ABSTRACT
Introduction: In the SARS-CoV2 mRNA vaccine trials, post-vaccination gastrointestinal (GI) symptoms were reported in 10-20% of participants. These symptoms could be perceived as inflammatory bowel disease (IBD) flare which could lead to patient anxiety, and unnecessary tests or treatment. We aimed to assess GI symptoms after SARS-CoV2 mRNA vaccination in patients with IBD relative to non-IBD healthcare workers (HCW). Methods: We assessed GI symptoms in adults with IBD and HCW at baseline and after each dose of a SARS-CoV-2 mRNA vaccine. We analyzed patient-reported IBD-specific disease activity (PRO2) after each dose (stool frequency (SF) and rectal bleeding for ulcerative colitis (UC), SF and abdominal pain for Crohn's disease (CD)). We also compared the frequency, severity, and duration of postvaccination GI symptoms in IBD patients compared to HCW. Severity was defined by impact on daily activities (mild, did not interfere;moderate, some interference;severe, prevented routine activity;extreme, required hospitalization). Severe and extreme were combined and designated as severe+. Duration was classified as<2 days, 2-7 days, or>7 days. Results: Post-vaccination GI symptoms were assessed after dose 1 (D1) (1391 IBD, 933 HCW) and dose 2 (D2) (1271 IBD, 884 HCW) (Table). About 60% of IBD and>99% of HCW received the BNT162b vaccine (Pfizer);the remainder received mRNA-1273 (Moderna). New GI symptoms after D1 were more frequent among IBD than HCW (6.0% vs 2.9%, p=0.001) but not after D2 (12.1% vs 12.7%, p=NS). Relative to HCW, IBD patients reported more diarrhea (3.8% vs. 1% (p<0.001) after D1 and 7.5% vs 4.2% (p=0.003) after D2) and abdominal pain (2.2% vs. 0.4% (p=0.001) after D1 and 6.2% vs 3% (p=0.002) after D2). Severe1 symptoms were noted in 1.5% IBD and 0.3% HCW (p=NS) after D1 and in 3.3% IBD and 0.1% HCW (p<0.001) after D2 (Figure 1). Longer GI symptom duration was more common in IBD than HCW after D1 (2.1% vs 0.5%, p=0.002) and D2 (5.4% vs. 2.1%, p<0.001). Among 423 CD and 300 UC patients with PRO2 data, 71%, 68%, and 65% of CD and 86%, 86%, and 83% of UC were in clinical remission at baseline, after D1, and after D2, respectively. Conclusion: The frequency of GI symptoms in IBD was greater than HCW after D1, but similar after D2. More severe and longer duration of GI symptoms were noted in a small number of IBD patients. Reassuringly, the mRNA vaccines do not seem to increase the risk of a disease flare in the vast majority of IBD patients.