RESUMO
BACKGROUND: Solid organ transplant recipients undergoing immunosuppressive therapy are considered to be at high risk of serious infectious complications. In 2009, a new influenza pandemic caused serious infections and deaths, especially among children and immunocompromised patients. Herein we have reported the safety and efficacy of a single-shot monovalent whole-virus vaccine against H1N1 infection in the pediatric renal transplant population. METHODS: In November and December 2009, we vaccinated 37 renal transplant children and adolescents and measured their antibody responses. Seroprotection, seroconversion, and seroconversion factors were analyzed at 21 days after vaccination. RESULTS: None of the vaccinated patients experienced vaccine-related side effects. None of the patients had an H1N1 influenza infection after vaccination. All of the patients showed elevations in antibody titer at 21 days after vaccination. In contrast, only 29.72% of the patients achieved a safe seroprotection level and only 18.75% a safe seroconversion rate. More intense immunosuppressive treatment displayed negative effect on seroprotection and seroconversion, and antibody production significantly increased with age. No other factor was observed to influence seroprotection. CONCLUSIONS: We recommend vaccination of children and adolescent renal transplant recipients against H1N1 virus. However, a single shot of vaccine may not be sufficient; to achieve seroprotection, a booster vaccination and measurement of the antibody response are needed to assure protection of our patients.