Herpes Zoster and Postherpetic Neuralgia: a review of the effects of vaccination

Herpes zoster (HZ) results from reactivation of varicella zoster virus which has been persistent but clinically latent in dorsal root and cranial nerve ganglia since primary infection, usually as a child, with varicella (chicken pox). HZ affects 20–30% of individuals during their lifetime and up to 50% of those ≥80 years old. Although serious life- or sight-threatening complications occur rarely, postherpetic neuralgia (PHN) is the most common complication. Both HZ and PHN are most common in the elderly. Declining cell-mediated immunity resulting from immune senescence appears to be the cause. Incidence of HZ is also high in individuals who are immunocom-promised as a result of disease or its treatment. HZ also occurs in younger and fit individuals but is usually mild and complications are rare.