Efficacy of live zoster vaccine in preventing zoster and postherpetic neuralgia.

Declining cell-mediated immunity to varicella zoster virus (VZV) in elderly individuals results in virus reactivation manifest by zoster (shingles) and postherpetic neuralgia (PHN). To prevent virus reactivation, a new VZV vaccine (Zostavax; Merck) that boosts cell-mediated immunity to VZV was developed. The 3-year Shingles Prevention Study showed that Zostavax significantly reduced burden of disease because of zoster and PHN. Despite its cost-effectiveness for adults aged 65-75 years, as determined in the United States, Canada and UK, <2% of immunocompetent adults over age 60 years in the United States were immunized in 2007. This was because of a combination of lack of patient awareness of the vaccine, physicians' uncertainty about the duration of protection and different cost-sharing plans for immunization. Nevertheless, zoster vaccine is safe, effective and highly recommended for immunization of immunocompetent individuals over age 60 years with no history of recent zoster.