Antibody Response to SARS-CoV-2 Vaccination in Patients with Inflammatory Bowel Disease: Results of a Single-Center Cohort Study in a Tertiary Hospital in Germany.

BACKGROUND: COVID-19 is a viral disease caused by severe acute respiratory syndrome corona virus 2 (SARS-CoV-2), first described in 2019, with a significant impact on everyday life since then. In December 2020, the first vaccine against COVID-19 from BioNTech/Pfizer was approved for the first time. However, little is known about the immune response to vaccination in patients with inflammatory bowel disease (IBD) and immunomodulators or biologics. The aim of our study was to investigate antibody response to SARS-CoV-2 vaccination in patients with IBD receiving immunomodulators or biologics compared to healthy controls. METHODS: This was a single-center study with a retrospective observational design. Seventy-two patients with ulcerative colitis or Crohn's disease were included. Matching data from 72 healthy employees of our hospital were used as the control group. Data were matched by propensity score to patients with IBD. Blood samples were taken from both groups for antibody response, and both groups received an accompanying questionnaire. RESULTS: Sixty-five (90.3%) patients of the IBD group reported taking immunomodulatory therapy. The mean antibody level for all IBD patients was 1,257.1 U/mL (standard deviation [SD] 1,109.626) in males and 1,500.1 U/mL (SD 1142.760) in female IBD patients after full vaccination. Compared to the healthy group, reduced antibody response could be detected (IBD group 1,383.76 U/mL SD 1,125.617; control group 1,885.65 U/mL SD 727.572, p < 0.05). In this group, blood samples were taken with an average of 61.9 days after the first vaccination. There was no vaccination failure in the IBD group after 2 vaccinations. After the first vaccination, side effects, including muscle pain, pain at the injection site, and fatigue, were reported more often in IBD patients than in the control group (total symptoms IBD group 58.3%, control group 34.5%, p < 0.007). The opposite occurred after the second vaccination when side effects were higher in the control group (total symptoms IBD group 55.4%, control group 76%, p = 0.077). There was a trend to a reduced immune response in elderly patients. Disease duration and concomitant immunomodulatory therapy (TNF-alpha blockers, interleukin inhibitors, integrin inhibitors, methotrexate, or azathioprine) had no impact on the immune response. However, longer time to last medication given and time passed to vaccination in patients with IBD seems to have a positive impact on antibody levels. CONCLUSION: Overall, we could show a high antibody response to vaccination with COVID-19 in all patients with IBD after 2 vaccinations. Vaccination was well tolerated, and no other adverse events were detected. Concomitant immunomodulatory therapy (TNF-alpha blockers, interleukin inhibitors, integrin inhibitors, methotrexate, or azathioprine) had no impact on seroconversion. Further evaluation of antibody titers over time is mandatory to detect early the need for re-vaccination in these patients.

Comparison of the Development of SARS-Coronavirus-2-Specific Cellular Immunity, and Central Memory CD4+ T-Cell Responses Following Infection versus Vaccination.

Memory T-cell responses following infection with coronaviruses are reportedly long-lived and provide long-term protection against severe disease. Whether vaccination induces similar long-lived responses is not yet clear since, to date, there are limited data comparing memory CD4+ T-cell responses induced after SARS-CoV-2 infection versus following vaccination with BioNTech/Pfizer BNT162b2. We compared T-cell immune responses over time after infection or vaccination using ELISpot, and memory CD4+ T-cell responses three months after infection/vaccination using activation-induced marker flow cytometric assays. Levels of cytokine-producing T-cells were remarkably stable between three and twelve months after infection, and were comparable to IFNγ+ and IFNγ+IL-2+ T-cell responses but lower than IL-2+ T-cell responses at three months after vaccination. Consistent with this finding, vaccination and infection elicited comparable levels of SARS-CoV-2 specific CD4+ T-cells after three months in addition to comparable proportions of specific central memory CD4+ T-cells. By contrast, the proportions of specific effector memory CD4+ T-cells were significantly lower, whereas specific effector CD4+ T-cells were higher after infection than after vaccination. Our results suggest that T-cell responses-as measured by cytokine expression-and the frequencies of SARS-CoV-2-specific central memory CD4+T-cells-indicative of the formation of the long-lived memory T-cell compartment-are comparably induced after infection and vaccination.