Serological response after anti-SARS-CoV-2 BNT162b2 vaccine in IBD patients on biological therapy: a monocentric case-control study

Inflammatory Bowel Disease (IBD) patients on biological therapy are receiving vaccines against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). However, it is unclear if IBD therapy could influence the response to this vaccine. In a case-control study, we assessed the antibody profiling after anti-SARS-CoV-2 BNT162b2 vaccine in IBD patients on biological therapy.We analyzed seroprevalence and antibody titer, after 14 weeks from the first BNT162b2 vaccine dose, in IBD patients on biological therapy and Health Care Workers (HCWs). In IBD patients, medical history and disease data were recorded.Eighty-two subjects were enrolled in this study. Among them, 40 were IBD patients on biological therapy and 42 were HCWs. All subjects developed an IgG anti-Spike antibody titer above the cut-off. IBD patients on biological therapy developed a lower antibody titer than HCWs (P0.00001). No differences were reported in patients who received at least one dose of the vaccine within a period of 7 days from the last biological drug administration, compared to all other IBD patients. A difference was found between patients who were on concomitant immunosuppressive therapy and patients on sole biological therapy (P = 0.0287). Patients with presence of any sign of disease activity (clinical, endoscopic or laboratory) showed a higher development of antibody titer compared to those in complete disease remission (P = 0,0468).Our data indicate that in IBD patients, treatment with biological therapies do not affect the seroprevalence but leads to a lower antibody titer development after anti-SARS-CoV-2 BNT162b2 vaccine.