TNF and inflammatory bowel disease: The aim of this observational prospective study was to monitor the trend of development of antibodies against COVID-19 after vaccination in patients with IBD, who are being treated by immunosuppressive and/or biological therapy from the group of Tumor necrosis factor α inhibitors (antiTNFα), and demonstrate whether any type of chronic immunosuppressive/biological therapy for IBD was associated with poorer production of antibodies against COVID-19.