Lack of inflammatory bowel disease flare-up following two-dose BNT162b2 vaccine: a population-based cohort study

We read with interest the recent paper by Cannatelli et al1 describing the adverse events (AEs) following COVID-19 vaccination from a large inflammatory bowel disease (IBD) cohort, which showed that patients with IBD had a similar rate of reported AEs to the general population but with a slightly higher rate of self-limiting gastrointestinal symptoms. However, the effects of COVID-19 vaccine on IBD activity, particularly severe flare resulting in hospitalisation and the interplay with the use of immunotherapy remain unknown. To address these questions, we analysed the territory-wide electronic medical records with vaccination linkage database in Hong Kong2–7 to examine the association between BNT162b2 vaccination and IBD flare.