Figure 4.

Influenza-specific serum antibodies following 2009-2010 TIV. Peripheral blood was obtained prior to (0) and at multiple time points within one month following vaccination with 2009 to 2010 seasonal trivalent influenza vaccine (TIV). Influenza-specific serum antibody was measured by hemagglutination inhibition assay (HAI) and geometric mean titer (GMT) determined. The red star indicates significant difference (P < 0.05) compared with healthy control (HC) group at same timepoint, the blue star indicates significant difference compared with the rheumatoid arthritis (RA) group at same timepoint. N, number of subjects measured for each group.