strong response and could also benefit from pre-transplant immunization.

Herpes zoster vaccination in Australia: what's available and who benefits?

Acute herpes zoster and associated postherpetic neuralgia is caused by reactivation of latent varicella zoster virus. It can be debilitating for older adults and interfere with activities of daily living

A live, attenuated single-dose vaccine, that protects against both acute herpes zoster and postherpetic neuralgia, is available for free to all Australians aged 70 years, and in a catch-up program for those aged 71–79 years

The vaccine is contraindicated in people who are immunocompromised, but can be considered in those who are receiving low doses of selected disease-modifying antirheumatic drugs

Records of the Australian Immunisation Register suggest that only a third of 70 year olds received the vaccine in the first year-and-a-half of the program. This is likely an underestimation, but emphasises the importance of ensuring the vaccine is offered to all eligible patients and that vaccination is recorded on the Register

A non-live recombinant herpes zoster vaccine has recently been developed which is more efficacious than the live vaccine in clinical trials. It is registered in Australia but not currently available

[Alterations in responses to vaccines in older people]

The aging population raises a number of public health issues including a need to address the severity and frequency of infections observed in older people. Vaccines play an important role in prevention. However, immunosenescence alters the intensity and quality of vaccine responses, thus limiting the impact of recommendations directed after 65 years for vaccination against flu, pneumococci, pertussis, tetanus and zoster. Immunosenescence, aggravated by co-morbidities, varies with age, becoming apparent after 60-65 years and more profound after 85 years. All stages of vaccine responses are affected by immunosenescence, from the innate immunity required to activate these responses to the induction of protective antibody responses and immune memory. Nevertheless, the capacity to develop new responses to primary vaccination is more affected than the ability to respond to recalls, although this is also impaired. Responses to vaccines are differentially altered depending on vaccine and age. Influenza vaccines are modestly immunogenic and several meta-analyses agree an estimate for efficacy of about 50% against virologically-proven flu and 40% against flu-related deaths. The anti-pneumococcal 23-valent non-conjugated vaccine does not induce memory while the 13-valent conjugated one does, but their efficacy are likely to be similar between 70 to 52% before 75 years. A sequential vaccination program with the 13-valent primo-vaccination followed by the 23-valent, recommended in immune-suppressed patients, is currently being studied in France. The waning of immunity to pertussis makes recalls necessary in the elderly who develop good antibody responses. Several research avenues are currently being pursued to try improve the degree of protection conferred by these vaccines in elderly.

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.

The Effect of Age on the Immunogenicity of the Live Attenuated Zoster Vaccine Is Predicted by Baseline Regulatory T Cells and Varicella-Zoster Virus-Specific T Cell Immunity

Older age is associated with increased infectious morbidity and decreased immune responses to vaccines, but the mechanisms that mediate this effect are incompletely understood. The efficacy and immunogenicity of the live attenuated zoster vaccine (ZVL) have a very-well-described negative association with the age of the vaccinee. In a study of 600 ZVL recipients 50 to >80 years of age, we investigated immunological factors that might explain the effect of age on the immunogenicity of ZVL. Using FluoroSpot assays and flow cytometry, we determined that varicella-zoster virus (VZV)-specific peak T helper 1 (VZV-Th1) responses to ZVL were independently predicted by prevaccination VZV-Th1 responses, regulatory T cells (Treg), and PD1-expressing immune checkpoint T cells (Tcheck) but not by the age of the vaccinee. Persistence of VZV-Th1 1 year after vaccination was independently predicted by the factors mentioned above, by peak VZV-Th1 responses to ZVL, and by the age of the vaccinee. We further demonstrated by ex vivo blocking experiments the mechanistic role of PD1 and CTLA4 as modulators of decreased VZV-Th1 responses in the study participants. VZV-specific cytotoxic T cell (VZV-CTL) and T follicular helper responses to ZVL did not correlate with age, but similar to other Th1 responses, VZV-CTL peak and baseline responses were independently correlated. These data expand our understanding of the factors affecting the magnitude and kinetics of T cell responses to ZVL in older adults and show the importance of prevaccination Treg and Tcheck in modulating the immunogenicity of ZVL. This presents new potential interventions to increase vaccine responses in older adults.IMPORTANCE Vaccination is the most effective method to protect older adults against viral infections. However, the immunogenicity of viral vaccines in older adults is notoriously poor. The live attenuated zoster vaccine (ZVL) provides the best example of a gradual decrease of vaccine immunogenicity with every 10-year age increase above 50 years. Here we show that the abundance of regulatory T cells before vaccine administration to older adults has a significant inhibitory effect on immune responses to ZVL and, together with baseline immunity to varicella-zoster virus, explains the effect of age on the immunogenicity of ZVL. Moreover, in vitro blockade of regulatory T cell mechanisms of action with biologic modulators restores immune responses to varicella-zoster virus in vaccinees. Collectively, these observations suggest that immune modulators that block regulatory T cell activity may increase responses to viral attenuated vaccines in older adults.

Antibody and B cell responses to an investigational adjuvanted RSV vaccine for older adults

Background: Infections with respiratory syncytial virus (RSV) cause significant morbidity and hospitalization in older adults. We studied the humoral, mucosal and B cell responses of an investigational adjuvanted RSV sF vaccine, MEDI7510, in older adults. Methods: In a substudy of a randomized (1:1), double-blind, placebo-controlled study of MEDI7510 in adults ≥60 years of age, we collected blood and nasal secretions at days 0, 8, 29, 91 and 180 post-vaccination to measure F-specific IgG and IgA antibodies by ELISA, and plasmablasts and memory B cells by IgA/IgG dual-color fluorospot. Results: The 27 vaccine- and 18 placebo-recipients had a mean age of 73 years and included 24 women. Among vaccinees, 93% had significant increases in F-specific plasma IgG 85% had increased plasma IgA; 74% had increased nasal IgG and 26% nasal IgA; 93% had IgG and 89% IgA plasmablasts on Day 8 post-immunization; and 82% had IgG and 7.4% IgA memory B cell responses to the vaccine. Vaccinees <70 years of age and women had the highest responses to the vaccine. Conclusions: This adjuvanted vaccine generated robust humoral immune responses in older adults, including RSV F-specific systemic and mucosal antibodies and memory B cells. Nevertheless, age ≥70 years was associated with decreased immunogenicity of the adjuvanted vaccine.

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.

Evaluation of Varicella-zoster virus-specific cell-mediated immunity by interferon-γ Enzyme-Linked Immunosorbent Assay in adults ≥50 years of age administered a herpes zoster vaccine

Varicella-zoster virus (VZV)-specific cell-mediated immunity (CMI) is critical for preventing and controlling the onset of herpes zoster (HZ). To assess VZV CMI, an interferon-γ (IFN-γ) enzyme-linked immunosorbent assay (ELISA) was validated by examining the influence of VZV-specific antigen content, incubation time, and interval from whole blood collection on the assay. In phase II clinical trial, VZV-specific CMI in adults ≥50 years of age administered an HZ vaccine were evaluated by IFN-γ ELISA, as determined by measuring IFN-γ production in the whole blood in response to stimulation with ultraviolet light-inactivated VZV. The VZV-specific IFN-γ levels varied among individuals from prevaccination (baseline) to 6 weeks postvaccination. In most subjects, VZV-specific CMI was increased at 6 weeks postvaccination. The HZ vaccine elicited a significant increase in the VZV-specific CMI response as measured by ELISA; the geometric mean fold-rises from baseline to 6 weeks postvaccination were 3.50, 4.22, and 5.24 in the 4.3, 4.7, and 4.9 log plaque-forming unit vaccine groups, respectively, which was significantly higher than in the placebo group (P < 0.05). These results indicate that vaccination enhances the VZV-specific CMI responses in subjects; IFN-γ ELISA is an effective method for evaluating the CMI response and may be useful for identifying individuals at a high risk of HZ infection.

Optimal Timing of Zoster Vaccination After Shingles: A Prospective Study of the Immunogenicity and Safety of Live Zoster Vaccine

Background

Zoster vaccination is recommended for people with a history of herpes zoster (HZ), but the most effective timing of vaccine administration after zoster illness is unresolved. This prospective observational study compared the immunogenicity and safety of administering HZ vaccine at 6-12 months and 1-5 years after zoster illness.

Materials and Methods

Blood samples were collected before the administration of live zoster vaccine and 6 weeks after vaccination. Varicella-zoster virus (VZV) IgG concentrations and T-cell responses were assessed by glycoprotein enzyme-linked immunosorbent assay and interferon-γ enzyme-linked immunospot assay (ELISPOT), respectively.

Results

The baseline geometric mean value (GMV) of VZV IgG was higher in the 6-12 months group than in the 1-5 years group (245.5 IU/mL vs. 125.9 IU/mL; P = 0.021). However, the GMV increased significantly in both groups (P = 0.002 in the 6-12 months group; P <0.001 in the 1-5 years group). The results of the ELISPOT assay were not significant for differences of the GMV between baseline and 6-week post-vaccination groups, while the GMV increased significantly in both groups (P = 0.001 in the 6-12 months group; P <0.001 in the 1-5 years group).

Conclusion

The immunogenicity of zoster vaccine may be similar whether administered 6-12 months, or >1 year after zoster illness.

Trial Registration

ClinicalTrials.gov Identifier: NCT02704572

Association between quantitative varicella-zoster virus antibody levels and zoster reactivation in HIV-infected persons

Background

Varicella-zoster virus (VZV) reactivation is common but difficult to predict in HIV-infected persons.

Objective

Since qualitative VZV antibodies can determine past VZV disease or vaccination, we evaluated whether quantitative VZV antibody levels over time can predict future zoster.

Study design

US Military HIV Natural History (NHS) participants with a zoster diagnosis at least 5 years after HIV diagnosis (n = 100) were included. Zoster-negative controls (n = 200) were matched by age, race, gender, and CD4 count at HIV diagnosis. Repository plasma specimens collected at baseline and prior to zoster diagnosis were evaluated using a quantitative anti-VZV ELISA assay. Differences in quantitative VZV levels were analyzed by Wilcoxon Mann–Whitney and Fisher’s exact tests.

Results

Median CD4 count at HIV diagnosis was similar for cases and controls (535 [IQR 384–666] vs. 523 [IQR 377–690] cells/μL; p = 0.940), but lower for cases at zoster diagnosis (436 [IQR 277–631] vs. 527 [IQR 367–744] cells/μL; p = 0.007). Antiretroviral therapy (ART) use prior to zoster diagnosis was lower for cases (52.0%) compared to controls (64.5%; p = 0.025). Cases had similar mean VZV antibody levels prior to zoster diagnosis compared to controls [2.25 ± 0.85 vs. 2.44 ± 0.96 index value/optical density (OD) ratio; p = 0.151] with no difference in the change in antibody levels over time (0.08 ± 0.71 vs. 0.01 ± 0.94 index value/OD per year; p = 0.276).

Conclusion

Quantitative VZV antibody levels are stable in HIV-infected persons and do not predict zoster reactivation. Low CD4 count and lack of ART use appear to be better predictors of future zoster diagnosis.

Cost-effectiveness of vaccination of immunocompetent older adults against herpes zoster in the Netherlands: a comparison between the adjuvanted subunit and live-attenuated vaccines

BACKGROUND

The newly registered adjuvanted herpes zoster subunit vaccine (HZ/su) has a higher efficacy than the available live-attenuated vaccine (ZVL). National decision-makers soon need to decide whether to introduce HZ/su or to prefer HZ/su above ZVL.

METHODS

Using a Markov model with a decision tree, we conducted a cost-effectiveness analysis of vaccination with HZ/su (two doses within 2 months) or zoster vaccine live (ZVL) (single dose, or single dose with a booster after 10 years) for cohorts of 50-, 60-, 70- or 80-year-olds in the Netherlands. The model was parameterized using vaccine efficacy data from randomized clinical trials and up-to-date incidence, costs and health-related quality of life data from national datasets. We used a time horizon of 15 years, and the analysis was conducted from the societal perspective.

RESULTS

At a coverage of 50%, vaccination with two doses of HZ/su was estimated to prevent 4335 to 10,896 HZ cases, depending on the cohort age. In comparison, this reduction was estimated at 400-4877 for ZVL and 427-6466 for ZVL with a booster. The maximum vaccine cost per series of HZ/su to remain cost-effective to a willingness-to-pay threshold of €20,000 per quality-adjusted life year (QALY) gained ranged from €109.09 for 70-year-olds to €63.68 for 50-year-olds. The cost-effectiveness of ZVL changed considerably by age, with corresponding maximum vaccine cost per dose ranging from €51.37 for 60-year-olds to €0.73 for 80-year-olds. Adding a ZVL booster after 10 years would require a substantial reduction of the maximum cost per dose to remain cost-effective as compared to ZVL single dose. Sensitivity analyses on the vaccine cost demonstrated that there were scenarios in which vaccination with either HZ/su (two doses), ZVL single dose or ZVL + booster could be the most cost-effective strategy.

CONCLUSIONS

A strategy with two doses of HZ/su was superior in reducing the burden of HZ as compared to a single dose or single dose + booster of ZVL. Both vaccines could potentially be cost-effective to a conventional Dutch willingness-to-pay threshold for preventive interventions. However, whether HZ/su or ZVL would be the most cost-effective alternative depends largely on the vaccine cost.

Efficacy, effectiveness, and safety of herpes zoster vaccines in adults aged 50 and older: systematic review and network meta-analysis

OBJECTIVE

To compare the efficacy, effectiveness, and safety of the herpes zoster live attenuated vaccine with the herpes zoster adjuvant recombinant subunit vaccine or placebo for adults aged 50 and older.

DESIGN

Systematic review with bayesian meta-analysis and network meta-analysis.

DATA SOURCES

Medline, Embase, and Cochrane Library (inception to January 2017), grey literature, and reference lists of included studies.

ELIGIBILITY CRITERIA FOR STUDY SELECTION

Experimental, quasi-experimental, and observational studies that compared the live attenuated vaccine with the adjuvant recombinant subunit vaccine, placebo, or no vaccine in adults aged 50 and older. Relevant outcomes were incidence of herpes zoster (primary outcome), herpes zoster ophthalmicus, post-herpetic neuralgia, quality of life, adverse events, and death.

RESULTS

27 studies (22 randomised controlled trials) including 2 044 504 patients, along with 18 companion reports, were included after screening 2037 titles and abstracts, followed by 175 full text articles. Network meta-analysis of five randomised controlled trials found no statistically significant differences between the live attenuated vaccine and placebo for incidence of laboratory confirmed herpes zoster. The adjuvant recombinant subunit vaccine, however, was statistically superior to both the live attenuated vaccine (vaccine efficacy 85%, 95% credible interval 31% to 98%) and placebo (94%, 79% to 98%). Network meta-analysis of 11 randomised controlled trials showed the adjuvant recombinant subunit vaccine to be associated with statistically more adverse events at injection sites than the live attenuated vaccine (relative risk 1.79, 95% credible interval 1.05 to 2.34; risk difference 30%, 95% credible interval 2% to 51%) and placebo (5.63, 3.57 to 7.29 and 53%, 30% to 73%, respectively). Network meta-analysis of nine randomised controlled trials showed the adjuvant recombinant subunit vaccine to be associated with statistically more systemic adverse events than placebo (2.28, 1.45 to 3.65 and 20%, 6% to 40%, respectively).

CONCLUSIONS

Using the adjuvant recombinant subunit vaccine might prevent more cases of herpes zoster than using the live attenuated vaccine, but the adjuvant recombinant subunit vaccine also carries a greater risk of adverse events at injection sites.

PROTOCOL REGISTRATION

Prospero CRD42017056389.

A novel nonlive, adjuvanted herpes zoster subunit vaccine: a report on the emerging clinical data and safety profile

Herpes zoster (HZ) is an acute vesicular dermatitis with a typical dermatomal distribution, caused by the varicella zoster virus (VZV), often preceded and accompanied by prodromal pain or pruritus. HZ may be related to several complications such as postherpetic neuralgia (PHN). The incidence and severity of the disease increase with aging, due to immunosenescence and in particular to the decline of the specific cell-mediated immunity (CMI). The impact of HZ in terms of morbidity and short- and long-term complications, the availability of suboptimal treatment options to date, and the high costs for the diagnostic and clinical-therapeutic management of patients have motivated the search for a new preventive approach through the development of a vaccine. The vaccine currently in use with live-attenuated virus (ZVL) has been shown to be effective in reducing the incidence of HZ, its impact, and the onset of PHN, although the efficacy is lower in older subjects and tends to decrease some years after immunization. A new adjuvanted recombinant subunit vaccine (HZ/su), containing the VZV glycoprotein E (gE) and the AS01B adjuvant system, is now a very promising alternative to ZVL; in several clinical studies, it showed a good safety profile and was able to elicit high immune humoral and cell-mediated responses, both maintained up to 9 years. Furthermore, HZ/su vaccine was effective both in preventing HZ and in reducing the onset of PHN and other complications. HZ/su has been recommended and preferred over ZVL by the Advisory Committee on Immunization Practices (ACIP) for the prevention of HZ and its complications in immunocompetent adults aged ≥50 years, even if already vaccinated with ZVL, through a two-dose schedule. HZ/su has been approved in Canada, USA, Europe, and Japan and is currently being approved in Australia. The aim of this review was to describe the epidemiological data, HZ and PHN risks and their impact on the social life and common life of infected people, and ZVL and HZ/su vaccine development including various clinical trials and efficacy, safety, and tolerability profiles.

Tale of two vaccines: differences in response to herpes zoster vaccines

About one-third of the US population will develop herpes zoster (HZ, commonly known as shingles) over a lifetime, while two-thirds will not. It is not clear exactly why certain people are susceptible to HZ; however, we may be coming closer to an answer. In this issue of the JCI, a study by Levin et al. provides important details concerning pathogenesis of and protection from HZ. The authors characterized differences in the immunologic responses induced by two HZ vaccines, the live attenuated zoster vaccine (ZV) and the more recently developed adjuvanted varicella-zoster virus (VZV) glycoprotein E (gE) subunit herpes zoster vaccine (HZ/su), in vaccine-naive subjects and those previously vaccinated with HZ. The observed differences in responses paralleled the observed clinical protection of the two zoster vaccines, with HZ/su being superior to HZ. Together, these results seem to explain immunologically why the new subunit vaccine outperforms the live vaccine. These differences may also provide clues as to why HZ develops in the first place.

Th1 memory differentiates recombinant from live herpes zoster vaccines

The adjuvanted varicella-zoster virus (VZV) glycoprotein E (gE) subunit herpes zoster vaccine (HZ/su) confers higher protection against HZ than the live attenuated zoster vaccine (ZV). To understand the immunologic basis for the different efficacies of the vaccines, we compared immune responses to the vaccines in adults 50 to 85 years old. gE-specific T cells were very low/undetectable before vaccination when analyzed by FluoroSpot and flow cytometry. Both ZV and HZ/su increased gE-specific responses, but at peak memory response (PMR) after vaccination (30 days after ZV or after the second dose of HZ/su), gE-specific CD4+ and CD8+ T cell responses were 10-fold or more higher in HZ/su compared with ZV recipients. Comparing the vaccines, T cell memory responses, including gE-IL-2+ and VZV-IL-2+ spot-forming cells (SFCs), were higher in HZ/su recipients and cytotoxic and effector responses were lower. At 1 year after vaccination, all gE-Th1 and VZV-IL-2+ SFCs remained higher in HZ/su compared with ZV recipients. Mediation analyses showed that IL-2+ PMR were necessary for the persistence of Th1 responses to either vaccine and VZV-IL-2+ PMR explained 73% of the total effect of HZ/su on persistence. This emphasizes the biological importance of the memory responses, which were clearly superior in HZ/su compared with ZV participants.

Determining the optimal strategy for the live-attenuated herpes zoster vaccine in adults

The optimal strategy for the vaccinating against herpes zoster (HZ) vaccine remains unknown. Cost-effectiveness analyses provide insight to the most cost-effective age groups but results vary across studies. The optimal strategy is important given that vaccine efficacy and duration vary depending on vaccination age. Therefore, small changes from the optimal age can affect long-term outcomes and produce sub-optimal results. The objective of this research was to determine the optimal timing policy for HZ vaccination. We simulated cohorts of men and women and use stochastic dynamic programming to evaluate the decision to vaccinate or defer each year from age 50 to 100. If the decision was to defer, the cohort risked developing HZ. If HZ occurred, the cohort was subjected to cost and quality-adjusted life year (QALY) loss for a typical HZ infection (including complications) at that age. If HZ did not occur, the decision was evaluated at the next age. Then, we extend the model to consider the case in which a booster vaccine is available. A set of probabilistic sensitivity analyses were conducted to check model robustness. Results show the optimal policy for women is to vaccinate between ages 66 and 77, and for men between ages 66 and 74, assuming a willingness to pay (WTP) of $100,000 per QALY. It becomes optimal to vaccinate earlier if a booster vaccine is available, and women have a wider range of ages than men. This research is the first to examine exactly when the HZ vaccine should be administered. It is also the first study, to our knowledge, that used stochastic dynamic programming to examine the question of a second dose for any vaccine. This research provides the first simple policy on when to vaccinate and re-vaccinate against HZ.

Herpes Zoster and Immunogenicity and Safety of Zoster Vaccines in Transplant Patients: A Narrative Review of the Literature

This narrative review focuses on the herpes zoster (HZ) and its prevention in transplant patients. Varicella zoster virus (VZV) is highly contagious and distributed worldwide in humans. Primary VZV infection usually causes varicella and then establishes a lifelong latency in dorsal root ganglia. Reactivation of VZV leads to HZ and related complications such as postherpetic neuralgia. Age and decreased immunity against VZV are important risk factors for developing HZ. Transplant patients are at increased risk for developing HZ and related complications due to their immunocompromised status and the need for lifetime immunosuppression. Diagnosis of HZ in transplant patients is often clinically difficult, and VZV-specific antibodies should be determined by serologic testing to document prior exposure to VZV during their pre-transplant evaluation process. Although antiviral agents are available, vaccination should be recommended for preventing HZ in transplant patients considering their complicated condition and weak organ function. Currently, there are two licensed HZ vaccines, of which one is a live-attenuated vaccine and the other is a HZ subunit vaccine. Both vaccines have shown promising safety and efficacy in transplants patients and especially the subunit vaccine could be administered post-transplant since this vaccine does not contain any live virus. Larger studies are needed about safety and immunogenicity of HZ vaccines in transplant populations, and extra efforts are needed to increase vaccine usage according to guidelines.

Breadth and Functionality of Varicella-Zoster Virus Glycoprotein-Specific Antibodies Identified after Zostavax Vaccination in Humans

Herpes zoster (HZ) (shingles) is the clinical manifestation of varicella-zoster virus (VZV) reactivation. HZ typically develops as people age, due to decreased cell-mediated immunity. However, the importance of antibodies for immunity against HZ prevention remains to be understood. The goal of this study was to examine the breadth and functionality of VZV-specific antibodies after vaccination with a live attenuated HZ vaccine (Zostavax). Direct enumeration of VZV-specific antibody-secreting cells (ASCs) via enzyme-linked immunosorbent spot assay (ELISPOT assay) showed that Zostavax can induce both IgG and IgA ASCs 7 days after vaccination but not IgM ASCs. The VZV-specific ASCs range from 33 to 55% of the total IgG ASCs. Twenty-five human VZV-specific monoclonal antibodies (MAbs) were cloned and characterized from single-cell-sorted ASCs of five subjects (>60 years old) who received Zostavax. These MAbs had an average of ∼20 somatic hypermutations per VH gene, similar to those seen after seasonal influenza vaccination. Fifteen of the 25 MAbs were gE specific, whereas the remaining MAbs were gB, gH, or gI specific. The most potent neutralizing antibodies were gH specific and were also able to inhibit cell-to-cell spread of the virus in vitro Most gE-specific MAbs were able to neutralize VZV, but they required the presence of complement and were unable to block cell-to-cell spread. These data indicate that Zostavax induces a memory B cell recall response characterized by anti-gE > anti-gI > anti-gB > anti-gH antibodies. While antibodies to gH could be involved in limiting the spread of VZV upon reactivation, the contribution of anti-gE antibodies toward protective immunity after Zostavax needs further evaluation.IMPORTANCE Varicella-zoster virus (VZV) is the causative agent of chickenpox and shingles. Following infection with VZV, the virus becomes latent and resides in nerve cells. Age-related declines in immunity/immunosuppression can result in reactivation of this latent virus, causing shingles. It has been shown that waning T cell immunity correlates with an increased incidence of VZV reactivation. Interestingly, serum with high levels of VZV-specific antibodies (VariZIG; IV immunoglobulin) has been administered to high-risk populations, e.g., immunocompromised children, newborns, and pregnant women, after exposure to VZV and has shown some protection against chickenpox. However, the relative contribution of antibodies against individual surface glycoproteins toward protection from shingles in elderly/immunocompromised individuals has not been established. Here, we examined the breadth and functionality of VZV-specific antibodies after vaccination with the live attenuated VZV vaccine Zostavax in humans. This study will add to our understanding of the role of antibodies in protection against shingles.

Current vaccines for the prevention of herpes zoster

PURPOSE OF REVIEW

To summarize the recent advances in the prevention of herpes zoster. The recent Food and Drug Administration (FDA) approval of an adjuvanted subunit vaccine may have a significant impact on the prevention of herpes zoster ophthalmicus.

RECENT FINDINGS

There are currently two commercially available vaccines for the prevention of herpes zoster: a live-attenuated vaccine and a new recombinant subunit vaccine. The latter has been shown to be more effective, have fewer contraindications, but requires two separate inoculations, has higher reactogenicity, and has only short-term postmarketing surveillance.

SUMMARY

The adjuvanted zoster subunit vaccine offers several advantages over the previously available vaccine. Following the current treatment recommendations, physicians should recommend vaccination to all patients older than 50 years of age with no contraindications, this should also prevent ophthalmic complications of the disease.

Reduced NK cell IFN-γ secretion and psychological stress are independently associated with herpes zoster

The pathogenesis of herpes zoster is closely linked to reduced varicella-zoster virus-specific cell-mediated immunity. However, little is known about the interplay between natural killer cells and psychological stress in the pathogenesis of herpes zoster. This study aimed to investigate possible associations among natural killer cells, T cells and psychological stress in herpes zoster. Interferon-gamma secretion from natural killer cell, psychological stress events, stress cognition scale scores and cytomegalovirus-specific cell-mediated immunity were compared between 44 patients with herpes zoster and 44 age- and gender-matched control subjects. A significantly lower median level of interferon-gamma secreted by natural killer cells was observed in patients with a recent diagnosis of herpes zoster than in control subjects (582.7 pg/ml vs. 1783 pg/ml; P = 0.004), whereas cytomegalovirus-specific cell-mediated immunity was not associated with herpes zoster. Psychological stress events and high stress cognition scale scores were significantly associated in patients with herpes zoster (P<0.001 and P = 0.037, respectively). However, reduced interferon-gamma secretion from natural killer cell and psychological stress were not associated. In conclusion, patients with a recent diagnosis of herpes zoster display reduced interferon-gamma secretion from natural killer cells and frequent previous psychological stress events compared with controls. However, reduced natural killer cell activity is not an immunological mediator between psychological stress and herpes zoster.

Age-Dependent Pre-Vaccination Immunity Affects the Immunogenicity of Varicella Zoster Vaccination in Middle-aged Adults

Background

Prevention of infectious diseases is of high priority in the rapidly aging population. Unfortunately, vaccine responses in the elderly are frequently diminished. Timely vaccination of middle-aged adults might improve the immune responses to vaccines, although knowledge on pathogen-specific immune responses and factors affecting these responses, in middle-aged adults is currently limited. We thus investigated the immune responses after vaccination with Zostavax consisting of live-attenuated varicella zoster virus (VZV).

Methods

Blood samples were taken pre-, 14 days, 28 days, and 1 year after a primary VZV vaccination (Zostavax) at middle age (N = 53, 50–65 years of age). VZV-specific IFNγ-producing cells were measured by ELISpot, activated T-cells by flow cytometry, antibody levels and cytokine responses by fluorescent bead-based multiplex immunoassays, and whole blood cellular kinetics by TruCOUNT analysis.

Results

Robust short-term enhancement of the VZV-specific IFNγ-producing cell numbers was observed post-vaccination in the middle-aged adults. Remarkably, long-term enhancement of VZV-specific IFNγ-producing cell numbers was induced only in participants with low numbers of VZV-specific pre-vaccination IFNγ-producing cells, who were significantly older. These participants also showed enhancement of VZV-specific activated CD4 T-cells, contrary to “exhausted” VZV-specific CD8 T-cells in participants with high numbers of VZV-specific pre-vaccination IFNγ-producing cells. Finally, a high CD4/CD8 T-cell ratio was associated with low numbers of pre-vaccination VZV-specific IFNγ-producing cells.

Conclusion

These results suggest that adults in their early sixties, who showed a high CD4/CD8 T-cell ratio and low numbers of VZV-specific IFNγ-producing cells, benefit from VZV vaccination. This provides important knowledge on factors affecting VZV-specific immune responses in middle-aged adults as well as for strategies to strengthen immunity before reaching old age.

Vaccines for the elderly: current use and future challenges

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

Immunogenicity and Safety of the HZ/su Adjuvanted Herpes Zoster Subunit Vaccine in Adults Previously Vaccinated With a Live Attenuated Herpes Zoster Vaccine

Background

Protection against herpes zoster (HZ) induced by the live attenuated zoster vaccine Zostavax (ZVL) wanes within 3–7 years. Revaccination may renew protection. We assessed whether (re)vaccination with the adjuvanted HZ subunit vaccine candidate (HZ/su) induced comparable immune responses in previous ZVL recipients and ZVL-naive individuals (HZ-NonVac).

Methods

In an open-label, multicenter study, adults ≥65 years of age, vaccinated with ZVL ≥5 years previously (HZ-PreVac), were matched to ZVL-naive adults (HZ-NonVac). Participants received 2 doses of HZ/su 2 months apart. The primary objective of noninferiority of the humoral immune response 1 month post–dose 2 was considered demonstrated if the upper limit of the 95% confidence interval (CI) of the adjusted anti–glycoprotein E geometric mean concentration (GMC) ratio of HZ-NonVac over HZ-PreVac was <1.5. HZ/su cellular immunogenicity, reactogenicity, and safety were also assessed.

Results

In 430 participants, humoral immune response to HZ/su was noninferior in HZ-PreVac compared with HZ-NonVac (adjusted GMC ratio, 1.04 [95% CI, .92–1.17]). Cellular immunogenicity, reactogenicity, and safety appeared to be comparable between groups. HZ/su was well-tolerated, with no safety concerns raised within 1 month post–dose 2.

Conclusions

HZ/su induces a strong immune response irrespective of prior vaccination with ZVL, and may be an attractive option to revaccinate prior ZVL recipients.

Clinical Trials Registration

NCT02581410.

Herpes Zoster in the Older Adult

Herpes zoster (HZ) is the result of reactivation of latent varicella zoster virus (VZV) and occurs most frequently in older adults. Classically, HZ presents as a unilateral, selflimited, dermatomal rash. Postherpetic neuralgia (PHN) is a common sequela, presenting as severe pain that persists after the rash has resolved. In the elderly, PHN can be debilitating and requires a prompt diagnosis, treatment with antivirals, and adequate pain control. A longer-term pain management strategy is required if PHN occurs. A modestly effective vaccine exists and is recommended for older individuals.

Cost Effectiveness of a Shingles Vaccine Booster for Currently Vaccinated Adults in the U.S

INTRODUCTION

The Advisory Committee on Immunization Practices recommends a single dose of the live attenuated herpes zoster vaccine in people aged ≥60 years. Because vaccine-induced protection decreases to zero after 10 years, many vaccinated people will soon be subject to an increased risk of the disease. The study objective was to determine the cost effectiveness of a herpes zoster vaccine booster and its optimal timing among immunocompetent adults first vaccinated at aged ≥60 years.

METHODS

A Markov model was built to follow vaccinated individuals for a lifetime. From the societal perspective, costs and quality-adjusted life years were compared between no booster versus booster options. A booster was given any time between 1 and 20 years after the first dose, and for those who had the first dose at different ages: 60, 70, and 80 years. Because people entered the model already vaccinated, costs and side effects of the first dose were not included. The booster was assumed to have the same efficacy and waning rate as the initial vaccination. Model inputs were based on published literature. A cost effectiveness threshold of $100,000/quality-adjusted life year was used. The analysis was conducted in 2016.

RESULTS

Cost effectiveness of a booster varied by age and time since vaccination. The booster cost <$100,000/quality-adjusted life year if given >5 years after the initial dose, but was most cost effective at around 10 years. The finding was robust to wide variations in model inputs.

CONCLUSIONS

Under current assumptions, a booster dose of herpes zoster vaccine would be cost effective for all vaccinated people 10 years after initial vaccination.

Varicella and herpes zoster vaccine development: lessons learned

INTRODUCTION

Before vaccination, varicella zoster virus (VZV), which is endemic worldwide, led to almost universal infection. This neurotropic virus persists lifelong by establishing latency in sensory ganglia, where its reactivation is controlled by VZV-specific T-cell immunity. Lifetime risk of VZV reactivation (zoster) is around 30%. Vaccine development was galvanised by the economic and societal burden of VZV, including debilitating zoster complications that largely affect older individuals. Areas covered: We describe the story of development, licensing and implementation of live attenuated vaccines against varicella and zoster. We consider the complex backdrop of VZV virology, pathogenesis and immune responses in the absence of suitable animal models and examine the changing epidemiology of VZV disease. We review the vaccines' efficacy, safety, effectiveness and coverage using evidence from trials, observational studies from large routine health datasets and clinical post-marketing surveillance studies and outline newer developments in subunit and inactivated vaccines. Expert commentary: Safe and effective, varicella and zoster vaccines have already made major inroads into reducing the burden of VZV disease globally. As these live vaccines have the potential to reactivate and cause clinical disease, developing alternatives that do not establish latency is an attractive prospect but will require better understanding of latency mechanisms.

Serum C-Reactive Protein and Congestive Heart Failure as Significant Predictors of Herpes Zoster Vaccine Response in Elderly Nursing Home Residents

Background

Elderly long-term care residents often exhibit a myriad of risk factors for immune dysfunction, including chronic inflammation and multiple comorbid conditions, which undoubtedly contribute to their enhanced susceptibility to infection. Hence, understanding the factors required for optimal vaccine responsiveness is critical.

Methods

We examined 187 elderly nursing home residents (aged 80-102 years) and 50 community-dwelling seniors (aged 60-75 years) immunized with the live-attenuated varicella-zoster virus (VZV) vaccine. Specifically, we examined whether vaccine responsiveness was associated with serum C-reactive protein (CRP), tumor necrosis factor, interleukin 1β, 6, and 10, leukocyte telomere length, chronic disease status, and frailty.

Results

Elderly participants had significantly higher levels of CRP, tumor necrosis factor, and interleukin 6 and shorter leukocyte telomere length. Vaccine responsiveness was inversely related to the CRP level in elderly participants, but not seniors, and those with congestive heart failure were less likely to achieve a 2-fold response (odds ratio, 0.08). The latter relationship is probably due to immunosenescence, because heart failure was associated with increased senescent CD4+ T cells, and reduced naive and effector and central memory CD8+ T cells.

Conclusions

In summary, these data improve our understanding of vaccine responsiveness for those in long-term care, suggesting that certain risk factors are associated with a greater likelihood of vaccine failure.

Immunogenicity and safety of zoster vaccine live administered with quadrivalent influenza virus vaccine

OBJECTIVES

Randomized, blinded, placebo-controlled trial to evaluate the safety and immunogenicity of ZOSTAVAX™ (ZV) administered concomitantly with quadrivalent inactivated influenza vaccine (IIV4) in adults≥50years of age (NCT02519855).

METHODS

Overall, 440 participants were randomized into the Concomitant Group (CG) and 442 into the Sequential Group (SG). The CG received ZV and IIV4 at separate injection sites on Day 1 and matching placebo at Week 4. The SG received placebo and IIV4 (2015-2016 influenza season) at separate injection sites on Day 1 and ZV at Week 4.

IMMUNOGENICITY ENDPOINTS

Varicella-zoster virus (VZV) antibody geometric mean titer (GMT) and geometric mean fold-rise (GMFR) from baseline to 4weeks postvaccination, measured by glycoprotein enzyme-linked immunosorbent assay (gpELISA) and adjusted for age and prevaccination titer. Influenza strain-specific GMT at baseline and 4weeks postvaccination was measured by hemagglutination inhibition (HAI) assay.

SAFETY ENDPOINTS

Injection-site and systemic adverse experiences (AEs) within 28days following any vaccination and serious AEs throughout the study.

RESULTS

The adjusted VZV antibody GMT ratio (CG/SG) was 0.87 (95%CI: 0.80, 0.95), meeting the prespecified noninferiority criterion. The VZV antibody GMFR in the CG was 1.9 (95%CI: 1.76, 2.05), meeting the acceptability criterion. Influenza antibody GMT ratios for A/H1N1, A/H3N2, B/Yamagata and B/Victoria were 1.02 (95%CI: 0.88, 1.18), 1.10 (95%CI: 0.94, 1.29), 1.00 (95%CI: 0.88, 1.14), and 0.99 (95%CI: 0.87, 1.13), respectively. The frequency of vaccine-related injection-site and systemic AEs was comparable between groups. No vaccine-related serious AE was observed.

CONCLUSION

The concomitant administration of ZV and IIV4 to adults≥50years of age induced VZV-specific and influenza-specific antibody responses that were comparable to those following administration of either vaccine alone, and was generally well tolerated.

Varicella-Zoster Virus-Specific Cellular Immune Responses to the Live Attenuated Zoster Vaccine in Young and Older Adults

The incidence and severity of herpes zoster (HZ) increases with age. The live attenuated zoster vaccine generates immune responses similar to HZ. We compared the immune responses to zoster vaccine in young and older to adults to increase our understanding of the immune characteristics that may contribute to the increased susceptibility to HZ in older adults. Young (25-40 y; n = 25) and older (60-80 y; n = 33) adults had similar magnitude memory responses to varicella-zoster virus (VZV) ex vivo restimulation measured by responder cell-frequency and flow cytometry, but the responses were delayed in older compared with young adults. Only young adults had an increase in dual-function VZV-specific CD4⁺ and CD8⁺ T cell effectors defined by coexpression of IFN-γ, IL-2, and CD107a after vaccination. In contrast, older adults showed marginal increases in VZV-specific CD8⁺CD57⁺ senescent T cells after vaccination, which were already higher than those of young adults before vaccination. An increase in VZV-stimulated CD4⁺CD69⁺CD57⁺PD1⁺ and CD8⁺CD69⁺CD57⁺PD1⁺ T cells from baseline to postvaccination was associated with concurrent decreased VZV-memory and CD8⁺ effector responses, respectively, in older adults. Blocking the PD1 pathway during ex vivo VZV restimulation increased the CD4⁺ and CD8⁺ proliferation, but not the effector cytokine production, which modestly increased with TIM-3 blockade. We conclude that high proportions of senescent and exhausted VZV-specific T cells in the older adults contribute to their poor effector responses to a VZV challenge. This may underlie their inability to contain VZV reactivation and prevent the development of HZ.