Wisniewski A, Kirchgesner J, Seksik P, et al. - In patients with inflammatory bowel diseases (IBD), researchers evaluated the incidence and risk factors for systemic serious viral infections. Patients were identified that were followed for IBD in 2005–2014 outside the context of organ transplantation, HIV infection or chronic viral hepatitis using MICISTA, a database detailing prospective characteristics and complications of IBD. Among 2645 patients followed for 15,383 person-years, 31 patients with serious viral infections were identified. Thirteen cases of cytomegalovirus, 10 Epstein–Barr virus, 5 varicella zoster virus and 3 herpes simplex virus infections were observed. Compared with the general population, the incidence of systemic serious viral infections in patients with IBD was tripled. The main drivers of the risk were clinically active IBD and exposure to thiopurines. There were no fatalities.