Bate J, et al. - Experts pursued an exploration of the likely rate of patient randomisation and intended to facilitate sample size calculation for a full-scale phase III trial of varicella zoster immunoglobulin (VZIG) and aciclovir as postexposure prophylaxis against chickenpox in children with cancer. The enrollment consisted of children under 16 years of age with a diagnosis of cancer: Currently or within 6 months of receiving cancer treatment and with negative varicella zoster virus (VZV) serostatus at diagnosis or within the last 3 months. Factors that could be used to modify the design of a definitive trial were determined. A total of 32 patients were registered and 3 patients were randomised following VZV exposure. Findings revealed that all 3 subjects were randomised to receive aciclovir and there were no cases of breakthrough varicella.