Increasing incidence associated with herpes zoster infection in British Columbia, Canada

Attitudes, barriers, and facilitators to adherent completion of the recombinant zoster vaccine regimen in Canada: Qualitative interviews with healthcare providers and patients

This qualitative, cross-sectional study aimed to understand the barriers and facilitators related to the adherence and completion of the recombinant zoster vaccine (RZV) two-dose series in Canada, as perceived by healthcare providers (HCPs) and patients. Data collection occurred via 60-minute concept elicitation interviews with 12 HCPs (4 physicians, 2 nurse practitioners, 6 pharmacists) who had prescribed and/or administered RZV in Canada, and 21 patients aged ≥50 years who had received ≥1 dose of RZV. Patients were categorized as adherent (received both doses within the recommended 2-to-6-month timeframe; n = 11) or non-adherent (received only one dose or second dose outside the recommended timeframe; n = 10). Interview transcripts were coded and analyzed using a two-part thematic analysis approach. HCP-identified barriers to RZV adherence included high out-of-pocket cost, inconsistent/lack of health plan coverage, inconvenient processes for accessing RZV, and patient forgetfulness. HCP-identified facilitators included desire for shingles protection, HCP encouragement, and reminders. Barriers to RZV adherence identified by patients included lack of HCP knowledge/experience with RZV, receiving unreliable/confusing information, having unpleasant/severe side effects following the first dose, high out-of-pocket cost, lack of insurance coverage, and forgetfulness. Patient-identified facilitators included self-motivation, financial support, convenient processes for obtaining RZV, and reminders. In conclusion, many factors can influence RZV series completion and adherence among adults in Canada, including cost, insurance coverage, HCP knowledge and encouragement, and reminders. Awareness of these factors may inform HCPs in helping patients overcome barriers and identify opportunities for future consideration, facilitating protection against herpes zoster.

Association of the incidence of postherpetic neuralgia with early treatment intervention of herpes zoster and patient baseline characteristics: A systematic review and meta-analysis of cohort studies

OBJECTIVES

To conduct a meta-analysis of the association between postherpetic neuralgia (PHN), baseline characteristics of patients with herpes zoster (HZ), and early interventions.

METHODS

Literature searches were conducted in seven databases, in June 2021 and updated in June 2022. Two investigators independently conducted literature screening and data extraction, and the studies were evaluated according to the Newcastle-Ottawa scale.

RESULTS

A total of 53 cohort studies were included. The meta-analyses identified skin lesions, timing of initial treatment (≥3 days), and comorbidities as potential risk factors for PHN. In contrast, female sex (odds ratio [OR] = 1.13, 95% confidence interval [CI]: 0.99-1.29), cervical herpes (OR = 0.80, 95% CI: 0.21-2.99), lumbar herpes (OR = 1.29, 95% CI: 0.61-2.74), and immunosuppressive therapy (OR = 1.96, 95% CI: 0.22-17.12), were not significantly associated with PHN. In addition, glucocorticoid use (OR = 0.61, 95% CI: 0.22-1.70) may be a protective factor for the development of PHN; however, the difference was not statistically significant.

CONCLUSION

A series of baseline characteristics were identified among populations at high risk of developing PHN from HZ. Additionally, the timing of initial treatment is associated with PHN occurrence. The preventive effect of glucocorticoids warrants further validation.

The Incidence of Herpes Zoster Complications: A Systematic Literature Review

INTRODUCTION

The objective of this work was to summarize the incidence of herpes zoster (HZ) complications in different populations.

METHODS

Systematic literature review of PubMed, Embase, and Virtual Health Library records between January 1, 2002 and October 20, 2022 using search strings for HZ, complications, and frequency measurements.

RESULTS

The review included 124 studies, most conducted in the general population (n = 93) and on individuals with comorbidities (n = 41) ≥ 18 years of age. Most studies were conducted in Europe (n = 44), Asia (n = 40), and North America (n = 36). Postherpetic neuralgia (PHN) was the most studied neurological complication. Variable relative PHN incidence was found in the general population (2.6-46.7%) or based on diagnosis: immunocompromised (3.9-33.8%), depression (0-50%), and human immunodeficiency virus (HIV) (6.1-40.2%). High incidence rates were observed in hematological malignancies (HM) and solid organ malignancies (132.5 and 93.7 per 1000 person-years, respectively). Ocular complications were frequently reported with herpes zoster ophthalmicus (HZO). The relative incidence (incidence rate) of HZO in the general population was reported as 1.4-15.9% (0.31-0.35 per 1000 person-years). High relative incidence was observed in HIV (up to 10.1%) and HM (3.2-11.3%). Disseminated HZ was the most frequently reported cutaneous complication. The relative incidence of disseminated HZ was 0.3-8.2% in the general population, 0-0.5% in the immunocompetent, and 0-20.6% in patients with comorbidities. High relative incidence was reported in HM and solid organ transplant (up to 19.3% and 14.8%, respectively).

DISCUSSION

Most reported complications were neurological (n = 110), ocular (n = 48), and cutaneous (n = 38). Few studies stratified complications by age or gender (or both). Incidence appeared higher in select immunocompromised populations. Higher incidence was associated with older age in several studies; the general association with gender was unclear.

CONCLUSIONS

Variable incidence of HZ complications was reported by population subgroup. Further research is required to quantitatively analyze incidence by age, gender, and location.

Perceptions, Attitudes, Beliefs, and Practices Toward Traditional Chinese Medicine Therapies for Herpes Zoster: A Cross-Sectional Study of Healthcare Professionals

Introduction

Traditional Chinese medicine (TCM) holds great potential in promoting healing and relieving pain for herpes zoster (HZ) treatments. Evidence showed that both healthcare professionals' (HCPs) belief and knowledge influence their attitudes, which result in their expression and direct behavior. However, little is known in this area regarding TCM treatments for HZ. This study aimed to understand the HCPs' perceptions, attitudes, beliefs, and practices toward TCM and its services for HZ.

Methods

During July 2021 and October 2022, a cross-sectional study of HCPs querying demographics, perceptions, attitudes, beliefs, and practices toward TCM and TCM services for HZ was conducted. The frequency and percentage or mean and standard deviation were used to present categorical data and continuous data, respectively. A Chi-square analysis compared nurses' and doctors' views on TCM treatments for HZ.

Results

Out of 306 eligible respondents, 66.0% used TCM content in clinical practice less than 40% of the time. Respondents reported that there were three main advantages of TCM for HZ, including better crusting and healing, fewer side effects, and mitigating complications. A total of 41.3% (81/196) of the respondents who had cared for/treated HZ patients applied TCM treatments. The three factors most associated with referrals/providing TCM to patients were postherpetic neuralgia, early erythema or papules, and acute pain. Compared to nurses, doctors showed more endorsement of the efficacy and cost-effectiveness of TCM treatments for HZ patients.

Conclusion

The study found that most healthcare professionals in HZ had a favorable view of TCM, but lacked practical experience administering it to patients. Programs should be developed to provide evidence-based TCM treatments and encourage combining TCM with Western medicine for better patient care.

Updated Public Health Impact and Cost Effectiveness of Recombinant Zoster Vaccine in Canadian Adults Aged 50 Years and Older

OBJECTIVES

The aim of this study was to update previously estimated public health impact and cost effectiveness of recombinant zoster vaccine (RZV) for the prevention of herpes zoster (HZ) in Canadians aged ≥50 years using longer-term RZV efficacy and waning data and real-world coverage and completion.

METHODS

A multicohort Markov model was used to conduct a cost-utility analysis comparing RZV with no HZ vaccination among Canadians aged ≥50 years. Real-world data were used for first-dose coverage (17.5%) and second-dose completion (65%). Vaccine efficacy and waning data were applied from up to 8-year follow-up from the ZOE-50 and ZOE-70 clinical trials. Incremental costs and benefits were calculated using a lifetime horizon from the healthcare payer (base case) and societal perspectives. A discount rate of 1.5% was applied to costs and quality-adjusted life-years (QALYs).

RESULTS

The model estimated that RZV would prevent 303,835 HZ cases, 83,256 post-herpetic neuralgia (PHN) cases, 39,653 other complications, and 99 HZ-related deaths compared with no HZ vaccination. Incremental cost-effectiveness ratios (ICERs) were estimated to be $27,486 and $22,097 per QALY (2022 Canadian dollars [CAN$]) from the healthcare payer and societal perspectives, respectively. The base-case ICER was most sensitive to a lower percentage of initial HZ cases with PHN. Almost all probabilistic sensitivity analysis simulations (98.1%) resulted in ICERs

CONCLUSIONS

RZV is expected to remain a cost-effective option for Canadian adults aged ≥50 years when using longer-term RZV efficacy and waning estimates, although the estimated public health impact was smaller than in the previous analysis (due to lower coverage/completion estimates).

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Grants

• GlaxoSmithKline Biologicals

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Affiliation(s)

Sydney George GSK, Mississauga, ON, Canada.
Justin Carrico RTI Health Solutions, Research Triangle Park, NC, USA
Katherine A Hicks RTI Health Solutions, Research Triangle Park, NC, USA
Dessi Loukov GSK, Mississauga, ON, Canada
Cheryl Ng GSK, Singapore, Singapore
Jessica Regan GSK, Mississauga, ON, Canada
Nikolaos Giannelos GSK, Wavre, Belgium

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Cost-effectiveness of the recombinant zoster vaccine (RZV) against herpes zoster: An updated critical review

The objective of this study was to critically review the cost-effectiveness (CE) of the recombinant zoster vaccine (RZV) against herpes zoster (HZ). A literature review was conducted in PubMed, Embase, and Cochrane between January 1, 2017, and February 28, 2022, and on select public healthcare agency websites to identify and collect data from CE studies comparing RZV to zoster vaccine live (ZVL) or to no vaccination. Study characteristics, inputs, and outputs were collected. The overall CE of RZV was assessed. RZV vaccination against HZ is cost-effective in 15 out of 18 studies included in the present review. Varying incremental cost-effectiveness ratios (ICERs) observed may be associated with different assumptions on the duration of protection of RZV, as well as different combinations of structural and disease-related study (model) inputs driving the estimation of ICERs.

Vaccines for preventing herpes zoster in older adults

BACKGROUND

Herpes zoster, commonly known as shingles, is a neurocutaneous disease caused by the reactivation of the virus that causes varicella (chickenpox). After resolution of the varicella episode, the virus can remain latent in the sensitive dorsal ganglia of the spine. Years later, with declining immunity, the varicella zoster virus (VZV) can reactivate and cause herpes zoster, an extremely painful condition that can last many weeks or months and significantly compromise the quality of life of the affected person. The natural process of ageing is associated with a reduction in cellular immunity, and this predisposes older adults to herpes zoster. Vaccination with an attenuated form of the VZV activates specific T-cell production avoiding viral reactivation. Two types of herpes zoster vaccines are currently available. One of them is the single-dose live attenuated zoster vaccine (LZV), which contains the same live attenuated virus used in the chickenpox vaccine, but it has over 14-fold more plaque-forming units of the attenuated virus per dose. The other is the recombinant zoster vaccine (RZV) which does not contain the live attenuated virus, but rather a small fraction of the virus that cannot replicate but can boost immunogenicity. The recommended schedule for the RZV is two doses two months apart. This is an update of a Cochrane Review first published in 2010, and updated in 2012, 2016, and 2019.

OBJECTIVES

To evaluate the effectiveness and safety of vaccination for preventing herpes zoster in older adults.

SEARCH METHODS

For this 2022 update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL 2022, Issue 10), MEDLINE (1948 to October 2022), Embase (2010 to October 2022), CINAHL (1981 to October 2022), LILACS (1982 to October 2022), and three trial registries.

SELECTION CRITERIA

We included studies involving healthy older adults (mean age 60 years or older). We included randomised controlled trials (RCTs) or quasi-RCTs comparing zoster vaccine (any dose and potency) versus any other type of intervention (e.g. varicella vaccine, antiviral medication), placebo, or no intervention (no vaccine). Outcomes were cumulative incidence of herpes zoster, adverse events (death, serious adverse events, systemic reactions, or local reaction occurring at any time after vaccination), and dropouts.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included two new studies involving 1736 participants in this update. The review now includes a total of 26 studies involving 90,259 healthy older adults with a mean age of 63.7 years. Only three studies assessed the cumulative incidence of herpes zoster in groups that received vaccines versus placebo. Most studies were conducted in high-income countries in Europe and North America and included healthy Caucasians (understood to be white participants) aged 60 years or over with no immunosuppressive comorbidities. Two studies were conducted in Japan and one study was conducted in the Republic of Korea. Sixteen studies used LZV. Ten studies tested an RZV. The overall certainty of the evidence was moderate, which indicates that the intervention probably works. Most data for the primary outcome (cumulative incidence of herpes zoster) and secondary outcomes (adverse events and dropouts) came from studies that had a low risk of bias and included a large number of participants. The cumulative incidence of herpes zoster at up to three years of follow-up was lower in participants who received the LZV (one dose subcutaneously) than in those who received placebo (risk ratio (RR) 0.49, 95% confidence interval (CI) 0.43 to 0.56; risk difference (RD) 2%; number needed to treat for an additional beneficial outcome (NNTB) 50; moderate-certainty evidence) in the largest study, which included 38,546 participants. There were no differences between the vaccinated and placebo groups for serious adverse events (RR 1.08, 95% CI 0.95 to 1.21) or deaths (RR 1.01, 95% CI 0.92 to 1.11; moderate-certainty evidence). The vaccinated group had a higher cumulative incidence of one or more adverse events (RR 1.71, 95% CI 1.38 to 2.11; RD 23%; number needed to treat for an additional harmful outcome (NNTH) 4.3) and injection site adverse events (RR 3.73, 95% CI 1.93 to 7.21; RD 28%; NNTH 3.6; moderate-certainty evidence) of mild to moderate intensity. These data came from four studies with 6980 participants aged 60 years or older. Two studies (29,311 participants for safety evaluation and 22,022 participants for efficacy evaluation) compared RZV (two doses intramuscularly, two months apart) versus placebo. Participants who received the new vaccine had a lower cumulative incidence of herpes zoster at 3.2 years follow-up (RR 0.08, 95% CI 0.03 to 0.23; RD 3%; NNTB 33; moderate-certainty evidence), probably indicating a favourable profile of the intervention. There were no differences between the vaccinated and placebo groups in cumulative incidence of serious adverse events (RR 0.97, 95% CI 0.91 to 1.03) or deaths (RR 0.94, 95% CI 0.84 to 1.04; moderate-certainty evidence). The vaccinated group had a higher cumulative incidence of adverse events, any systemic symptom (RR 2.23, 95% CI 2.12 to 2.34; RD 33%; NNTH 3.0), and any local symptom (RR 6.89, 95% CI 6.37 to 7.45; RD 67%; NNTH 1.5). Although most participants reported that their symptoms were of mild to moderate intensity, the risk of dropouts (participants not returning for the second dose, two months after the first dose) was higher in the vaccine group than in the placebo group (RR 1.25, 95% CI 1.13 to 1.39; RD 1%; NNTH 100, moderate-certainty evidence). Only one study reported funding from a non-commercial source (a university research foundation). All other included studies received funding from pharmaceutical companies. We did not conduct subgroup and sensitivity analyses AUTHORS' CONCLUSIONS: LZV (single dose) and RZV (two doses) are probably effective in preventing shingles disease for at least three years. To date, there are no data to recommend revaccination after receiving the basic schedule for each type of vaccine. Both vaccines produce systemic and injection site adverse events of mild to moderate intensity. The conclusions did not change in relation to the previous version of the systematic review.

The Role of Sex and Gender in Dermatology - From Pathogenesis to Clinical Implications

BACKGROUND

Sex and gender have increasingly been recognized as significant risk factors for many diseases, including dermatological conditions. Historically, sex and gender have often been grouped together as a single risk factor in the scientific literature. However, both may have a distinct impact on disease incidence, prevalence, clinical presentation, severity, therapeutic response, and associated psychological distress.

OBJECTIVES AND PROJECT DESCRIPTION

The mechanisms that underlie differences in skin diseases between males, females, men, and women remain largely unknown. The specific objectives of this review paper are:To highlight the biological differences between males and females (sex), as well as the sociocultural differences between men and women (gender) and how they impact the integumentary system.To perform a literature review to identify important sex- and gender-related epidemiological and clinical differences for various skin conditions belonging to a range of disease categories and to discuss possible biological and sociocultural factors that could explain the observed differences.To discuss dermatological skin conditions and gender-affirming treatments within the transgender community, a population of individuals who have a gender identity which is different than the gender identity they were assigned at birth.

FUTURE IMPACT

With the rising number of individuals that identify as non-binary or transgender within our increasingly diverse communities, it is imperative to recognize gender identity, gender, and sex as distinct entities. By doing so, clinicians will be able to better risk-stratify their patients and select treatments that are most aligned with their values. To our knowledge, very few studies have separated sex and gender as two distinct risk factors within the dermatology literature. Our article also has the potential to help guide future prevention strategies that are patient-tailored rather than using a universal approach.

Surveying a Sample of the Spanish Ophthalmologic Community about Vaccination against Herpes Zoster

There are currently two authorized vaccines against herpes zoster (HZ) that have been shown to be safe and effective in its prevention: Zostavax, a zoster vaccine live (ZVL), and Shingrix, a recombinant zoster Vaccine (RZV). Because ophthalmologists work with vision-threatening complications of zoster, such as herpes zoster ophthalmicus (HZO), they are in a good position to advocate for vaccination. Our aim was to determine the current knowledge among Spanish ophthalmologists about the effectiveness of the available vaccines against HZ. A Google Forms questionnaire was created and used as the survey platform for this study. It was an anonymous online survey of 16 questions, which was shared among Spanish ophthalmologists in-training and consultants from 27 April 2022 to 25 May 2022. The survey was completed by a total of 206 ophthalmologists of all subspecialties. We obtained responses from 17 of the 19 regions of Spain. Fifty-five percent of the respondents agreed that HZ is a frequent cause of vision loss. However, 27% of the professionals were unaware of the existence of vaccines against HZ and 71% of them did not know in which cases it could be indicated. Only nine ophthalmologists (4%) had ever suggested vaccination against HZ to their patients. Despite this, 93% considered it important to recommend vaccination against HZ if it proved to be safe and effective. Considering the sequelae, complications, and the existence of safe and effective vaccines against HZ, vaccination of the target population could be considered an important public health measure. We are convinced that it is time for ophthalmologists to take an active role in HZO prevention.

Association between Meteorological Factors and Outpatient Visits for Herpes Zoster in Hefei, China: A Time-Series Analysis

This study sought to investigate the relationship between meteorological factors and outpatient visits for herpes zoster. In this time-series analysis, we used data from two major hospitals in Hefei, collected between 2015 and 2019, to evaluate the impact of meteorological factors on the risk of herpes zoster. After controlling for confounders, we adopted a distributed lag nonlinear model to probe the relationship between meteorological factors and outpatient visits for herpes zoster. The analysis was stratified according to age (<40 years, ≥40 years) and sex (male, female). A total of 43,547 cases of herpes zoster were reported, and compared with the median value, a high temperature and high relative humidity had a significant risk effect on the incidence of herpes zoster. The maximum harmful effect of high temperature on herpes zoster occurred on the lag0 (RR: 1.027, 95% CI: 1.002-1.053) and further declined over the following days. The cumulative effect increased with the extension of lag days, and the cumulative RR was the largest on the sixth day of lag (RR1.031, 95% CI: 1.006-1.056) when the relative humidity was 85.7% (77.0% as the reference). The stratified analysis results reveal that females and the elderly (≥40 years) were more susceptible to temperature and relative humidity. This study shows that high-temperatures may lead to herpes zoster, indicating that those infected with varicella zoster virus need to take measures over the course of several days when not exposed to the best appropriate temperature conditions.

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.

Prevention of Herpes Zoster: A Focus on the Effectiveness and Safety of Herpes Zoster Vaccines

Infection with varicella zoster virus typically occurs in children and it can cause primary varicella infection or "chickenpox", or it can reactivate later in life and cause herpes zoster or "shingles". Herpes zoster mainly occurs in older adults, causing a reduction in activities of daily living, impacting quality of life, and may lead to serious complications, including chronic pain. Two vaccines are marketed to prevent herpes zoster: the live zoster vaccine and the non-live, recombinant zoster vaccine. The pre-licensure clinical trials show the efficacy of the live zoster vaccine to be between 50 and 70% and for the recombinant vaccine to be higher at 90 to 97%. Real-world effectiveness studies, with a follow-up of approximately 10 years, were reviewed in this article. These data corroborated the efficacy studies, with vaccine effectiveness being 46% and 85% for the live and recombinant vaccines, respectively. Safety data from the effectiveness studies show similar results to the clinical trials with mostly local injection-site reactions and mild systemic reactions seen with both vaccines, although in larger proportions with the recombinant vaccine. Rare adverse events, occurring less than 1% of the time, have been seen with both vaccine types and include disseminated herpes zoster with the live zoster vaccine and Guillain-Barré syndrome with the recombinant vaccine. The wider use of preventative measures with vaccines will reduce the herpes zoster burden of illness seen in older adults.

The Impact of Universal Varicella Vaccination on Herpes Zoster Incidence in the United States: Comparison of Birth Cohorts Preceding and Following Varicella Vaccination Program Launch

When the US varicella vaccination program was introduced in 1995, its impacts on the epidemiology of herpes zoster (HZ) were not precisely known. We used a large claims database to examine HZ incidence in the US during 1998-2019 among persons aged ≥30 years (the prevaccine cohort, born before 1990), and aged 1-29 years (includes the postvaccine cohort, born since 1990). We defined incident HZ as the first instance of an outpatient or emergency department (ED) claim with an HZ diagnostic code. Additionally, we examined the proportion of HZ visits among all ED visits as a complementary method to assess for healthcare-seeking artifacts in the findings. In persons aged ≥30 years (prevaccine cohort), we observed age-specific increases in HZ incidence during the earlier study years, with decelerations in later years, starting in 2007 with oldest age groups. Similar patterns were seen when we examined HZ visits as a proportion of all ED visits. For persons aged 1-29 years, age-specific HZ incidence increased early in the study period for the oldest age groups who were born prevaccine, but later declined in a stepwise pattern once each age group was comprised of persons born in the postvaccine period. Our results, corroborated with previously published studies, do not support prior modeling predictions that the varicella vaccination program would increase HZ incidence among adult cohorts who previously experienced varicella. Our findings also suggest that continued declines in age-specific HZ incidence as varicella-vaccinated cohorts age are likely.

Sero-positivity, risks, and morbidity from Varicella-Zoster Virus (VZV) infections in an adult PWH (people with HIV) cohort from 2000-2020

Background

Varicella-zoster virus (VZV) infection disproportionately affects people with HIV (PWH), primarily presenting as herpes zoster. However, VZV seroprevalence, its association with zoster, and clinical outcomes remain understudied in era of modern antiretroviral therapy (ART). We assessed VZV seroprevalence, rates of VZV illness, and associated health care costs in a large cohort of PWH over 20 years.

Methods

We performed retrospective chart reviews of patients followed at a regional HIV clinic from January 1, 2000, to December 31, 2020. Serological, immunization, clinical, and costing data were extracted from in-house databases. VZV-related inpatient admissions, emergency department (ED), and urgent care (UC) visits were identified using relevant International Classification of Disease (ICD-10) codes and validated where possible by 2 physicians. Health care utilization costs were adjusted to 2020 Canadian dollars.

Results

Of 3006 PWH, VZV serology was available for 2628; of these, 2503 (95.2%) were seropositive. Only 39% of known seronegative patients were subsequently immunized for varicella. During 29 768 years of patient follow-up, 38 hospitalizations and 138 ED/UC visits due to VZV infection were identified. Most occurred in VZV-seropositive PWH <50 years of age (82%) who were unimmunized (99.2%) and not on ART (64.8%). Nearly 25% of hospitalizations were due to laboratory-confirmed VZV meningitis/encephalitis. The average admission cost was CDN$33 001; the total measured cost of VZV illness was CDN$1 258 718.

Conclusions

Despite ART and vaccines for chickenpox and shingles, VZV still caused significant costs and morbidity for PWH, occurring at younger ages and often as encephalitis/meningitis. Supporting ART adherence may reduce VZV illness and hospitalization costs in PWH, and the cost-effectiveness of expanding shingles vaccine use warrants further study.

Infectious keratitis: A review

Globally, infectious keratitis is the fifth leading cause of blindness. The main predisposing factors include contact lens wear, ocular injury and ocular surface disease. Staphylococcus species, Pseudomonas aeruginosa, Fusarium species, Candida species and Acanthamoeba species are the most common causal organisms. Culture of corneal scrapes is the preferred initial test to identify the culprit organism. Polymerase chain reaction (PCR) tests and in vivo confocal microscopy can complement the diagnosis. Empiric therapy is typically commenced with fluoroquinolones, or fortified antibiotics for bacterial keratitis; topical natamycin for fungal keratitis; and polyhexamethylene biguanide or chlorhexidine for acanthamoeba keratitis. Herpes simplex keratitis is mainly diagnosed clinically; however, PCR can also be used to confirm the initial diagnosis and in atypical cases. Antivirals and topical corticosteroids are indicated depending on the corneal layer infected. Vision impairment, blindness and even loss of the eye can occur with a delay in diagnosis and inappropriate antimicrobial therapy.

Comparing Prodrugs with Acyclovir for Treating Postherpetic Neuralgia among Herpes Zoster Patients: A Systematic Review and Meta-Analysis

Postherpetic neuralgia (PHN) is a common, painful, and long-term complication of herpes zoster (HZ). PHN increases the demand for healthcare services and, previous studies showed that patients who received antiviral agents were less likely to develop PHN. The objective of this study was to compare the efficacy of prodrugs and acyclovir in treating PHN among patients with HZ. The search included the PubMed, Medline, Embase, and Cochrane Center of Register of Controlled Trails databases through February 2022. Clinical trials and randomized controlled trials (RCTs) involving antiviral agent intervention for HZ patients diagnosed with PHN were eligible for inclusion. A meta-analysis was conducted to calculate pooled risk ratios (RRs) with 95% confidence intervals (CIs) with a fix-effect model. Five RCTs with 1147 HZ patients met our eligibility criteria. Our meta-analysis found that there was a significantly lower risk of PHN for members of the prodrugs group (famciclovir and valaciclovir) compared with those who received acyclovir (RR = 0.86, 95%, CI: 0.75 to 0.98, p = 0.03). The review of studies indicated that the efficacy of prodrugs was better than acyclovir for reliving PHN.

No consistent evidence of decreased exposure to varicella-zoster virus among older adults in countries with universal varicella vaccination

Background

Universal varicella vaccination might reduce opportunities for varicella-zoster virus (VZV) exposure and protective immunological boosting, thus increasing herpes zoster incidence in latently infected adults. We assessed humoral and cell-mediated immunity (CMI), as markers of VZV exposure, in adults aged ≥50 years.

Methods

We repurposed data from placebo recipients in a large multinational clinical trial (ZOE-50). Countries were clustered based on their varicella vaccination program characteristics, as having high, moderate, or low VZV circulation. Anti-VZV antibody geometric mean concentrations, median frequencies of VZV-specific CD4 T cells, and percentages of individuals with increases in VZV-specific CD4 T-cell frequencies were compared across countries and clusters. Sensitivity analyses using a variable number of time points and different thresholds were performed for CMI data.

Results

VZV-specific humoral immunity from 17 countries (12 high, 2 moderate, 3 low circulation) varied significantly between countries (P < .0001) but not by VZV circulation. No significant differences were identified in VZV-specific CMI between participants from 2 high versus 1 low circulation country. In 3/5 sensitivity analyses, increases in CMI were more frequent in high VZV circulation countries (.03 ≤ P < .05).

Conclusions

We found no consistent evidence of reduced VZV exposure among older adults in countries with universal varicella vaccination.

Clinical Trials Registration

NCT01165177.

Validation of algorithms using International Classification of Diseases for the identification of herpes zoster episodes requiring hospitalization in Quebec, Canada

OBJECTIVE

We determined secular changes in the incidence of hospitalizations due to herpes zoster (HZh) and assessed the validity of HZ International Classification of Diseases (ICD) code algorithms for identifying HZh in a region of Quebec, Canada.

METHODS

We performed a validation study as part of a retrospective cohort study of adult HZ patients hospitalized at Centre Hospitalier Universitaire de Sherbrooke during 2000-2017. Cases were identified using ICD codes from an inpatient administrative database. HZ cases identified by ICD-9 (053.xx) and ICD-10 (B02.x) codes were chart-confirmed, and performance characteristics of ICD code algorithms were calculated (positive predictive value [PPV] and sensitivity).

RESULTS

Overall, 1314 hospitalizations with HZ diagnosis (HZh) with or without complications were identified during 2000-2017. Among the hospitalizations, 526 (44.4%) were due to active HZ disease or a complication related to a recent or previous HZ episode. These hospitalizations were due to active disease at the time of admission (340/526, 64.6%), HZ that developed during hospitalization (120/526, 22.8%), or a complication directly related to a recent or previous HZ episode (66/526, 12.6%). PPV was significantly higher when HZ was the primary diagnosis (276/310, 89%, 95% confidence interval [CI]: 85-92%) than when HZ was a secondary diagnosis (254/928, 27%, 95% CI: 25-30%) (p < 0.0001), and the PPV of a first secondary diagnosis (84/140, 60.0%, 95% CI: 51.3-68.2%) was higher than that of other secondary diagnoses (203/794, 25.6%, 95% CI: 22.6-28.8%) (p < 0.0001). An algorithm combining ICD codes and antiviral usage demonstrated the best sensitivity (86.3%, 95% CI: 83.1-89.1%) and PPV to identify HZh (100%, 95% CI: 99.2-100%). Poisson regression revealed no significant changes in HZh over time (incidence rate ratio: 0.98, 95% CI: 0.92-1.04%; p = 0.5).

CONCLUSION

HZh incidence was stable over time. Prescription of antivirals might be a useful addition to ICD codes to identify HZh cases from administrative databases.

Are patients with rheumatic diseases on immunosuppressive therapies protected against preventable infections? A cross-sectional cohort study

Objective

To evaluate the prevalence of infections, prevalence of hospitalisation due to infections, the vaccination status and perceived screening of infections prior to the start of biologic disease modifying antirheumatic drugs (bDMARDs) of a patient cohort with chronic inflammatory rheumatic diseases (CIRD).

Methods

Consecutive CIRD patients reporting to our specialised centre were prospectively included (n=975) in this cross-sectional study. Data on comorbidities including infections, treatment, vaccination status, screening for latent tuberculosis infection (LTBI) and hepatitis B (HepB) were collected. Antibodies against measles and HepB were measured by ELISA. The vaccination status was assessed by a predefined vaccination score (0–26) categorising patients into four immunisation states: low (0–6), moderate (7–13), good (14–20), high (21–26).

Results

All patients on bDMARDs (n=499) were screened for LTBI, and 469 for HepB (94%). All LTBI patients (n=16) received isoniazid (3.2%) and 16 chronic HepB patients received lamivudine (3.4%). Protective measles specific IgG-antibodies were found in 901 patients (92.4%). Although 629 patients were educated about vaccination strategies (64.5%), only 540 showed a vaccination card (55.4%). Only 49% of patients had undergone pneumococcal vaccination and less than 30% were protected against HepB and influenza, while 7.6% have not protective antibody titres against measles. No patient met the German national vaccination recommendations requiring a complete documentation of vaccines. The mean vaccination score was 13.3±4.2 with 5.7% of patients having a low, 43.9% a moderate, 47.0% a good and 3.3% a high score.

Conclusions

The majority of CIRD patients are n0t sufficiently vaccinated against pneumococci, HepB, influenza and measles. Although CIRD patients and general practitioners regularly receive professional information about the need of vaccination, vaccination rates were low to moderate. Interdisciplinary quality projects should be planned to change that inacceptable result.

The impact of varicella vaccination on paediatric herpes zoster epidemiology: a Canadian population-based retrospective cohort study

The impact of universal varicella vaccination on herpes zoster (HZ) risk in unvaccinated and vaccinated children, and its long-term influence on HZ epidemiology, remains unknown. We conducted a retrospective cohort study using population-based administrative health data for children born between 1993 and 2018 (n = 924,124). We calculated age-specific cumulative HZ incidence rates by vaccination status for cohorts born before (1993–1999) and after (2000–2018) programme implementation; results were used to calculate relative risk of HZ by age group, vaccination status and vaccine availability period. Annual HZ incidence rates were calculated for 1993–2018. HZ risk was higher among unvaccinated children compared to vaccinated children across age groups; 64% higher before universal vaccination (RR: 0.36, 95% CI: 0.33, 0.39), and 32% higher after universal vaccination (RR: 0.68, 95% CI: 0.64, 0.73). Among unvaccinated children, HZ risk was 60% lower after vaccine programme implementation (RR: 0.40, 95% CI: 0.38, 0.43). Two-dose receipt corresponded with a 41% lower risk of HZ compared to one-dose receipt (RR: 0.59, 95% CI: 0.53, 0.65). Crude annual HZ incidence rates declined 64% after programme implementation, with decreases observed across age groups. Universal varicella vaccination programme implementation corresponds to decreased paediatric HZ incidence across age groups, in both vaccinated and unvaccinated individuals. Results from this study can be used to help inform varicella vaccination programme decision-making in other countries.

A systematic literature review of herpes zoster incidence worldwide

We conducted a systematic review to characterize the incidence rate of herpes zoster (HZ) in the general population, specifically in individuals ≥50 years of age. A total of 69 publications were included in the review. We found a cumulative incidence of HZ ranging from 2.9–19.5 cases per 1,000 population and an incidence rate of HZ ranging from 5.23–10.9 cases per 1,000 person-years. The cumulative incidence (3.22–11.2 versus 2.44–8.0 cases per 1,000 population) and incidence rates (6.05–12.8 versus 4.30–8.5 cases per 1,000 person-years) were higher in females than males. Studies revealed a trend of increasing incidence of HZ with increasing age and over time. Variations in incidence estimates can be attributed to the various study designs, case ascertainments, age distributions of the population and year of the study. HZ is associated with a substantial disease burden and is expected to increase due to population aging.

Incidence of Hospitalizations and Emergency Department Visits for Herpes Zoster in Immunocompromised and Immunocompetent Adults in Ontario, Canada, 2002-2016

BACKGROUND

Immunocompromised adults are at .increased risk of herpes zoster (HZ) infection and related complications. We aimed to assess the incidence of hospital-attended HZ (ie, seen in hospital or emergency department) in immunocompromised populations and compare it to immunocompetent populations.

METHODS

We calculated incidence rates (IRs) of hospital-attended HZ in Ontario, Canada, between 1 April 2002 and 31 August 2016 in adults ≥18 years of age categorized as immunocompromised or immunocompetent. We repeated these analyses by type of immunocompromising condition and provided incidence rate ratios (IRRs) comparing to immunocompetent adults. We also calculated IRs and IRRs of HZ complications by immunocompromised status.

RESULTS

There were 135 206 incident cases of hospital-attended HZ during the study period. Immunocompromised adults accounted for 13% of these cases despite representing 3% of the population. The risk of hospital-attended HZ was higher for immunocompromised adults compared with immunocompetent adults (IRR, 2.9 [95% confidence interval {CI}, 2.9-3.0]) and ranged across type of immunocompromising conditions, from 2.6 (95% CI, 2.6-2.7) in those with a solid tumor malignancy to 12.3 (95% CI, 11.3-13.2) in those who had undergone hematopoietic stem cell transplant. The risk of any HZ complication was higher in immunocompromised adults (IRR, 3.6 [95% CI, 3.5-3.7]) and highest for disseminated zoster (IRR, 32.8 [95% CI, 27.8-38.6]).

CONCLUSIONS

The risk of hospital-attended HZ and related complications was higher in immunocompromised populations compared with immunocompetent populations. Our findings underscore the high-risk nature of this population and the potential benefits that may be realized through HZ vaccination.

Incidence of varicella and herpes zoster after inclusion of varicella vaccine in national immunization schedule in Turkey: time trend study

The aim of the study was to investigate changes in the incidences of Varicella and Herpes Zoster (HZ) following introduction of single dose Varicella vaccine (VV) in Turkey. Changes in the incidences of varicella and HZ per 100,000 population were compared with pre (2011-2012) and post-VV period (2018-2019) throughout years between years 2011 and 2019 both for children and adults. In children ≤5 years of age, the annual incidences of varicella significantly decreased from 290 per 100000 children in 2011 to 24 per 100000 children in 2019 [p = .0001]. Also, for children ≤5 years the mean annual incidence of varicella decreased significantly [326/100000 ±51/100000 vs 23/100000 ± 1/100000; p = .014] between pre- and post-VV period. Moreover, the annual incidences of varicella significantly decreased from 43 per 100000 children in 2011 to 26 per 100000 children in 2019 in children age between 6 and 17 years. On the other hand, incidence of varicella in adult population (age >17 years) did not change significantly. Besides, the annual incidences of Herpes Zoster did not change significantly in children age stratas but significant increment observed in adult population. This increment was significant in adult age strata of 18-44 years, but non-significant in age strata of 45-64 years and >64 years. Thus, our study showed a significant reduction in the incidences of Varicella in children age stratas whereas significant increment in the incidence of HZ in adult population after the implementation of VV into the NIP of Turkey.

Incidence of varicella and herpes zoster after inclusion of varicella vaccine in national immunization schedule in Turkey: time trend study

The aim of the study was to investigate changes in the incidences of Varicella and Herpes Zoster (HZ) following introduction of single dose Varicella vaccine (VV) in Turkey. Changes in the incidences of varicella and HZ per 100,000 population were compared with pre (2011-2012) and post-VV period (2018-2019) throughout years between years 2011 and 2019 both for children and adults. In children ≤5 years of age, the annual incidences of varicella significantly decreased from 290 per 100000 children in 2011 to 24 per 100000 children in 2019 [p = .0001]. Also, for children ≤5 years the mean annual incidence of varicella decreased significantly [326/100000 ±51/100000 vs 23/100000 ± 1/100000; p = .014] between pre- and post-VV period. Moreover, the annual incidences of varicella significantly decreased from 43 per 100000 children in 2011 to 26 per 100000 children in 2019 in children age between 6 and 17 years. On the other hand, incidence of varicella in adult population (age >17 years) did not change significantly. Besides, the annual incidences of Herpes Zoster did not change significantly in children age stratas but significant increment observed in adult population. This increment was significant in adult age strata of 18-44 years, but non-significant in age strata of 45-64 years and >64 years. Thus, our study showed a significant reduction in the incidences of Varicella in children age stratas whereas significant increment in the incidence of HZ in adult population after the implementation of VV into the NIP of Turkey.

Herpes zoster in older adults in Ontario, 2002-2016: Investigating incidence and exploring equity

Older adults are at increased risk of herpes zoster (HZ) and post-herpetic neuralgia (PHN) and HZ vaccines are available to help prevent infection. The objective of our study was to provide updated data on incidence of HZ and PHN related to clinical and demographic factors in older adults to inform immunization practices. We conducted a population-based, retrospective cohort study and included all cases of HZ seen in outpatient, emergency department, and hospital settings for adults aged 65 years and over between April 1, 2002 to August 31, 2016 in Ontario, Canada. We calculated the incidence of HZ and PHN, and estimated the proportion within each subgroup that developed PHN. We also assessed incidence by neighbourhood-level income quintile before and after the availability of vaccine for private purchase. The average annual incidence of HZ in any setting was 59.0 per 10,000 older adults, with higher incidence in outpatient as opposed to hospital settings. Incidence was higher in the oldest age groups, females, and those classified as immunocompromised or frail. Relative to the pre-vaccine era, the disparities in incidence of HZ by neighbourhood-level income increased, with higher rates of HZ and PHN seen in those residing in lower income quintiles. Additional prevention efforts should be targeted toward adults who are immunocompromised, frail, and those living in lower socioeconomic quintiles. Future work should assess the impact of the zoster vaccine program with a particular focus on equity in the publicly-funded era.

The Impact of Varicella Vaccination on the Incidence of Varicella and Herpes Zoster in the United States: Updated Evidence From Observational Databases, 1991-2016

BACKGROUND

Universal childhood vaccination against varicella began in the United States as a 1-dose schedule in 1996, changing to a 2-dose schedule in 2006. The exogenous boosting hypothesis, which postulates that reexposure to circulating wild-type varicella delays the onset of herpes zoster, predicts a transient increase in the incidence of herpes zoster, peaking in adults 15-35 years after the start of varicella vaccination.

METHODS

This was a retrospective study of administrative claims data from the MarketScan Commercial and Medicare databases between 1991-2016. Outcome measures were the incidences of herpes zoster per 100 000 person-years, by calendar year and age category, and the annual rates of change in herpes zoster by age category, in an interrupted time series regression analysis, for the periods of 1991-1995 (prevaccine), 1996-2006 (1-dose vaccination period), and 2007-2016 (2-dose vaccination period).

RESULTS

The annual incidences of herpes zoster increased throughout the period of 1991-2012 in all adult age categories, with a plateau in 2013-2016 that was most evident in the ≥65 age group. In 1991-1995, the herpes zoster incidences increased at annual rates of 4-6% in age categories 18-34, 35-44, 45-54, and 55-64 years. In the same age categories during 1996-2006 and 2007-2016, the herpes zoster incidences increased at annual rates of 1-5%.

CONCLUSIONS

Although the annual incidence of herpes zoster in adults has continued to increase, the rates of change decreased during both the 1- and 2-dose vaccination periods. The hypothesized increase in herpes zoster predicted from modelling of the exogenous boosting hypothesis was not observed.

What We Know Now: An Economic Evaluation of Chickenpox Vaccination and Dose Timing Using an Agent-Based Model

OBJECTIVES

The value of chickenpox vaccination is still debated in the literature and by jurisdictions worldwide. This uncertainty is reflected in the inconsistent uptake of the vaccine, where some countries offer routine childhood immunization programs, others have targeted programs, and in many the vaccine is only privately available. Even across the countries that have universal funding for the vaccine, there is a diversity of schedules and dosing intervals. Using an agent-based model of chickenpox and shingles, we conducted an economic evaluation of chickenpox vaccination in Alberta, Canada.

METHODS

We compared the cost-effectiveness of 2 common chickenpox vaccination schedules, specifically a long dosing interval (first dose: 12 months; second dose: 4-6 years) and a short dosing interval (first dose: 12 months; second dose: 18 months).

RESULTS

The economic evaluation demonstrated a shorter dosing interval may be marginally preferred, although it consistently led to higher costs from both the societal and healthcare perspectives. We found that chickenpox vaccination would be cost-saving and highly cost-effective from the societal and healthcare perspective, assuming there was no impact on shingles.

CONCLUSION

Chickenpox vaccine was cost-effective when not considering shingles and remained so even if there was a minor increase in shingles following vaccination. However, if chickenpox vaccination did lead to a substantial increase in shingles, then chickenpox vaccination was not cost-effective from the healthcare perspective.

Effectiveness and cost-effectiveness of vaccination against herpes zoster in Canada: a modelling study

BACKGROUND

Two vaccines against herpes zoster are currently authorized for use in Canada: the recombinant subunit zoster vaccine and live attenuated zoster vaccine. We compared the effectiveness and cost-effectiveness of these 2 vaccines.

METHODS

We used a decision analytic static cohort model parametrized with Canadian epidemiologic and economic data. We performed the economic analysis from the health care system perspective, using a lifetime horizon and a 3% discount rate for costs and benefits. The primary outcome was the incremental cost per quality-adjusted life-year (QALY) gained, relative to no vaccination. We ran 30 000 simulations varying all model parameters, including vaccine costs, efficacy and waning.

RESULTS

The number needed to vaccinate (NNV) was higher for the live attenuated zoster vaccine than for the recombinant subunit zoster vaccine for all herpes zoster-related events at all ages. For example, in persons exactly 65 years old, for herpes zoster, median NNV was 21 (90% uncertainty interval [UI] 13-31) versus 8 (90% UI 6-18), and for postherpetic neuralgia, NNV was 64 (90% UI 33-93) versus 31 (90% UI 23-73). For the recombinant vaccine, the median cost-effectiveness ratios varied between cost-saving and $25 881 per QALY gained for adults aged 50 years or older. For the live vaccine, the cost-effectiveness ratios varied between cost-saving and $130 587 per QALY gained and were less than $45 000 per QALY gained only for those 65 to 75 years old. Given its higher efficacy, we estimated that the cost for the complete series of the recombinant vaccine could be $150 to $200 more than the cost of the live vaccine and still be considered cost-effective.

INTERPRETATION

Our model predicted that the recombinant subunit zoster vaccine is likely cost-effective in Canada for adults 60 years or older, and is likely more cost-effective than live attenuated zoster vaccine. These results have informed updated national and provincial recommendations on herpes zoster vaccination.

Vaccines for preventing herpes zoster in older adults

BACKGROUND

Herpes zoster, commonly known as shingles, is a neurocutaneous disease caused by the reactivation of the virus that causes varicella (chickenpox). After resolution of the varicella episode, the virus can remain latent in the sensitive dorsal ganglia of the spine. Years later, with declining immunity, the varicella zoster virus (VZV) can reactivate and cause herpes zoster, an extremely painful condition that can last many weeks or months and significantly compromise the quality of life of the affected person. The natural process of aging is associated with a reduction in cellular immunity, and this predisposes older people to herpes zoster. Vaccination with an attenuated form of the VZV activates specific T-cell production avoiding viral reactivation. The USA Food and Drug Administration has approved a herpes zoster vaccine with an attenuated active virus, live zoster vaccine (LZV), for clinical use amongst older adults, which has been tested in large populations. A new adjuvanted recombinant VZV subunit zoster vaccine, recombinant zoster vaccine (RZV), has also been approved. It consists of recombinant VZV glycoprotein E and a liposome-based AS01B adjuvant system. This is an update of a Cochrane Review last updated in 2016.

OBJECTIVES

To evaluate the effectiveness and safety of vaccination for preventing herpes zoster in older adults.

SEARCH METHODS

For this 2019 update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 1, January 2019), MEDLINE (1948 to January 2019), Embase (2010 to January 2019), CINAHL (1981 to January 2019), LILACS (1982 to January 2019), WHO ICTRP (on 31 January 2019) and ClinicalTrials.gov (on 31 January 2019).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) or quasi-RCTs comparing zoster vaccine (any dose and potency) versus any other type of intervention (e.g. varicella vaccine, antiviral medication), placebo, or no intervention (no vaccine). Outcomes were incidence of herpes zoster, adverse events (death, serious adverse events, systemic reactions, or local reaction occurring at any time after vaccination), and dropouts.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 11 new studies involving 18,615 participants in this update. The review now includes a total of 24 studies involving 88,531 participants. Only three studies assessed the incidence of herpes zoster in groups that received vaccines versus placebo. Most studies were conducted in high-income countries in Europe and North America and included healthy Caucasians (understood to be white participants) aged 60 years or over with no immunosuppressive comorbidities. Two studies were conducted in Japan. Fifteen studies used LZV. Nine studies tested an RZV. The overall quality of the evidence was moderate. Most data for the primary outcome (incidence of herpes zoster) and secondary outcomes (adverse events and dropouts) came from studies that had a low risk of bias and included a large number of participants. The incidence of herpes zoster at up to three years follow-up was lower in participants who received the LZV (one dose subcutaneously) than in those who received placebo (risk ratio (RR) 0.49, 95% confidence interval (CI) 0.43 to 0.56; risk difference (RD) 2%; number needed to treat for an additional beneficial outcome (NNTB) 50; moderate-quality evidence) in the largest study, which included 38,546 participants. There were no differences between the vaccinated and placebo groups for serious adverse events (RR 1.08, 95% CI 0.95 to 1.21) or deaths (RR 1.01, 95% CI 0.92 to 1.11; moderate-quality evidence). The vaccinated group had a higher incidence of one or more adverse events (RR 1.71, 95% CI 1.38 to 2.11; RD 23%; number needed to treat for an additional harmful outcome (NNTH) 4.3) and injection site adverse events (RR 3.73, 95% CI 1.93 to 7.21; RD 28%; NNTH 3.6) of mild to moderate intensity (moderate-quality evidence). These data came from four studies with 6980 participants aged 60 years or over. Two studies (29,311 participants for safety evaluation and 22,022 participants for efficacy evaluation) compared RZV (two doses intramuscularly, two months apart) versus placebo. Participants who received the new vaccine had a lower incidence of herpes zoster at 3.2 years follow-up (RR 0.08, 95% CI 0.03 to 0.23; RD 3%; NNTB 33; moderate-quality evidence). There were no differences between the vaccinated and placebo groups in incidence of serious adverse events (RR 0.97, 95% CI 0.91 to 1.03) or deaths (RR 0.94, 95% CI 0.84 to 1.04; moderate-quality evidence). The vaccinated group had a higher incidence of adverse events, any systemic symptom (RR 2.23, 95% CI 2.12 to 2.34; RD 33%; NNTH 3.0), and any local symptom (RR 6.89, 95% CI 6.37 to 7.45; RD 67%; NNTH 1.5). Although most participants reported that there symptoms were of mild to moderate intensity, the risk of dropouts (participants not returning for the second dose, two months after the first dose) was higher in the vaccine group than in the placebo group (RR 1.25, 95% CI 1.13 to 1.39; RD 1%; NNTH 100, moderate-quality evidence). Only one study reported funding from a non-commercial source (a university research foundation). All of the other included studies received funding from pharmaceutical companies. We did not conduct subgroup and sensitivity analyses AUTHORS' CONCLUSIONS: LZV and RZV are effective in preventing herpes zoster disease for up to three years (the main studies did not follow participants for more than three years). To date, there are no data to recommend revaccination after receiving the basic schedule for each type of vaccine. Both vaccines produce systemic and injection site adverse events of mild to moderate intensity.

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.

[Immunisation schedule of the Spanish Association of Paediatrics: 2019 recommendations]

The Advisory Committee on Vaccines of the Spanish Association of Paediatrics annually publishes the immunisation schedule considered optimal for children resident in Spain, according to available evidence on current vaccines. As regards funded immunisations, the 2+1 strategy (2, 4, 11 months) with hexavalent (DTPa-IPV-Hib-HB) and 13-valent pneumococcal vaccines are recommended. Administration of the 6-year booster dose with DTPa is recommended, with a poliomyelitis dose for children who had received the 2+1 scheme, as well as Tdap vaccine for adolescents and pregnant women in every pregnancy between 27 and 32 weeks gestation. The 2-dose scheme should be used for MMR (12 months and 3-4 years) and varicella (15 months and 3-4 years). MMRV vaccine could be applied as the second dose. Vaccination against HPV is recommended in both genders, preferably at 12 years of age. A stronger effort should be made to improve vaccination coverage. The new 9-valent vaccine is now available, expanding the coverage for both genders. Tetravalent meningococcal vaccine (MenACWY) is recommended at 12 months and 12-14 years, with a catch-up up at 19 years of age. It is also recommended in infants older than 6 weeks of age with risk factors, or travellers to countries with high incidence of ACWY meningococcal serogroups. As regards non-funded immunisations, it is recommended meningococcal B vaccination, with a 2+1 schedule, and requests that it be included in the National Immunisation Program. Vaccination against rotavirus is recommended in all infants.

Do varicella vaccination programs change the epidemiology of herpes zoster? A comprehensive review, with focus on the United States

Introduction: Policy-makers in many countries have been wary of introducing varicella vaccination programs because of concerns that reduced exposures to varicella-zoster virus could increase herpes zoster (HZ) incidence. The U.S. introduced varicella vaccination in 1996 and has empiric evidence regarding this concern. Areas covered: This comprehensive review provides background emphasizing the epidemiology of varicella and of HZ in the U.S. before and after the introduction of their respective vaccines. The epidemiology is complex, and interpretation is complicated by methodologic challenges, by unexplained increases in age-specific HZ incidence that preceded varicella vaccination, and by introduction of vaccines for prevention of HZ. Nonetheless, observations from studies using different platforms and designs have yielded consistent findings, suggesting they are robust. Expert opinion: There has been no evidence that the U.S. varicella vaccination program increased HZ incidence in the general adult population over baseline trends. Furthermore, HZ incidence in children is declining. The U.S. experience can inform the development of new generations of models to predict HZ trends. More importantly, it provides reassurance for countries considering varicella vaccination that an effective program can reduce varicella morbidity and mortality while reducing the likelihood of HZ among children, and potentially, over time, across the entire population.

Herpes zoster incidence in Germany - an indirect validation study for self-reported disease data from pretest studies of the population-based German National Cohort

BACKGROUND

Until now, herpes zoster (HZ)-related disease burden in Germany has been estimated based on health insurance data and clinical findings. However, the validity of self-reported HZ is unclear. This study investigated the validity of self-reported herpes zoster (HZ) and its complication postherpetic neuralgia (PHN) using data from the pretest studies of the German National Cohort (GNC) in comparison with estimates based on health insurance data.

METHODS

Data of 4751 participants aged between 20 and 69 years from two pretest studies of the GNC carried out in 2011 and 2012 were used. Based on self-reports of physician-diagnosed HZ and PHN, age- and sex-specific HZ incidence rates and PHN proportions were estimated. For comparison, estimates based on statutory health insurance data from the German population were considered.

RESULTS

Eleven percent (95%-CI, 10.4 to 12.3, n = 539) of the participants reported at least one HZ episode in their lifetime. Our estimated age-specific HZ incidence rates were lower than previous estimates based on statutory health insurance data. The PHN proportion in participants older than 50 years was 5.9% (1.9 to 13.9%), which was in line with estimates based on health insurance data.

CONCLUSION

As age- and sex-specific patterns were comparable with that in health insurance data, self-reported diagnosis of HZ seems to be a valid instrument for overall disease trends. Possible reasons for observed differences in incidence rates are recall bias in self-reported data or overestimation in health insurance data.

Understanding the role of exogenous boosting in modeling varicella vaccination

INTRODUCTION

The exogenous boosting (EB) hypothesis posits that cell-mediated immunity is boosted for individuals reexposed to varicella-zoster virus (VZV). Historically, mathematical models of the impact of universal childhood varicella vaccination (UVV) have used limited data to capture EB and often conclude that UVV will temporarily increase herpes zoster (HZ) incidence.

AREAS COVERED

We updated a 2013 systematic literature review of 40 studies to summarize new evidence from observational or modeling studies related to EB and its parameterization. We abstracted data on observational study designs and mathematical model structures, EB frameworks, and HZ-related parameter values.

EXPERT COMMENTARY

This review identified an additional 41 studies: 22 observational and 19 modeling studies. Observational analyses generally reported pre-UVV increases in HZ incidence, making it difficult to attribute post-UVV increases to UVV versus other causes. Modeling studies considered a range of EB frameworks, from no boosting to full permanent immunity. Mathematical modeling efforts are needed in countries with long-standing vaccination programs to capture the dynamics of VZV transmission and temporal changes that may affect HZ incidence. Use of real-world pre-/postvaccination data on varicella and HZ incidence to validate model predictions may improve approaches to EB parameterization and understanding of the effects of varicella vaccination programs.

Herpes Zoster Burden in Canadian Provinces: A Narrative Review and Comparison with Quebec Provincial Data

Background

The main aim of this review was to assess incidence rates and trends of medically attended and death cases of herpes zoster in Canada.

Methods

The search was conducted in five databases (PubMed, Cochrane, Embase, PsycNET, and Web of Science). Data on herpes zoster-related consultations and hospitalisations and deaths were also extracted from three Quebec provincial administrative databases (RAMQ, MED-ECHO, and ISQ).

Results

The electronic search yielded 587 publications. Seventeen publications satisfied inclusion criteria. These publications reported data from eleven studies. Ten studies used provincial databases, and one study used the Canadian Primary Care Sentinel Surveillance Network electronic database. Seven studies evaluated overall rates of medically attended cases (consultations and hospitalisations). Four of these studies reported an increase in rates of medically attended cases during the study period; one study reported stable rates, and two studies reported only an average rate. The rates varied from 316 to 450/100,000 p.y. The Quebec analysis shows similar rates with a slight decreasing trend (from 369 to 350/100,000 p.y.). Incidence rates of consultations were reported separately in three studies. Two studies reported an increase in rates (from 258 to 348/100,000 p.y. and from 324 to 366/100,000 p.y.), and the third study reported a decrease (from 525 to 479/100,000 p.y.). Hospitalization rates were reported separately in two studies, both reporting a decrease (from 12 to 8 cases/100,000 p.y. and from 9 to 4 cases/100,000 p.y.). Quebec data also showed a decrease, from 9 to 6 cases/100,000 p.y. One study reported herpes zoster-related deaths. In this study, the reported death rate was 0.7/1,000,000 p.y. in the overall population and 5.5/1,000,000 p.y. in those aged ≥65 years. Quebec analysis showed a death rate of 1.2/1,000,000 p.y. in the overall population and 8.6/1,000,000 p.y. in those aged ≥65 years.

Conclusions

The results of the reviewed studies and our analysis of Quebec provincial data indicate important variations in the reported overall incidence rates of medically attended herpes zoster cases in Canada. The trends in time are heterogeneous in studies in which hospitalisations and medical consultations were pooled together. We observed a decrease in hospitalization rates and a slight increase in consultation rates in studies reporting hospitalisations and consultations separately. These results consolidate the understanding of the herpes zoster burden in Canada and might be used as a tool in decision-making regarding future preventive interventions.

Summary of the NACI Update on Herpes Zoster Vaccines

BACKGROUND

Steep increases in herpes zoster (HZ) incidence, hospitalization due to HZ and the risk of post-herpetic neuralgia as a complication of HZ occur in people over 50 years of age. Two HZ vaccines are currently authorized for use in those 50 years of age and older in Canada: a live attenuated zoster vaccine (LZV) authorized in 2008; and a recombinant subunit vaccine (RZV) authorized in October 2017.

OBJECTIVES

To review current evidence and develop guidance on whether the previously authorized LZV (Zostavax®) and/or the recently authorized RZV (Shingrix®) vaccine should be offered to Canadians 50 years of age and older: 1) at a population-level, in publicly funded immunization programs; and 2) at an individual-level, to individuals wishing to prevent HZ, or by clinicians wishing to advise individual patients about preventing HZ.

METHODS

The National Advisory Committee on Immunization (NACI) Herpes Zoster Working Group developed a predefined search strategy to identify all eligible studies, assessed their quality, and summarized and analyzed the findings. A Cost Utility Analysis of LZV and RZV was also conducted from a health care system perspective. Recommendations were proposed according to NACI's evidence-based process. The strength of these recommendations was defined, and the Grade of evidence supporting them was identified. In light of the evidence, the recommendations were then considered and approved by NACI.

RESULTS

Five recommendations were developed for public health and individual-level decision-making. 1) RZV should be offered to populations/individuals >50 years of age without contraindications (Strong NACI Recommendation, Grade A evidence). 2) RZV should be offered to populations/individuals >50 years of age without contraindications who have previously been vaccinated with LZV (Strong NACI Recommendation, Grade A evidence). Re-immunization with two doses of RZV may be considered one year after LZV (Discretionary NACI Recommendation, Grade I evidence). 3) RZV should be offered to populations/individuals >50 years of age without contraindications who have had a previous episode of HZ (Strong NACI Recommendation, Grade B evidence). Immunization with two doses of RZV may be considered one year after the HZ episode (Discretionary NACI Recommendation, Grade I evidence). 4) LZV may be considered for immunocompetent populations/individuals >50 years of age without contraindications when RZV is contraindicated, unavailable or inaccessible (Discretionary NACI Recommendation, Grade A evidence). 5) RZV (not LZV) may be considered in immunocompromised adults >50 years of age on a case-by-case basis (Discretionary NACI Recommendation, Grade I evidence).

CONCLUSION

Both vaccines have been shown to be safe and immunogenic and to reduce the incidence of HZ and post-herpetic neuralgia. Vaccine efficacy of LZV against HZ decreases with age at, and time since vaccination. The vaccine efficacy of RZV remains higher and appears to decline more slowly than vaccine efficacy of LZV across all age groups. Both vaccines are cost-effective in those 50 years of age and older compared with no vaccination, especially in those 65-79 years of age. RZV is more cost-effective than LZV.

Evaluation of the effect of chickenpox vaccination on shingles epidemiology using agent-based modeling

BACKGROUND

Biological interactions between varicella (chickenpox) and herpes zoster (shingles), two diseases caused by the varicella zoster virus (VZV), continue to be debated including the potential effect on shingles cases following the introduction of universal childhood chickenpox vaccination programs. We investigated how chickenpox vaccination in Alberta impacts the incidence and age-distribution of shingles over 75 years post-vaccination, taking into consideration a variety of plausible theories of waning and boosting of immunity.

METHODS

We developed an agent-based model representing VZV disease, transmission, vaccination states and coverage, waning and boosting of immunity in a stylized geographic area, utilizing a distance-based network. We derived parameters from literature, including modeling, epidemiological, and immunology studies. We calibrated our model to the age-specific incidence of shingles and chickenpox prior to vaccination to derive optimal combinations of duration of boosting (DoB) and waning of immunity. We conducted paired simulations with and without implementing chickenpox vaccination. We computed the count and cumulative incidence rate of shingles cases at 10, 25, 50, and 75 years intervals, following introduction of vaccination, and compared the difference between runs with vaccination and without vaccination using the Mann-Whitney U-test to determine statistical significance. We carried out sensitivity analyses by increasing and lowering vaccination coverage and removing biological effect of boosting.

RESULTS

Chickenpox vaccination led to a decrease in chickenpox cases. The cumulative incidence of chickenpox had dropped from 1,254 cases per 100,000 person-years pre chickenpox vaccination to 193 cases per 100,000 person-years 10 years after the vaccine implementation. We observed an increase in the all-ages shingles cumulative incidence at 10 and 25 years post chickenpox vaccination and mixed cumulative incidence change at 50 and 75 years post-vaccination. The magnitude of change was sensitive to DoB and ranged from an increase of 22-100 per 100,000 person-years at 10 years post-vaccination for two and seven years of boosting respectively (p < 0.001). At 75 years post-vaccination, cumulative incidence ranged from a decline of 70 to an increase of 71 per 100,000 person-years for two and seven years of boosting respectively (p < 0.001). Sensitivity analyses had a minimal impact on our inferences except for removing the effect of boosting.

DISCUSSION

Our model demonstrates that over the longer time period, there will be a reduction in shingles incidence driven by the depletion of the source of shingles reactivation; however in the short to medium term some age cohorts may experience an increase in shingles incidence. Our model offers a platform to further explore the relationship between chickenpox and shingles, including analyzing the impact of different chickenpox vaccination schedules and cost-effectiveness studies.

Incidence rate of breakthrough varicella observed in healthy children after 1 or 2 doses of varicella vaccine: Results from a meta-analysis

BACKGROUND

Although extensive varicella vaccination coverage has been reported in many countries, breakthrough varicella (BV) still occurs in healthy children. We performed a meta-analysis to understand whether 2 varicella vaccine doses are needed in children and, if so, to determine the best time to vaccinate.

METHODS

The BV incidence rates after 1 or 2 doses of varicella vaccine were pooled using random effects, and 95% confidence intervals (CI) were used to estimate the risk factors after vaccination.

RESULTS

A total of 27 original articles were included in this meta-analysis. The pooled average BV incidence rate in children vaccinated with 1 dose was 8.5 cases per 1,000 person years (PY) (95% confidence interval [CI], 5.3-13.7; random effects model) and 2.2 cases per 1,000 PY (95% CI, 0.5-9.3; random effects model) in children vaccinated with 2 doses. The pooled trend of the annual BV incidence rate from the first to eighth year fluctuated, with a peak annual incidence rate of 35.3 cases per 1,000 population in the fourth year. The meta-regression showed that design type, type of vaccine, and their interaction accounted for approximately 71.74% of the heterogeneity in the average BV incidence rate after 1 vaccine dose.

CONCLUSIONS

Two doses of varicella vaccine are more effective than a single dose, and 3-4 years between the first and second vaccinations may achieve higher efficacy.

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.

Varicella vaccination - the global experience

INTRODUCTION

Varicella, although a frequently benign childhood disease, nevertheless represents a considerable health burden. WHO recommends including varicella vaccines in universal routine vaccination programs, and maintaining coverage >80%. Many countries have successfully introduced varicella vaccination and have benefited from lower disease burden, but many others have not adopted the vaccine. Reasons include cost commitment for a 'mild childhood disease' or concerns that vaccination will shift varicella to older age groups or increase herpes zoster incidence. Areas covered: This literature review summarizes the effectiveness and epidemiological impact of varicella immunization programs. Expert commentary: Varicella vaccines are immunogenic with acceptable safety profiles. One and two dose schedules are highly effective against varicella and large reductions in disease incidence, particularly moderate-severe disease, have been widely reported. There is currently no evidence to suggest that the introduction of varicella vaccination results in a shift of varicella disease burden to older age groups. Although epidemiological studies have shown an increased incidence of herpes zoster since the vaccines were launched, there are many other contributing factors, and indeed, this secular trend was evident before their introduction. In conclusion, varicella vaccination easily fits into existing immunization programs and significantly reduces the often underestimated burden of varicella.

The temporal impact of aging on the burden of herpes zoster

Background

The risk of Herpes Zoster (HZ) increases with age and various studies have also demonstrated an increasing HZ incidence globally. Simultaneously, the global trend of an aging population has placed a greater burden on the healthcare system. This study aims to estimate the potential burden of HZ over time accounting for the increasing trends of both HZ incidence and global aging.

Methods

A recent systematic review on HZ incidence identified studies that evaluated the temporal effects of HZ incidence. Data from the identified studies were extracted to estimate the trend of HZ incidence in the ≥65-year-old age cohort. The incidence rates were estimated up to the year 2030 using two scenarios: a linear extrapolation and a last observation carried forward. Three countries were chosen to perform the analysis on: Australia, Japan and the United States.

Results

The incidence data from the three countries showed an average annual increase between 2.35 and 3.74% over the time period of the studies selected. The elderly population for the US, Japan and Australia are expected to increase by 55, 10 and 53% respectively by the year 2030 compared to the levels in 2015. Under the first scenario between 2001 and 2030, the number of annual incident cases of HZ in those aged ≥65 years is expected to increase by +343% (293,785 to 1,303,328), +176% (158,616 to 437,867) and +376% (18,105 to 86,268) in the US, Japan and Australia respectively while those for the second scenario are +150%, +83% and +223% respectively. In the US alone, the estimated annual cost of HZ-related cases in the ≥65 age cohort is approximately 4.74 Billion US$ in 2030.

Conclusions

The increasing incidence of HZ coupled with the demographic trends (i.e., aging population and greater life expectancy) in many countries are likely to imply a rising economic burden of HZ on already constrained healthcare budgets.