Booster influenza vaccination does not improve immune response in adult inflammatory bowel disease patients treated with immunosuppressives: a randomized controlled trial

Background This research was conducted is to assess the effect of booster doses of the trivalent influenza vaccine in adult inflammatory bowel disease (IBD) patients treated with anti-tumor necrosis factor (TNF)-α agents and/or immunomodulators. Methods Adult IBD patients and healthy individuals were subcutaneously administered the trivalent influenza vaccine. They were randomized into two groups: the single vaccination group and the two vaccination booster group. Blood samples were collected, and the antibody titers against each influenza strain were determined by hemagglutination inhibition at 3 different time points (pre-vaccination, 3 weeks post-vaccination, and after the flu season) in the single vaccination group and at 4 time points (pre-vaccination, 3 weeks post-first vaccination, 3 weeks post-second vaccination, and after the flu season) in the booster vaccination group. Results Seventy-eight IBD patients and 11 healthy controls were randomized into the single vaccination group and the booster vaccination group. Twenty-nine patients received immunomodulators; 21 received anti-TNF-α agents; and 28 received a combination of both. No significant differences were observed in the evaluated immune response parameters between 3 weeks post-vaccination in the single vaccination group and 3 weeks post-second vaccination in the booster vaccination group (geometric mean titers: H1N1, p = 0.09; H3N2: p = 0.99; B: p = 0.94). A higher pre-vaccination titer was significantly associated with sufficient seroprotection rate after vaccination for the H1N1 strain (odds ratio 11.93, p = 0.03). Conclusions The second booster of trivalent influenza vaccination did not improve the immune response in adult IBD patients who were treated with immunomodulators and/or anti-TNF-α agents.