I was admitted to the hospital with an ulcerative colitis flare up; I had non stop diarrhea, fatigue, exhaustion; I had non stop diarrhea, fatigue, exhaustion; Inappropriate schedule of vaccine administered (first dose on 22-Apr-2021 and second on 08-Oct-2021); This spontaneous case was reported by an other health care professional and describes the occurrence of COLITIS ULCERATIVE (I was admitted to the hospital with an ulcerative colitis flare up), DIARRHOEA (I had non stop diarrhea, fatigue, exhaustion) and FATIGUE (I had non stop diarrhea, fatigue, exhaustion) in a 29-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 007CZ1A and 050E21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Ulcerative colitis. Concomitant products included VEDOLIZUMAB (ENTYVIO) for an unknown indication.   On 22-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 08-Oct-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 08-Oct-2021, the patient experienced COLITIS ULCERATIVE (I was admitted to the hospital with an ulcerative colitis flare up) (seriousness criteria hospitalization and medically significant), DIARRHOEA (I had non stop diarrhea, fatigue, exhaustion) (seriousness criterion hospitalization), FATIGUE (I had non stop diarrhea, fatigue, exhaustion) (seriousness criterion hospitalization) and INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Inappropriate schedule of vaccine administered (first dose on 22-Apr-2021 and second on 08-Oct-2021)). The patient was hospitalized on 08-Oct-2021 due to COLITIS ULCERATIVE, DIARRHOEA and FATIGUE. The patient was treated with LOPERAMIDE for Adverse event, at an unspecified dose and frequency and PREDNISONE for Adverse event, at an unspecified dose and frequency. On 08-Oct-2021, INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Inappropriate schedule of vaccine administered (first dose on 22-Apr-2021 and second on 08-Oct-2021)) had resolved. At the time of the report, COLITIS ULCERATIVE (I was admitted to the hospital with an ulcerative colitis flare up), DIARRHOEA (I had non stop diarrhea, fatigue, exhaustion) and FATIGUE (I had non stop diarrhea, fatigue, exhaustion) had not resolved.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   The patient endured an ulcerative colitis that caused fatigue, diarrhea and a hospitalization. The symptoms are ongoing.  Company Comment: This case concerns a 29 year-old female patient with a history of ulcerative colitis on vedolizumab who experienced the unexpected serious event of ulcerative colitis, diarrhea and fatigue. The event occurred approximately TIME TO ONSET FROM FIRST DOSE after the first dose of Moderna COVID-19 Vaccine. The rechallenge was unknown as only the first dose was administered. The medical history of ulcerative colitis remains a confounder for ulcerative colitis. The benefit-risk relationship of Moderna COVID-19 Vaccine is not affected by this report.; Sender's Comments: This case concerns a 29 year-old female patient with a history of ulcerative colitis on vedolizumab who experienced the unexpected serious event of ulcerative colitis, diarrhea and fatigue. The event occurred approximately TIME TO ONSET FROM FIRST DOSE after the first dose of Moderna COVID-19 Vaccine. The rechallenge was unknown as only the first dose was administered. The medical history of ulcerative colitis remains a confounder for ulcerative colitis. The benefit-risk relationship of Moderna COVID-19 Vaccine is not affected by this report.