Serostatus following live attenuated vaccination administered before pediatric liver transplantation.

After liver transplantation (LT), live attenuated vaccines (LAVs) are generally contraindicated. LAVs are recommended before LT for patients ≥ 6 months of age. However, the evidence supporting this practice is limited. Patients were enrolled before and after LT. Clinical data for patients were obtained from medical records. Serum antibody titers were evaluated at the time of enrollment and prospectively. Serum antibody titers were measured with a hemagglutination inhibition test for measles and rubella and with an enzyme-linked immunosorbent assay for varicella and mumps. Univariate and multivariate analyses were performed to investigate the factors that affect the serostatus. Serological analyses of 49 patients immunized before LT (median age, 45 months; male, 35%) were performed. Underlying diseases were biliary atresia (n = 27; 55%), metabolic diseases (n = 13; 27%), fulminant hepatic failure (n = 5; 10%), and others (n = 4; 8%). The seropositivity rate after each vaccine was 46.9% (measles), 89.4% (rubella), 67.5% (varicella), and 48.8% (mumps). Factors independently associated with seronegativity were a vaccination age < 12 months for measles (P = .002), a lower body weight for varicella (P = 0.01), and underlying diseases other than biliary atresia for mumps (P = .004). No serious adverse event was observed during the study period. The immunogenicity of LAVs before LT was high for rubella but low for the others. Before LT, further vaccination strategies are needed for patients. In addition, serological follow-up may be indicated for patients with factors associated with seronegativity.