Presented by: Michael McKendrick. Royal Hallamshire Hospital, Sheffield, UK.

Shingles occurs as the result of reactivation of the varicella zoster virus which is dormant in the posterior root ganglion. Reactivation becomes more common with advancing years to the extent that it occurs at about 10/1000 per year in patients over 80 years. The lifetime chance of developing shingles is about 25%. A person of 85 years has a 50% chance of having had shingles. The main complication, post herpetic neuralgia (PHN) can be severe, persistent and life-altering, and is more common in the elderly. Despite benefits from antiviral therapy and analgesia, PHN still occurs.

Reactivation of VZV in immunocompetent individuals is consequent on the decline in immunity, particularly cell-mediated immunity, with advancing years and the reduced chance of exposure to the chickenpox virus, which is probably important in boosting immunity. Chickenpox vaccine using a high dose of Oka strain has been shown to boost cell-mediated immunity. A placebo-controlled study of the vaccine in 38 500 persons over 60 years demonstrated efficacy with a 61.1% reduction in burden of illness, 66.5% reduction of PHN and 51.3% reduction of the incidence of shingles.

Shingles in the elderly is likely to increase with predicted increasing numbers of individuals >65 years in western countries and reduced boosting from chickenpox in countries where vaccine is used. Health-economic analysis of shingles vaccine has limitations related to uncertainty about the duration of protection after vaccination and the cost of vaccine. However, modelling has suggested it is likely to be a beneficial health intervention.