The controversy of varicella vaccination in children with acute lymphoblastic leukemia

Background: The available guidelines for varicella vaccination of susceptible children with acute lymphoblastic leukemia (ALL) have become increasingly conservative. However, vaccination of those who have remained in continuous complete remission for 1 year and are receiving chemotherapy is still considered a reasonable option. There is little available data to allow a comparison of the risk versus benefit of vaccinating these patients. Procedure: We retrospectively reviewed mortality due to varicella in the records of 15 pediatric ALL study groups throughout Europe, Asia, and North America during the period 1984-2008. Results: We found that 20 of 35,128 children with ALL (0.057%; 95% confidence interval [CI], 0.037-0.088%) died of VZV infection. The mortality rate was lower in North America (3 of 11,558 children, 0.026%; 95% CI, 0.009-0.076%) than in the Asian countries (2 of 4,882 children, 0.041%; 95% CI, 0.011-0.149%) and in Europe (15 of 18,688 children, 0.080%; 95% CI, 0.049-0.132%) consistent with the generally higher rate of VZV vaccination in North America. Fourteen of the 20 patients (70%) died during the first year of treatment for ALL. One death was attributed to varicella vaccination. Conclusions: The negligible rate of fatal varicella infection in children with ALL, the risk that accompanies vaccination, and the necessity of withholding chemotherapy for vaccination appear to outweigh the potential benefit of varicella vaccination for children during treatment of ALL.