Early post-transplant vaccination with pandemic influenza A/H1N1 vaccine in pediatric heart transplant recipients.

Pandemic influenza A/H1N1 virus has the potential to cause severe disease in pediatric transplant patients. A pandemic vaccine against H1N1 is effective in immunocompetent children. We investigated the immunogenicity of this vaccine when given in the first six months after heart transplantation. Four patients younger than two yr received two doses of vaccine and one patient older than seven yr received one dose. Titers were obtained using the HAI at baseline and after final immunization. Five patients were enrolled, ages 0.5-7 yr. Median age at the time of transplant was five months (range 3 wk-7 yr). All patients received induction with anti-thymoglobulin and maintenance immunosuppression with tacrolimus, MMF, and prednisone. Patients were immunized with the adjuvanted H1N1 vaccine after heart transplant at median time of nine wk (range 5-23 wk) post-transplant. Three of five developed protective titers against H1N1. A proportion of pediatric patients may respond to influenza vaccine even when immunized in the early post-transplant period.