TOWARD THE ELIMINATION OF VARICELLA IN CHILDREN WITH LEUKEMIA

Varicella may produce significant illness in children with leukemia. To reduce morbidity, Varicella Vaccine (VV) was given as soon as possible following diagnosis of leukemia. Twenty-eight of 29 given VV no earlier than 1 year post diagnosis seroconverted; 1 developed mild varicella at 1 year and another at 2 years post immunization. In addition, 5 of 28 lost antibody. Only 10 of 17 children immunized earlier than 1 year post diagnosis had satisfactory responses to VV. Passive immunization was started at the time of diagnosis of leukemia to provide protection prior to the time active immunization could be successfully accomplished. VZIG produced low levels of antibody that was detectable <10-12 weeks. Patients who received transfusion of platelets, but not packed red blood cells, were found to have much higher antibody levels. Protection of children with leukemia can be achieved by giving VV one year post diagnosis. Prior to this time passive immunization, probably best accomplished with an intravenous product, could reduce morbidity from varicella in these high risk children.