Lack of serologic immunity against vaccine-preventable diseases in children after thoracic transplantation

We investigated whether children after heart- (HTx) or heart-lung transplantation (HLTx) show protective antibody levels against recommended vaccinations, whether vaccination schedules are completed and which factors influence serologic immunity. We performed a cross sectional ELISA - quantification of specific antibodies in 46 patients after pediatric thoracic Tx. Findings were correlated to vaccination history, age at Tx, clinical course and immunosuppressive regimen. We found protective antibody levels against diphtheria in 74% of patients, against tetanus in 22%, against Haemophilus influenzae type b in 30% and against Streptococcus pneumoniae in 59%. Antibody concentrations against live attenuated vaccines were significantly lower in children transplanted in the first 2 years of life. Antibodies were absent for measles in 55% of late - and 81% of early transplanted children, for mumps in 66%/94%, for rubella in 30%/56% and for Varicella in 34%/63%. We found significant correlation of low antibody concentrations and age at Tx. Patients without protective antibody concentrations had significantly longer use of steroids. Vaccination schedules were incomplete or delayed in the majority of patients associated with more days in hospital pre-Tx. Our study shows that closer adherence to pretransplantation vaccination schedules and also post-transplantation monitoring of antibody levels are required in transplant patients.