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 transplan t recipients in a two-phase, prospective study. In phase one, 47 trans plant patients and seven control subjects with bronchopulmonary dyspla sia received influenza vaccine. Sera were collected at the time of vac cination and 6 wk later. In phase two, sera from 18 transplant recipie nts and 47 healthy adults who had received the same vaccine were colle cted 6-12 months after vaccination. Antibody titers to the A/Taiwan/1/ 86 antigen were measured with a hemagglutination inhibition assay in b oth phases of the study. Vaccine was well tolerated in all subjects. N o vaccinated patient required hospitalization for complications of inf luenza infection. Vaccination did not increase the frequency of acute allograft rejection. In phase one, 43 patients (91%) and 5 controls (7 1%) either seroconverted (developed a fourfold or greater rise in tite r), or developed post-vaccination titers greater than or equal to 1:16 0 (p=NS). Among the transplant recipients, non-seroconverters had a hi gher pre-vaccination geometric mean antibody titer (GMT) than those wh o seroconverted. Seroconversion developed independently of whether pat ients 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 recipie nts and normal subjects. Routine influenza vaccination should be perfo rmed annually in this high-risk population.