Background: Medical treatment of inflammatory bowel disease (IBD) has evolved significantly, and treatment with immunomodulators is recommended. These medications may alter the patient’s immune response and increase the risk of opportunistic infections. Our aim was to evaluate the prevalence and the incidence of acute or chronic HEV infection in IBD patients under immunomodulatory treatment. Patients and Methods: We conducted a retrospective, multicenter, observational study between 2017 and 2018. IBD outpatients hospitalized for the infusion of immunomodulators were included in 16 French centers. During their daily hospitalization, blood samples were drawn for HEV serology (IgM and IgG) and HEV RNA detection. Results: A total of 488 patients were included, of which 327 (67%) patients had Crohn’s disease and 161 (33%) ulcerative colitis. HEV IgM was detected in 3 patients, but HEV RNA was undetectable in all patients. The HEV IgG seroprevalence rate was 14.2%. IgG-positive patients were older at sampling (p = 0.01) and IBD diagnosis (p = 0.03), had higher seafood consumption (p = 0.01) and higher doses of azathioprine (p = 0.03). Ileal and upper digestive tract involvement was more frequent in IgG-positive patients (p = 0.009), and ileocolic involvement was more frequent in IgG-negative patients (p = 0.01). Under multivariate analysis, age > 50 years [OR: 2.21 (1.26, to 3.85), p = 0.004] was associated with previous HEV infection. Conclusion: Systematic screening for HEV infection is not needed among IBD patients on immunomodulatory medications. However, in the event of abnormal liver test findings, HEV should be part of the classic diagnostic assessment.
