Keywords: Crohn's disease, ulcerative colitis, infliximab, vedolizumab, SARS-CoV-2, trough levels © 2023 Lelong, Régis, Coste-Burel, Rimbert, Bressollette-Bodin, Nancey, Bouguen, Allez, Serrero, Caillo, Rouillon, Blanc, Laharie, Olivier, Peyrin-Biroulet, Dib, De Maissin, Montuclard, Trang-Poisson, Vavasseur, Gallot, Berthome, Braudeau, Chevreuil, Bourreille and Le Berre. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).