Dr Hope-Simpson presents a study of all cases of herpes zoster occurring in his general practice during a sixteen-year period. The rate was 3·4 per thousand per annum, rising with age, and the distribution of lesions reflected that of the varicella rash.
It was found that severity increased with age, but that the condition did not occur in epidemics, and that there was no characteristic seasonal variation. A low prevalence of varicella was usually associated with a high incidence of zoster.
Dr Hope-Simpson suggests that herpes zoster is a spontaneous manifestation of varicella infection. Following the primary infection (chickenpox), virus becomes latent in the sensory ganglia, where it can be reactivated from time to time (herpes zoster). Herpes zoster then represents an adaptation enabling varicella virus to survive for long periods, even without a continuous supply of persons susceptible to chickenpox.