In years past, astute clinicians observed that adults who acquired herpes zoster almost invariably denied having had varicella (chickenpox) during childhood. A link between the two diseases was therefore postulated, and both were assumed to be viral diseases. In 1953, Weller1 isolated virus particles from varicella and zoster vesicular lesions and confirmed the identity of the varicella-zoster (HZ) virus. It is assumed that adults who develop herpes zoster are hypoimmune and not totally unsusceptible to HZ virus.
Varicella of childhood is usually, but not always a mild, highly contagious disease. The same cannot be said for adults in whom the disease usually is severe and is frequently complicated by varicella pneumonia. Cimons et al2 report such a case in which truly heroic measures were needed to ensure survival.
An exception to the rule of mildness in childhood varicella is found in a report by Hook et al.3
Hussey HH. Varicella-Zoster Infections: Zoster Immune Globulin. JAMA. 1974;228(7):876. doi:10.1001/jama.1974.03230320046035