Effective immunization against influenza in pediatric renal transplant recipients

Viral infections such as influenza are an important cause of morbidity following organ transplantation. We evaluated the immunogenicity of a commercially available influenza vaccine in pediatric renal transplant recipients in a two-phase, prospective study. In phase one, 47 transplant patients and seven control subjects with bronchopulmonary dysplasia received influenza vaccine. Sera were collected at the time of vaccination and 6 wk later. In phase two, sera from 18 transplant recipients and 47 healthy adults who had received the same vaccine were collected 6-12 months after vaccination. Antibody titers to the A/Taiwan/1/86 antigen were measured with hemagglutination inhibition assay in both phases of the study. Vaccine was well tolerated in all subjects. No vaccinated patient required hospitalization for complications of influenza infection. Vaccination did not increase the frequency of acute allograft rejection. In phase one, 43 patients (91%) and 5 controls (71%) either seroconverted (developed a fourfold or greater rise in titer), or developed post-vaccination titers > or = 1:160 (p = NS). Among the transplant recipients, non-seroconverters had a higher pre-vaccination geometric mean antibody titer (GMT) than those who seroconverted. Seroconversion developed independently of whether patients received double or triple immunosuppression. In phase two, post-vaccination GMT were similar for patients and control subjects at 11.5 and 8 months post-vaccination, respectively. In our study, influenza vaccination produced equivalent humoral immunity in transplant recipients and normal subjects. Routine influenza vaccination should be performed annually in this high-risk population.