Influenza Vaccination in Solid Organ Tranplant Recipients

Abstract

Immunogenicity of intramuscular influenza vaccine is suboptimal in organ transplant recipients although intradermal vaccine may be superior by targeting dermal dendritic cells to stimulate a response. 229 patients were randomized to IM or high-dose ID vaccine during the 2010-11 season. Pre- and 1 month post-vaccine bloodwork measured serology by hemagglutination inhibition assay (for influenza A/H1N1, A/H3N2 and B strains) and HLA antibody. Seroconversion was defined as a 4-fold rise in titer. Median time from transplant was 4.9 years. In 212 evaluable patients (105 IM, 107 ID), seroconversion to at least one antigen was 46.7% & 51.4% respectively (p=0.5). Seroconversion to at least 1 antigen was greater if i) ≥ 6 months post-transplant (53.2% vs. 19.2%; p=0.001) or ii) on <2g of mycophenolate mofetil (60.0% vs. 36.7%; p=0.001). Our study suggests that intradermal vaccine is safe, may be more immunogenic in selected subgroups and does not increase clinically relevant HLA antibody.