The humoral immune response to the inactivated influenza A (H1N1) 2009 monovalent vaccine in patients with Type 2 diabetes mellitus in Korea

AIMS: We evaluated the antibody response to a single-dose adjuvanted, inactivated, pandemic H1N1 influenza vaccination in patients with diabetes and assessed factors associated with the failure to induce antibody responses. METHODS: Eighty-two patients with Type 2 diabetes were vaccinated and antibody responses were determined with haemagglutination inhibition assay and anti-haemagglutinin antibody ELISA. RESULTS: Among 70 antibody-negative patients at baseline, 34 (48.6%) achieved seroconversion; 28 (60.9%) in the young adults group and six (25%) in the elderly group acquired H1N1-specific antibodies. Patients in the older age range or with longer duration of diabetes had a lower seroconversion rate. CONCLUSIONS: Our data show low cross-reactive antibody carrying rate and low seroconversion rate in patients with diabetes. Until larger-scale, case-controlled trials become available, older patients and patients with a longer duration of diabetes should be considered for the two-dose vaccination or have antibody titres measured after the first vaccination.