Influenza vaccine antibody responses in lung transplant recipients

Lung transplant recipients are at high risk of morbidity and mortality from influenza infection because of altered lung physiology and immunosuppression. Annual influenza immunization is recommended, but the ability to mount an antibody response may be limited by immunosuppressant medications.

To compare the antibody response rate to influenza vaccine in lung transplant recipients to healthy controls.

Open label study.

Lung transplant clinic and General Clinical Research Center at a university hospital.

Sixty-eight single and bilateral lung transplant recipients and 35 healthy controls were enrolled in October and November 2002.

Each individual underwent blood sampling before receiving the 2002-2003 influenza vaccine and 4 weeks later. Influenza antibody concentrations were measured by hemagglutination inhibition assay. Vaccine response rates (antibody concentration >40 hemagglutination units and at least 4-fold increase in antibody concentration) were compared using chi2. The influence of specific immunosuppressants on vaccine response was compared.

The influenza vaccine response rate for lung transplant recipients was 29/68 (43%) and 22/35 (63%) for the healthy individuals (P < .05; chi2). Among the recipients, mycophenolate mofetil was associated with poorer influenza vaccine antibody response (> 40 hemagglutination units) (62% vs 91%; P = .01), whereas sirolimus (91% vs 63%; P = .02) was associated with better influenza antibody response compared to those not taking mycophenolate mofetil or sirolimus, respectively.

Lung transplant recipients had lower influenza vaccine response rates than healthy individuals. Influenza vaccine antibody response is influenced by concomitant administration of mycophenolate mofetil or sirolimus. Future studies should measure protection from influenza infection conferred by immunization and alternative vaccination strategies.