Abstract
After the establishment of initial infection of chickenpox, varicella-zoster virus (VZV) latently infects the sensory nerve ganglia of the host, and is reactivated by immunocompromised status, aging, and stress, resulting in herpes zoster. VZV-specific cell-mediated immunity is thought to be important for controlling the onset of herpes zoster, but many questions have yet to be fully answered. How much of an immune reduction induce herpes zoster? Is humoral immunity involved in prevention? A large scale epidemiological study was recently carried out to clarify the relationship between herpes zoster and immunological condition in a population of middle-aged and elderly residents (50 years and older) of Shodoshima Island, Japan. The level of VZV-specific cell-mediated immunity assessed by VZV skin test was inversely correlated with the onset of herpes zoster, herpes zoster severity, and the onset of postherpetic neuralgia. On the other hand, no association was observed between VZV-specific humoral immunity (antibodies) and herpes zoster. These findings strongly suggest that the existing chickenpox vaccine, which enhances VZV-specific cell-mediated immunity, may be useful for the prevention of herpes zoster.
