We found that pediatricians have enhanced specific cellular immunity to varicella-zoster virus (VZV) compared with the general population, which may be due to reexposure to VZV from children with chickenpox. There have been some reported that the varicella vaccine enhance the specific cellular immunity. To estimate the efficacy of varicella vaccine for protection against herpes zoster in the elderly, we investigated the incidence of herpes zoster in 500 pediatricians and family practitioners with their fifties and sixties, and history of reexposure to VZV in 61 patients with herpes zoster by questionnaires retrospectively. Thirty-four of 352 pediatricians had a past history of herpes zoster. The incidence per 100,000 person-years of herpes zoster was 65.2 in those in their fifties and 158.2 in those in their sixties, which are 1/2 to 1/8 of other reports regarding the general population. Among 61 immunocompetent patients with herpes zoster, only 4 patients (6.6%) had the chance for reexpose to VZV before their herpes zoster. Only 7 (17.5%) of the 40 patients older than 50 years of age lived with their children less than 14 years of age. Twenty-three (57.5%) of them lived without their children and grandchildren. They are thought to be less chance to reexpose to VZV through children. We may think that the booster effect by reexposure to VZV plays an important role to prevent herpes zoster. Therefore, we can speculate that the varicella vaccine may protect against herpes zoster in the elderly by the enhanced specific cellular immunity due to the booster effect.