THE FREQUENCY AND CONSEQUENCES OF VARICELLA EXPOSURE AND VARICELLA INFECTION IN CHILDREN RECEIVING MAINTENANCE THERAPY FOR ACUTE LYMPHOBLASTIC-LEUKEMIA

Purpose: The frequency and cost of varicella and varicella exposure we re determined in children receiving maintenance chemotherapy for acute lymphocytic leukemia, and the cost of a preventative strategy using t he varicella vaccine was estimated. Patients and Methods: Retrospectiv e analysis of clinic and hospital records for 472 children at 12 sites who were receiving maintenance chemotherapy on Protocol 105 of the Ch ildrens Cancer Group. Results: During a mean maintenance period of 21/ 2 years there were 120 exposures to varicella among susceptible childr en (10/100 patient-years). During the same period there were 60 cases of varicella (4.6/100 patient-years). Half of the cases of varicella o ccurred without a known exposure. Exposures and varicella resulted in significant omission or delay in chemotherapy. Total medical charges f or varicella-related events were $492,000 ($470 per varicella exposure ; $7,450 per case of varicella). A proposed preventative strategy usin g varicella vaccine after 6 months of maintenance therapy would theore tically reduce varicella-related charges by 80%. Conclusions: Varicell a exposure and varicella are common in this patient population. The us e of varicella vaccine during the early maintenance period should be c onsidered to prevent these events. This strategy is likely to be safe, and will save significant medical charges, drug omission, disease-rel ated morbidity, hospitalization, and work and school disruption.