Early results of a trial of the Oka-strain varicella vaccine in children with leukaemia or other malignancies in Sweden.

Nineteen children with acute lymphoblastic leukaemia or other malignancies, aged 3-13 years, with negative histories of varicella-zoster virus (VZV) and of whom 5 were still on regular maintenance chemotherapy, were vaccinated with the Oka-strain varicella vaccine. Mild systemic reactions, involving low-grade fever of a few days duration, were recorded in 4 of the vaccinees. Two of them also developed an extremely sparse rash. A mild local reaction at the vaccination site was observed in 1 child. Conversion rates for circulating VZV antibody, measured at 4-6 weeks and 4-6 months after vaccination using an indirect immunofluorescence test, were 8/12 (67%) and 5/9 (56%), respectively. Markedly lower antibody conversion rates of 5/18 (28%) and 5/14 (36%) were found by means of the enzyme-linked immunosorbent assay method. Corresponding conversion rates for cell-mediated immunity against VZV, determined using a specific lymphocyte stimulation technique, were 9/17 (52%) and 12/14 (86%), respectively.