Vaccination against Herpes Zoster and Postherpetic Neuralgia.

BACKGROUND Herpes zoster (HZ) and postherpetic neuralgia (PHN) cause significant morbidity in older adults. The incidence and severity of HZ and PHN increase with age in association with an age-related decline in varicella-zoster virus (VZV)-specific cell-mediated immunity (VZV-CMI). VZV vaccines can boost VZV-CMI. Therefore, we tested the hypothesis that VZV vaccination would protect older adults against HZ and PHN. METHODS We enrolled 38,546 adults > or =60 years of age in a randomized, double-blind, placebo-controlled trial of an investigational HZ vaccine and actively followed subjects for the development of HZ. The primary end point was the burden of illness due to HZ (HZ BOI), a composite measure of the incidence, severity, and duration of pain and discomfort caused by HZ. The secondary end point was the incidence of PHN. RESULTS Subject retention was >95%. HZ vaccine reduced the HZ BOI by 61.1% (95% confidence interval [CI], 51.1%-69.1%; P<.001) and reduced the incidence of PHN by 66.5% (95% CI, 47.5%-79.2%; P<.001). The incidence of HZ was also reduced by 51.3% (95% CI, 44.2%-57.6%; P<.001). HZ vaccine was well tolerated; injection site reactions were generally mild. HZ vaccine neither caused nor induced HZ. CONCLUSION The Shingles Prevention Study demonstrated that HZ vaccine significantly reduced the morbidity due to HZ and PHN in older adults.