Grant: Operating Grant

Influenza is an immensely important public health problem as underscored by the recent pandemic. A key difference between pandemics of the past is the ever-increasing population of immunocompromised people. This is important because this population may serve as highly contagious nodes of spread (i.e. 'super-spreaders') thereby hampering public health efforts. Among the most immunosuppressed are organ transplant recipients and current vaccine strategies lead to sub-optimal effectiveness in these patients. Therefore, it is essential to develop more effective and novel ways to immunize them. Intradermal vaccination takes advantage of local immune cells and may therefore be more effective than standard intramuscular vaccine. In order to test this, we enrolled 240 organ transplant patients and randomized them to receive either the standard intramuscular vaccine or novel high-dose intradermal vaccine. We have saved all the necessary blood samples needed for testing. Our primary outcome will be a protective antibody response to the vaccine. We will also examine cellular immune responses in these patients. In addition, all patients will have testing for antibodies directed against the transplanted organ to determine whether immunization can contribute to organ rejection. Importance of the Study: This will be a unique study and the largest ever randomized trial of influenza vaccination in this patient population. The results will have immediate clinical relevance and may lead to important improvements in patient care.