Varicella zoster virus encephalitis: a potentially serious complication during treatment with vedolizumab.

Vedolizumab is a monoclonal antibody that has demonstrated efficacy and a good safety profile in patients with inflammatory bowel disease. Varicella zoster virus encephalitis is a potentially serious complication not previously described with its use, highlighting the importance of vaccination, as well as early diagnosis and treatment of infections in this type of patients.