Response to diphtheria and tetanus booster vaccination in pediatric renal transplant recipients

Background. Although inactivated vaccines are recommended for immunocompromized patients, efficacy and safety of diphtheria and tetanus immunization in renal transplant recipients have received little attention so far. The aim of the study was to investigate the response to a standard diphtheria and tetanus booster vaccination in pediatric renal transplant recipients. Methods. Forty-two children, median age 13.2 years (range, 7.8-18.9 years) with complete primary immunization 9.2 years (0.9-15.4 years) before transplantation were enrolled. Immunosuppression consisted of cyclosporine plus prednisolone in 15 (36%), cyclosporine, azathioprine, and prednisolone in 24 (57%), and tacrolimus plus prednisolone in 3 (7%). Antibodies were measured by enzyme-linked immunosorbent assay before and 1, 6, and 12 months after vaccination. Results. Before vaccination, protective antibody concentrations exceeding 0.1 IU/ml against diphtheria were found in 16 children (38%). Thirty-eight (90%) had protective antibody concentrations against tetanus. After booster immunization, the protection rate against diphtheria rose to 95% at 1 month with a decline to 93% at 6 and 76% at 12 months. Protection against tetanus was complete after vaccination and persisted over the observation. Antibody concentrations were comparable to those reported for healthy children. Statistical analysis showed no influence of allograft function, immunosuppressive regimen, previous cytotoxic therapy, or time between primary immunization and end-stage renal failure on antibody response. Immunization was well tolerated and kidney function remained unaffected in patients with stable allograft function. Conclusions. Diphtheria and tetanus vaccination can be performed effectively and safely in renal transplant recipients as generally recommended.