Vaccination is a promising strategy to protect vulnerable groups like immunocompromised inflammatory bowel disease [IBD] patients from an infection with SARS-CoV-2. These patients may have lower immune responses. Little is known about the cellular and humoral immune response after a SARS-CoV-2 vaccination in IBD patients.

Totals of 28 patients with IBD and 27 age- and sex-matched healthy controls were recruited at Jena University Hospital. Blood samples were taken before, after the first, and in a subgroup of 11 patients after second dose of a SARS-CoV-2 vaccination. Cellular immune response, including IFN-γ and TNF-α response and antibody titres, were analysed.

Overall, 71.4% of the IBD patients and 85.2% of the controls showed levels of anti-SARS-CoV-2 antibodies above the cutoff of 33.8 BAU/ml [p = 0.329] after the first dose. Even in the absence of SARS-CoV-2 antibodies, IBD patients showed significant T cell responses after first SARS-CoV-2 vaccination compared with healthy controls, which was not influenced by different immunosuppressive regimens. Associated with the vaccination, we could also detect a slight increase of the TNF production among SARS-CoV-2-reactive T_H cells in healthy donorsn [HD] and IBD patients. After the second dose of vaccination, in IBD patients a further increase of humoral immune response in all but one patient was observed.

Already after the first dose of a SARS-CoV-2 vaccination, cellular immune response in IBD patients is comparable to controls, indicating a similar efficacy. However, close monitoring of long-term immunity in these patients should be considered.