Induction of Immunity Against Measles in Pediatric Liver Transplant Recipients

Inclusion Criteria: * Age ≥ 12 months * Measles-specific IgG antibodies negative (\<0.2 IU/L), as detected by the routine ELISA assay * ≥ 12 months from the time of transplantation and ≥ 2 months from the time of an acute rejection episode * Steroids \< 2 mg/kg/day, tacrolimus \< 0.3mg/kg/day and tacrolimus level \< 8 ng/ml for \> 1 month. * Total lymphocyte count ≥ 750 cells/ul at time of immunization Exclusion Criteria: * Known wild-type measles exposure during the last four weeks * Measles-containing immunoglobulins administered within the 5 months preceding the measles vaccine. If the child receives measles-containing Ig before an additional dose of MMR vaccine, he/she will be withdrawn from the study * Antiviral agents administered during the last four weeks * Febrile illness (\>38.5°) in the 72 hours before vaccine administration * Chronic aspirin therapy * Any other immunization with a live-attenuated vaccine during the last four weeks * Pregnancy