Efficacy of zoster immunoglobulin in prophylaxis of varicella in high-risk patients.

During a period of 2 1/2 years 190 children have been prophylactically treated with zoster immunoglobulin in norway. Information on 130 (68%) of these children was obtained. This group included patients suffering from leukemia, lymphoma, and other malignant disorders, and patients with autoimmune diseases, with impaired immune mechanisms or with for other reasons increased frequency of infections, as well as premature and weak newborns, and infants born to mothers who developed varicella during the last 4 days before delivery. Of the patients who received zoster immunoglobulin within 3 days after exposure, 2.9% developed weak symptoms of varicella. When zoster immunoglobulin was administered 4-5 days after exposure, 37.5% contracted varicella, and when given more than 5 days after exposure, 50% developed the disease. The 9 neonates with possible intrauterine exposure are not included in these figures.