Review of the Persistence of Herpes Zoster Vaccine Efficacy in Clinical Trials

Purpose: The live attenuated herpes zoster vaccine' was approved for the prevention of shingles in 2006. Initial Phase III clinical trials proved vaccine efficacy persisted during the study duration; however, assessment of long-term efficacy required additional studies. This article reviews efficacy data for the zoster vaccine that have been published since 2004. It focuses on studies assessing declining vaccine efficacy. Methods: MEDLINE, EMBASE, CENTRAL, and CINAHL databases were searched for zoster vaccine efficacy trials. Randomized controlled trials published from 2004 to 2015 were included in the review. Findings: Six studies were included in the review. The zoster vaccine reduced the risk of herpes zoster by 51.3% to 72.4% in 2 Phase III trials. Primary and other analyses showed the vaccine was effective at reducing the burden of illness (61.1%), postherpetic neuralgia (66.5%), disease interference on functional status (66.2%), and disease impact on health-related quality of life (55%) compared with placebo. Surveillance studies showed a decrease in vaccine efficacy for reducing the incidence of herpes zoster during follow-up years 3.3 to 7.8 (39.6% relative reduction) and 4.7 to 11.6 (21.1% relative reduction). (C) 2015 Elsevier HS Journals, Inc. All rights reserved.