Herpes zoster causes substantial morbidity, especially among older adults. Although the acute cutaneous manifestations can be painful and troublesome, the most important consequence of herpes zoster (shingles) is the chronic pain syndrome known as postherpetic neuralgia (PHN). Previous studies have suggested that declining varicella-zoster virus (VZV)-specific cell-mediated immune (CMI) responses account for the increased frequency of herpes zoster seen in older adults. This led to the idea that immunization designed to boost VZV-specific CMI responses might reduce the risk of herpes zoster. This hypothesis was tested in a large, randomized, placebo-controlled clinical trial called the Shingles Prevention Study (SPS). Compared with the placebo group, herpes zoster vaccine recipients had a 61.1% reduction in zoster "burden of illness" (an index incorporating incidence and severity of herpes zoster); a 66.5% reduction in the incidence of postherpetic neuralgia; and a 51.3% reduction in the incidence of herpes zoster. The incidence of serious adverse events was not different between the overall vaccine and placebo populations. The most frequently encountered adverse event among vaccine recipients was local reactogenicity, with self-limited and generally mild tenderness, warmth, or erythema occurring at the injection site in about one-half of vaccine recipients. The zoster vaccine was approved by the US Food and Drug Administration in 2006 and is indicated for prevention of herpes zoster in immunocompetent persons aged 60 years and older.
Perspective: The herpes zoster vaccine provides physicians with an effective means for reducing a patient's risk for developing shingles and its attendant complications. No significant safety concerns regarding the vaccine have been identified. Indications for use of the attenuated-virus vaccine in special subpopulations continue to evolve.