Herpes zoster vaccination in people aged 50-59 years.

Herpes zoster (or shingles), an infectious disease caused by reactivation of latent varicella-zoster virus (VZV) in the dorsal root or cranial nerve ganglia, typically manifests as unilateral acute pain accompanied by a vesicular rash. The acute pain and rash usually resolve within 2– 4 weeks without treatment. Postherpetic neuralgia, commonly defined as pain that lasts .3 months after the onset of rash or cutaneous healing, is the most common and feared complication and can persist occasionally for years in some patients. In addition to postherpetic neuralgia, some patients may suffer from ocular, hearing, or other serious neurological complications [1, 2]. Age-related decline in cell-mediated immune responses is a major risk factor of herpes zoster as well as postherpetic neuralgia. The annualized incidence of herpes zoster was 4.6, 6.9, 9.5, and 10.9 per 1000 people aged 50–59, 60–69, 70–79, and $80 years, respectively [3]; the corresponding proportion of patients who had postherpetic neuralgia in each age group was approximately 5%, 10%, 17%, and 20%, respectively [4]. People with immunosuppressive illness or those receiving immunosuppressive therapy are more vulnerable to herpes zoster and more likely to develop postherpetic neuralgia. The annualized incidence of herpes zoster was 29.4 per 1000 men seropositive for human immunodeficiency virus (HIV) and 2.0 per 1000 HIV-seronegative men [5]. Diabetes mellitus, often accompanied by altered cell-mediated immunity, was associated with an increased risk of herpes zoster and prescriptions of opioids within a year of diagnosis of shingles [6]. Antiviral therapy can accelerate cutaneous healing and reduce severity and duration of pain. The treatment should be initiated in 72 hours after acute-symptom onset to maximize benefit [7], but such rapid treatment is often impractical due to delays in seeing a doctor or reaching a diagnosis. The treatment for postherpetic neuralgia is complex; sometimes treatment efficacy is unsatisfactory. Over half of patients require .1 prescription drug for relieving postherpetic neuralgia, but the pain can be relieved only in 50% of patients despite treatment [8]. These issues highlight a need to develop a vaccine that prevents herpes zoster and postherpetic neuralgia. In 2005, efficacy of a herpes zoster vaccine, Zostavax, was demonstrated among people aged $60 [9]. In 2006, the US Food and Drug Administration (FDA) approved Zostavax to prevent shingles in individuals aged $60 [10]. In 2008, the US Centers for Disease Control and Prevention (CDC) recommended routine vaccination among people aged $60 [11]. In the present issue of Clinical Infectious Diseases, Schmader et al [12] report the efficacy and safety profile of Zostavax in people aged 50–59. The event-driven trial was conducted among healthy subjects without immune compromise. The primary efficacy outcome was the relative reduction in the incidence of herpes zoster in the Zostavax versus placebo group. The secondary efficacy endpoint was the mean severity-by-duration score, a composite measure of herpes zoster incidence, severity, and duration of acute pain. Zostavax’s efficacy for postherpetic neuralgia was not evaluated in this study. The primary safety and tolerability endpoint was the incidence of serious adverse events. The study subjects were enrolled from people who reported a history of varicella or resided in a VZV endemic area for $30 years. The study defined ‘‘endemic area’’ as an area where varicella was a common childhood disease. In the United States, VZV infection in people aged .50 was .99% [13]; therefore, the restriction of ‘‘endemic area’’ may be less essential and the study findings might be generalized to other areas in study regions. Received 21 November 2011; accepted 22 November 2011; electronically published 30 January 2012. Correspondence: Jian-meng Liu, PhD, Institute of Reproductive and Child Health/Ministry of Health Key Laboratory of Reproductive Health, Peking University Health Science Center, 38 College Rd, Haidian district, Beijing 100191, China ([email protected]). Clinical Infectious Diseases 2012;54(7):929–30 The Author 2012. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@ oup.com. DOI: 10.1093/cid/cir974