We, and others, have shown that patients with IBD established on immunosuppressive drugs, including infliximab (anti-tumour necrosis factor, or anti-TNF monoclonal antibody) or tofacitinib (a pan Janus kinase, or JAK inhibitor), have significantly lower vaccine-induced antibody responses following two and three doses of COVID-19 vaccination compared to controls.9, 10, 11, 12 Anti-TNF treatment is also associated with accelerated loss of circulating vaccine-induced antibodies and anti-TNF treated patients are more likely to develop breakthrough infections after two doses of vaccine.8 Here, TNF is linked to infection.