Expanded Access to Vedolizumab for Children and Teenagers With Ulcerative Colitis or Crohn's Disease in the USA

Inclusion Criteria: 1. The participant has UC or CD and is of age less than (\<) 18 years at the time of final treatment completion of Vedolizumab-2005. 2. The participant is demonstrating continued clinical benefit from vedolizumab IV for the treatment of UC or CD that outweighs possible risks. 3. The participant, participant's legally authorized representative, or adult caregiver is informed of the nature of this expanded access program and has provided signed and dated written informed consent and/or pediatric assent. 4. The participant does not have any condition, including laboratory test result, that in the opinion of the investigator may compromise the participant's safety. 5. The participant does not have a known hypersensitivity to vedolizumab or its components. 6. According to the participant's treating healthcare professional (HCP): there are no comparable and satisfactory alternative treatment options in the local market, or the participant would be negatively affected without continued access to vedolizumab IV. 7. Female participants of childbearing potential only: * The participant has agreed to be abstinent or agreed to comply with the applicable contraceptive requirements of this protocol for the duration of the expanded access program and for 18 weeks after completion of the last dose of vedolizumab. * The participant is not pregnant or breastfeeding. * The participant will not donate ova during the course of the program and for 18 weeks after the last dose of vedolizumab. 8. Male participants only: * The participant has agreed to comply with the applicable contraceptive requirements of this protocol for the duration of the expanded access program and for 18 weeks after the last dose of vedolizumab. * The participant has agreed to not donate sperm during the course of the program and for 18 weeks after the last dose of vedolizumab. Exclusion Criteria: -No specific exclusion criteria.