During the 2013-2014 influenza season, CKD patients undergoing HD participated in the study. The patients were randomized into two groups (MF59-adjuvanted vaccine group or non-adjuvanted vaccine group) and were immunized with the respective vaccine. Sera were collected prior to vaccination and at 1and 6 months post vaccination. Levels of hemagglutination inhibition (HI) antibodies were measured.