COVID-19 was first described in 2019, with significant impact on everyday life since then. In 2020, the first vaccine against COVID-19 was approved. Little is known about immune response to vaccination in patients with inflammatory bowel disease (IBD). Aim of our study was to investigate antibody response to SARS-CoV-2 vaccination in IBD patients receiving immunomodulators/biologics compared to healthy controls. This was a single-center retrospective study. 72 patients with IBD were included. Data from 72 healthy employees were used as control group matched by propensity score. Blood samples were analyzed for antibody response. 65 (90.3%) patients of the IBD group received immunomodulatory therapy. Mean antibody level for IBD patients was 1257.1 U/ml (SD 1109.626) in males and 1500.1 U/ml (SD 1142.760) in females (reduced antibody response IBD group 1383.76 U/ml SD 1125.617; control group 1885.65 U/ml SD 727.572, p < 0.05)). There was no vaccination failure in IBD group. After first vaccination, side effects were reported more often in IBD patients (total symptoms IBD group 58.3 %, control group 34.5 %, p < 0.007) with the opposite after the second vaccination (total symptoms IBD group 55.4 %, control group 76 %, p = 0.077)). There was a trend to reduced immune response in elderly. Disease duration and immunomodulatory therapy had no impact on immune response. Longer time to last medication given and time passed to vaccination in IBD group seem to have a positive impact on antibody levels. High antibody response to vaccination in all patients with IBD was seen. Vaccination was well tolerated. Concomitant immunomodulatory therapy had no impact on seroconversion. Antibody levels in the IBD group were lower compared to control group.S. Karger AG, Basel.
