Patients with Crohn's disease (CD) and ulcerative colitis (UC) are often treated with medications that suppress the immune system. These patients are therefore at increased risk for developing infections, such as influenza, pneumonia, and hepatitis B, which may be prevented by vaccination. While awareness is increasing among gastroenterologists of the importance of vaccinations in the IBD patient, there continues to be some question of the effectiveness of vaccination in immunosuppressed patients. It has been previously shown that patients on immunosuppressive therapy with certain biologic medications (the TNF-blockers: infliximab and adalimumab) had an impaired immune response to vaccination as compared to healthy controls, as the mechanism of immunosuppression for these agents is systemic. Vedolizumab, a biologic medication for CD and UC approved in May 2014, targets the α4β7 integrin, a key component of gut immunity, and as such it has been hypothesized that with this agent effects are gut specific. There is limited data that suggests that in healthy patients given vedolizumab do not have an altered response to parentally administered vaccines, however there are no studies in the CD and UC population describing this. Additionally, IBD patients treated with vedolizumab are frequently also on concomitant therapy with an immunomodulator (6-mercaptopurine, azathioprine, or methotrexate), and these patients ability to mount an immune response has not been demonstrated.