Advances in the understanding of the pathogenesis and epidemiology of herpes zoster

Abstract

SUMMARY The primary varicella zoster virus (VZV) infection results in chickenpox (varicella), which is transmitted via the airborne route. VZV is highly infectious, but in the USA the incidence of varicella has been reduced by 76–87% as a result of the varicella vaccine. The virus establishes latency in the dorsal root ganglia during varicella and, when reactivated, travels along the sensory nerve axons to cause shingles (herpes zoster [HZ]). There are over 1 million cases of HZ in the USA each year, with an estimated lifetime attack rate of 30%. The incidence of HZ, which causes significant morbidity, increases with age and reaches approximately 10 cases per 1,000 patient-years by age 80. Cell-mediated immunity (CMI) is known to decline with age as part of immunosenescence, and decreased CMI is associated with reactivation of VZV. This article provides an overview of our emerging understanding of the epidemiology and pathogenesis of varicella and HZ, in addition to exploring the current theories on latency and reactivation. Understanding the risk factors for developing HZ and the complications associated with infection, particularly in older people, is important for prompt diagnosis and management of HZ in primary care, and they are therefore also reviewed.

The role of vaccination in successful independent ageing

“…Primary infection with varicella zoster virus (VZV) causes varicella and then the virus remains latent in the sensory ganglia [21]. HZ is due to reactivation of the latent VZV and, although the exact mechanism of reactivation is not well known, declining immunity with age (immunosenescence) has been reported to be the main risk factor [21].…”

“…HZ is due to reactivation of the latent VZV and, although the exact mechanism of reactivation is not well known, declining immunity with age (immunosenescence) has been reported to be the main risk factor [21]. The complications of HZ can be neurological, ophthalmic, dermatological and visceral, but the most important, both in terms of incidence and severity is postherpetic neuralgia (PHN) [21]. HZ occurs more frequently in older individuals, with about 2/3rd of cases in those aged 50 years and about 2/3rd of PHN in those aged 70 years [18,19,[22][23][24][25].…”

Herpes Zoster Duplex Bilateralis in an Immunocompetent Adolescent Girl at Koshi Zonal Hospital, Morang

“…It is characterized by grouped vesicles, distributed 3 unilaterally, usually over one or two adjacent dermatomes. Usually, the ini al manifesta on of zoster is pain that is sharply localized to skin area supplied by one or more dermatomes.…”

Prevention of Herpes Zoster and its complications: From clinical evidence to real life experience

“…VZV primary infection (varicella) elicits a long lasting antibody-mediated and cell-mediated immune response; VZV-specific antibodies (Abs) play a relevant role on the healing of varicella but are not able to avoid viral latency. 48 Live attenuated zoster vaccine (Oka/ Merck strain) with its high antigen content is able to boost VZVspecific CMI preventing reactivation of latent VZV, VZV replication and subsequent neurological damages. It cannot have an impact on an already ongoing HZ and/or PHN.…”