How Little We Know Herpes Zoster

Herpes Zoster: Risk Factors for Occurrence, Complications, and Recurrence with a Focus on Immunocompromised Patients

BACKGROUND

The varicella-zoster virus is a highly contagious human herpesvirus that primarily causes varicella (chickenpox) as an initial infection, targeting T cells, neurons, as well as skin cells, and can later reactivate to cause herpes zoster (shingles). Following reactivation, the varicella-zoster virus infection can lead to severe complications, the most common of which is postherpetic neuralgia. Risk factors include aging, immunosuppression, chronic diseases such as diabetes, cardiovascular disorders, respiratory conditions, and others.

OBJECTIVE

In this article, we present an analysis of factors increasing the risk of herpes zoster occurrence, complications, and recurrences (in particular in immunocompromised patients).

A systematic literature review of the epidemiology and burden of herpes zoster in selected locales in Asia Pacific

Herpes zoster (HZ) is a painful rash which typically affects older adults. This is of concern in Asia-Pacific given its aging population. As HZ epidemiology and burden are evolving, this systematic literature review aimed to update the current understanding of HZ burden and associated costs for selected Asia-Pacific locales. MEDLINE and Embase were searched for English articles of HZ studies conducted in Australia, China, Hong Kong, Japan, Korea, New Zealand, Singapore, and Taiwan. Eligible outcomes included HZ incidence and prevalence, occurrence of HZ-related complications, healthcare resource utilization, costs, and HZ-associated quality of life outcomes. This paper focused on HZ data in the general adult population (N = 90 articles). Substantial HZ-related disease and economic burden were observed in these locales, consistent with global trends. These findings reinforce the increasing burden of HZ and need for preventive strategies, which may include raising awareness and encouraging timely vaccination.

Herpes Zoster Recurrence: A Narrative Review of the Literature

INTRODUCTION

Herpes zoster (HZ; shingles) is a painful, cutaneous disease caused by reactivation of the varicella zoster virus, which causes varicella (chickenpox) typically during childhood. The considerable healthcare burden of HZ is relatively well documented, with approximately one in three individuals experiencing at least one episode during their lifetime, debilitating symptoms including neuropathic pain, and complications such as post-herpetic neuralgia, vision loss, and rarely, stroke, and increased severity in immunocompromised individuals. However, we are not aware of a comprehensive review of literature specifically examining the burden of HZ recurrence.

METHODS

We conducted a PubMed search (1 January 2003-2 February 2023) to assess available literature on the incidence, risk factors, and clinical features of HZ recurrence.

RESULTS

The incidence of HZ recurrence reported by the studies identified was wide ranging. Studies in general populations of immunocompetent or immunocompetent/immunosuppressed (mixed) populations with an initial HZ episode estimate that approximately 1.2-9.6% of individuals may experience HZ recurrence, with an incidence rate of 1.7-16.6 cases per 1000 person-years. HZ recurrence was reported in 0.0-18.2% of immunocompromised individuals with HZ, with an incidence rate of 17.0-55 cases per 1000 person-years. Incidence rates varied according to study design, follow-up, and study populations. Recognized risk factors for HZ recurrence include immunocompromised status, female sex, family history, and comorbidities such as diabetes. Other factors that may predispose individuals to recurrence include long-lasting pain after the initial HZ episode and the presence of herpes zoster ophthalmicus.

DISCUSSION

Our review underlines that following an initial HZ episode, individuals remain at risk of HZ recurrence, adding to the disease burden in a population. As HZ is preventable by vaccination, national HZ vaccination recommendations should include the need for and timing of vaccination in both immunocompetent and immunocompromised individuals who have a history of HZ.

Low Trend for VZV-Associated Disease Patients to Visit Neurologists

Background

Herpes zoster (HZ) is a skin disease that can also cause virus-infectious peripheral neuropathies. Despite this, there is limited information on patient preferences for seeking medical attention for HZ and zoster-associated pain (ZAP). Our study aimed to evaluate how frequently patients with ZAP choose to visit neurologists for their symptoms.

Methods

This study conducted a retrospective review of electronic health records in three general hospitals from January 2017 to June 2022. Using association rule mining, the study analyzed referral behaviors.

Results

We identified 33,633 patients with 111,488 outpatient visits over 5.5 years. The study found that the majority of patients (74.77-91.22%) visited dermatologists during their first outpatient visit, while only a small percentage (0.86-1.47%) preferred to consult a neurologist. The proportion of patients referred to a specialist during their medical visit varied significantly between different specialties within the same hospital (p <0.05) and even within the same specialty (p<0.05). There was a weak association (Lift:1.00-1.17) of referral behaviors between dermatology and neurology. Across the three hospitals, the average number of visits to a neurologist for ZAP was 1.42-2.49, with an average electronic health record duration of 11-15 days per patient. After consulting with a neurologist, some patients were referred to other specialists.

Conclusion

It was observed that patients with HZ and ZAP tended to visit a variety of specialists, with only a small number seeking the assistance of neurologists. However, from the perspective of neuroprotection, it is the duty of neurologists to provide more means.

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.

Humoral Immunity to Varicella Zoster Virus in Patients with Systemic Lupus Erythematosus and Rheumatoid Arthritis Compared to Healthy Controls

Background: The prevalence of herpes zoster (HZ) is high in patients with rheumatic diseases. Systemic lupus erythematosus (SLE) doubles the risk for developing HZ. However, little is known about natural humoral immunity against varicella zoster virus (VZV) in patients with SLE. Hence, we compared VZV IgG antibody concentrations in a group of SLE patients with healthy controls and patients with rheumatoid arthritis (RA). Methods: n = 56 patients with SLE, n = 54 patients with RA, and n = 56 healthy controls were included in this study. The VZV IgG antibody concentration was measured using an enzyme-linked immunosorbent assay (ELISA). The antibody concentrations were compared between the groups. Results: Overall IgG antibody titers for VZV in SLE patients were comparable to healthy controls but higher when compared to patients with rheumatoid arthritis (p = 0.0012). In consequence, antibody levels in controls were higher than in RA patients (p = 0.0097). Stratification by age revealed highest titers among SLE patients in the fourth life decade (p = 0.03 for controls, p = 0.0008 for RA patients) whereas RA patients in their sixth decade had the lowest antibody concentration (p = 0.03 for controls, p = 0.04 for SLE patients). Regarding the individual HZ history, antibody levels of SLE patients with a positive history exceeded all other groups. Conclusions: Although humoral VZV immunity in SLE patients is comparable to healthy controls it seems to be pronounced in young SLE patients between 30 and 39. The lowest VZV IgG levels were found in RA patients. HZ seems to induce antibody production, particularly in patients with SLE. Immunological processes might contribute to VZV antibody levels in SLE patients, but further investigations are needed to substantiate this hypothesis. Even though the increased HZ prevalence seems to be independent of humoral immunity in SLE patients, reduced humoral immunity might contribute to HZ in RA patients. The available HZ subunit vaccination might be an appropriate way to reduce the HZ risk in patients with rheumatic diseases.