Response to varicella immunization in pediatric liver transplant recipients

Background. Individuals undergoing therapeutic immunosuppression are at risk of severe varicella-zoster virus (VZV) infection, particularly those without evidence of previous infection. Methods. Eleven children, median age 10 months (range 5.5 months to 7 years and 9 months) received one dose of varicella vaccine (Varilrix, SmithKline Beecham plc, UK) before liver transplantation (median interval 95 days, range 40-289 days). The serological response to varicella vaccine was evaluated retrospectively and matched with the outcome and management of any subsequent exposures to VZV. Results. Three children responded postimmunization, six children showed no response, and in two children the outcome was difficult to interpret having received blood products. Four children required varicella-zoster immunoglobulin prophylaxis posttransplantation, two of whom developed mild chickenpox. Conclusions. Only 3 of 11 children developed a clear antibody response to varicella vaccine. Administration of varicella vaccine did not affect the management of subsequent VZV exposures.