Antiviral treatment for preventing postherpetic neuralgia

Mitochondrial Haplogroups as a Risk Factor for Herpes Zoster

Background.  Herpes zoster, or shingles, is a common, painful reactivation of latent varicella zoster virus infection. Understanding host factors that predispose to herpes zoster may permit development of more effective prevention strategies. Our objective was to examine mitochondrial haplogroups as a potential host factor related to herpes zoster incidence. Methods.  Study participants were drawn from BioVU, a deoxyribonucleic acid (DNA) biobank connected to deidentified electronic medical records (EMRs) from Vanderbilt University Medical Center. Our study used 9691 Caucasian individuals with herpes zoster status determined by International Classification of Diseases, Ninth Revision codes 053-053.9. Cases and controls were matched on sex and date of birth within 5 years. Mitochondrial haplogroups were defined from mitochondrial DNA variants genotyped on the Illumina 660W or Illumina Infinium Human-Exome Beadchip. Sex and date of birth were extracted from the EMR. Results.  European mitochondrial haplogroup H had a protective association with herpes zoster status (odds ratio [OR] = .82; 95% confidence interval [CI], .71-.94; P = .005), whereas haplogroup clade IWX was a risk factor for herpes zoster status (OR = 1.38; 95% CI, 1.07-1.77; P = .01). Conclusions.  Mitochondrial haplogroup influences herpes zoster risk. Knowledge of a patient's mitochondrial haplogroup could allow for a precision approach to the management of herpes zoster risk through vaccination strategies and management of other modifiable risk factors.

A Prospective Study of Herpes Zoster in Children

Background:

Herpes zoster (HZ) is a dermatomal viral infection, caused by reactivation of varicella zoster virus (VZV) that persists in the posterior root ganglion. HZ is uncommonly reported in immunocompetent children. It may be due to intrauterine VZV infection or secondary to postnatal exposure to VZV at an early age.

Aims:

Our study was to review clinico-epidemiological data for HZ in children for early diagnosis and treatment to prevent complications.

Materials and Methods:

A prospective observational study was conducted from January 2013 to December 2014. Consecutive cases clinically diagnosed as HZ in the pediatric age group were taken up.

Results:

We report the clinico-epidemiological study of 26 cases of HZ, their benign course and recovery among children.

Conclusions:

HZ is a rare disease in childhood. Varicella in early childhood is a risk factor of HZ in immunocompromised and immunocompetent children. Childhood zoster occurs in either healthy or underlying immunodeficient children. The appearance of HZ in a young child does not always imply an underlying immunodeficiency or malignancy. But the identification of HZ with or without immunodeficiency is of prime importance from the treatment and prognostic point of view and should be considered in the differential diagnosis of vesicular eruptions. The prognosis is generally good in healthy children.

The herpes zoster subunit vaccine

INTRODUCTION

Herpes zoster (HZ) causes severe pain and rash in older people and may be complicated by prolonged pain (postherpetic neuralgia; PHN).

AREAS COVERED

HZ results from reactivation of latent varicella-zoster virus (VZV) infection, often associated with age related or other causes of decreased T cell immunity. A concentrated live attenuated vaccine boosts this immunity and provides partial protection against HZ, but this decreases with age and declines over 5-8 years. The new HZ subunit (HZ/su or Shingrix) vaccine combines a key surface VZV glycoprotein (E) with T cell boosting adjuvant (AS01B). It is highly efficacious in protection (97%) against HZ in immunocompetent subjects, with no decline in advancing age and protection maintained for >3 years. Phase I-II trials showed safety and similar immunogenicity in severely immunocompromised patients. Local injection site pain and swelling can be severe in a minority (9.5%) but is transient (2 days).

EXPERT OPINION

The HZ/su vaccine appears very promising in immunocompetent patients in the ZoE-50 controlled trial. The unblinding of the current ZoE-50 trial and publication of results from the accompanying ZoE-70 trial will reveal more about its mechanism of action and its efficacy against PHN, particularly in subjects >70 years. Phase III trial results in immunocompromised patients are eagerly awaited.

Quantification of risk factors for postherpetic neuralgia in herpes zoster patients: A cohort study

OBJECTIVE

To investigate risk factors for postherpetic neuralgia, the neuropathic pain that commonly follows herpes zoster.

METHODS

Using primary care data from the Clinical Practice Research Datalink, we fitted multivariable logistic regression models to investigate potential risk factors for postherpetic neuralgia (defined as pain ≥90 days after zoster, based on diagnostic or prescription codes), including demographic characteristics, comorbidities, and characteristics of the acute zoster episode. We also assessed whether the effects were modified by antiviral use.

RESULTS

Of 119,413 zoster patients, 6,956 (5.8%) developed postherpetic neuralgia. Postherpetic neuralgia risk rose steeply with age, most sharply between 50 and 79 years (adjusted odds ratio [OR] for a 10-year increase, 1.70, 99% confidence interval 1.63-1.78). Postherpetic neuralgia risk was higher in women (6.3% vs 5.1% in men: OR 1.19, 1.10-1.27) and those with severely immunosuppressive conditions, including leukemia (13.7%: 2.07, 1.08-3.96) and lymphoma (12.7%: 2.45, 1.53-3.92); autoimmune conditions, including rheumatoid arthritis (9.1%: 1.20, 0.99-1.46); and other comorbidities, including asthma and diabetes. Current and ex-smokers, as well as underweight and obese individuals, were at increased risk of postherpetic neuralgia. Antiviral use was not associated with postherpetic neuralgia (OR 1.04, 0.97-1.11). However, the increased risk associated with severe immunosuppression appeared less pronounced in patients given antivirals.

CONCLUSIONS

Postherpetic neuralgia risk was increased for a number of patient characteristics and comorbidities, notably with age and among those with severe immunosuppression. As zoster vaccination is contraindicated for patients with severe immunosuppression, strategies to prevent zoster in these patients, which could include the new subunit zoster vaccine, are an increasing priority.

The use of Zostavax in Spain: the economic case for vaccination of individuals aged 50 years and older

Background Population aging brings up a number of health issues, one of which is an increased incidence of herpes zoster (HZ) and its complication, post-herpetic neuralgia (PHN). Zostavax vaccine has recently become available to prevent HZ and PHN. This study evaluates the cost-effectiveness of vaccination against HZ in Spain considering a vaccination of the population aged 50 years and older and comparing this to the current situation where no vaccination is being administered. Methods An existing, validated, and published economic model was adapted to Spain using relevant local input parameters and costs from 2013. Results Vaccinating 30% of the Spanish population aged 50 years and older resulted in €16,577/QALY gained, €2025/HZ case avoided, and €5594/PHN case avoided under the third-party payer perspective. From a societal perspective, the ICERs increased by 6%, due to the higher price of the vaccine. The number needed to vaccinate to prevent one case was 20 for HZ, and 63 for PHN3. Sensitivity analyses showed that the model was most sensitive to the HZ and PHN epidemiological data, the health state utilities values, and vaccine price used. Conclusion Considering an acceptable range of cost-effectiveness of €30,000-€50,000 per QALY gained, vaccination of the 50+ population in Spain against HZ with a new vaccine, Zostavax, is cost-effective and makes good use of the valuable healthcare budget.

Cost-effectiveness analysis of a vaccination program for the prevention of herpes zoster and post-herpetic neuralgia in adults aged 50 and over in Germany

Herpes zoster (HZ; shingles) is a common viral disease that affects the nerves and surrounding skin causing a painful dermatomal rash and leading to debilitating complications such as, mainly, post-herpetic neuralgia (PHN). Currently, there is no effective treatment for HZ and PHN. The objective of this study was to assess the cost-effectiveness of a HZ vaccination program in Germany. An existing Markov Model was adapted to the German healthcare setting to compare a vaccination policy to no vaccination on a lifetime time-horizon, considering 2 scenarios: vaccinating people starting at the age of 50 or at the age of 60 years, from the perspective of the statutory health insurance (SHI) and the societal perspective. According to the perspective, vaccinating 20% of the 60+ German population resulted in 162,713 to 186,732 HZ and 31,657 to 35,793 PHN cases avoided. Corresponding incremental cost-effectiveness ratios (ICER) were 39,306 €/QALY from the SHI perspective and 37,417 €/QALY from a societal perspective. Results for the 50+ German population ranged from 336,468 to 394,575 HZ and from 48,637 to 56,087 PHN cases avoided from the societal perspective. Corresponding ICER were 39,782 €/QALY from a SHI perspective and 32,848 €/QALY from a societal perspective. Sensitivity analyses showed that results are mainly impacted by discount rates, utility values and use of alternative epidemiological data.The model indicated that a HZ vaccination policy in Germany leads to significant public health benefits and could be a cost-effective intervention. The results were robust and consistent with local and international existing literature.

Cost-Effectiveness of Herpes Zoster Vaccine for Persons Aged 50 Years

BACKGROUND

Each year, herpes zoster (HZ) affects 1 million U.S. adults, many of whom develop postherpetic neuralgia (PHN). Zoster vaccine is licensed for persons aged 50 years or older, but its cost-effectiveness for those aged 50 to 59 years is unknown.

OBJECTIVE

To estimate the cost-effectiveness of HZ vaccine versus no vaccination.

DESIGN

Markov model.

DATA SOURCES

Medical literature.

TARGET POPULATION

Adults aged 50 years.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTION

HZ vaccine.

OUTCOME MEASURES

Number of HZ and PHN cases prevented and incremental cost per quality-adjusted life-year (QALY) saved.

RESULTS OF BASE-CASE ANALYSIS

For every 1000 persons receiving the vaccine at age 50 years, 25 HZ cases and 1 PHN case could be prevented. The incremental cost-effectiveness ratio (ICER) for HZ vaccine versus no vaccine was $323 456 per QALY.

RESULTS OF SENSITIVITY ANALYSIS

In deterministic and scenario sensitivity analyses, the only variables that produced an ICER less than $100 000 per QALY were vaccine cost (at a value of $80) and the rate at which efficacy wanes. In probabilistic sensitivity analysis, the mean ICER was $500 754 per QALY (95% CI, $93 510 to $1 691 211 per QALY). At a willingness-to-pay threshold of $100 000 per QALY, the probability that vaccination would be cost-effective was 3%.

LIMITATION

Long-term effectiveness data for HZ vaccine are lacking for 50-year-old adults.

CONCLUSION

Herpes zoster vaccine for persons aged 50 years does not seem to represent good value according to generally accepted standards. Our findings support the decision of the Advisory Committee on Immunization Practices not to recommend the vaccine for adults in this age group.

PRIMARY FUNDING SOURCE

None.

Varicella zoster virus infection

Infection with varicella zoster virus (VZV) causes varicella (chickenpox), which can be severe in immunocompromised individuals, infants and adults. Primary infection is followed by latency in ganglionic neurons. During this period, no virus particles are produced and no obvious neuronal damage occurs. Reactivation of the virus leads to virus replication, which causes zoster (shingles) in tissues innervated by the involved neurons, inflammation and cell death - a process that can lead to persistent radicular pain (postherpetic neuralgia). The pathogenesis of postherpetic neuralgia is unknown and it is difficult to treat. Furthermore, other zoster complications can develop, including myelitis, cranial nerve palsies, meningitis, stroke (vasculopathy), retinitis, and gastroenterological infections such as ulcers, pancreatitis and hepatitis. VZV is the only human herpesvirus for which highly effective vaccines are available. After varicella or vaccination, both wild-type and vaccine-type VZV establish latency, and long-term immunity to varicella develops. However, immunity does not protect against reactivation. Thus, two vaccines are used: one to prevent varicella and one to prevent zoster. In this Primer we discuss the pathogenesis, diagnosis, treatment, and prevention of VZV infections, with an emphasis on the molecular events that regulate these diseases. For an illustrated summary of this Primer, visit: http://go.nature.com/14xVI1.

Herpes zoster epidemiology, management, and disease and economic burden in Europe: a multidisciplinary perspective

Herpes zoster (HZ) is primarily a disease of nerve tissue but the acute and longer-term manifestations require multidisciplinary knowledge and involvement in their management. Complications may be dermatological (e.g. secondary bacterial infection), neurological (e.g. long-term pain, segmental paresis, stroke), ophthalmological (e.g. keratitis, iridocyclitis, secondary glaucoma) or visceral (e.g. pneumonia, hepatitis). The age-related increased incidence of HZ and its complications is thought to be a result of the decline in cell-mediated immunity (immunosenescence), higher incidence of comorbidities with age and social-environmental changes. Individuals who are immunocompromised as a result of disease or therapy are also at increased risk, independent of age. HZ and its complications (particularly postherpetic neuralgia) create a significant burden for the patient, carers, healthcare systems and employers. Prevention and treatment of HZ complications remain a therapeutic challenge despite recent advances. This is an overview of the multidisciplinary implications and management of HZ in which the potential contribution of vaccination to reducing the incidence HZ and its complications are also discussed.

Reducing the burden of Herpes Zoster in Italy

Herpes Zoster (HZ) is a viral disease with painful neuro-dermatologic manifestations. Incidence increases with age. In Italy, the estimated incidence is 6.3 cases/1000 person/year; hospital admissions are less than 2%, 69% in patients aged over 65 years. The most frequent complication of HZ is Post-Herpetic Neuralgia (PHN) characterized by metameric pain, allodynia, and hyperalgesia. In Italy 20.6% and 9.2% of HZ patients experience PHN after 3 and 6 months, respectively. Available antiviral and analgesic treatments are relatively unsatisfactory in reducing pain and length of the disease. Prevention has recently become possible with the live attenuated vaccine Oka/Merck. Clinical studies show a reduction of 51% in the incidence of the disease, 61% of its burden and 67% of PHN in vaccinees. Protection seems to be long lasting and vaccine safety matches registration requirements. Available evidence suggests that the costs for QALY (less than € 20 000) and avoided cases is favorable. Due to the heavy burden of disease, it is time to offer this vaccination to elderly population.

Diagnóstico e manejo do herpes-zóster pelo médico de família e comunidade

O herpesvírus que causa a varicela (catapora) persiste de forma latente no sistema nervoso, podendo se reativar e propagar através das raízes nervosas e se manifestar de forma tardia através de lesões cutâneas dolorosas, condição essa denominada herpes-zóster. O diagnóstico é primariamente clínico, devendo ser feito diagnóstico diferencial com impetigo, dermatite de contato, dermatite herpetiforme e, também, com o próprio herpes simples. Uma vez confirmado o diagnóstico, o tratamento deve ser instituído nas primeiras 72 horas após a erupção das lesões e tem como base a terapia antiviral. Dentre os antivirais, o valaciclovir e o fanciclovir têm eficácia superior quando comparados ao aciclovir. A complicação mais frequente do herpes-zóster é a neuralgia pós-herpética, usualmente manejada com antidepressivos tricíclicos, anticonvulsivantes, lidocaína tópica ou capsaicina. Recentemente foi introduzida no Brasil uma vacina de vírus atenuado para o herpes-zóster, composta pelo mesmo vírus da vacina contra varicela, porém em concentração maior. Entretanto, essa vacina ainda apresenta custo elevado e não está disponível no Sistema Único de Saúde.