Ulcerative Colitis Flare; This literature-non-study case was reported in a literature article and describes the occurrence of COLITIS ULCERATIVE (Ulcerative Colitis Flare) in a 50-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.     Concurrent medical conditions included Ulcerative colitis (Patient has a history of UC in remission of 4 years on mesalamine.).   On an unknown date, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced COLITIS ULCERATIVE (Ulcerative Colitis Flare) (seriousness criteria hospitalization and medically significant). The patient was treated with MESALAMINE for Ulcerative colitis, Bloody stool and Diarrhea, at a dose of 1 UNK and METHYLPREDNISOLONE for Ulcerative colitis, Bloody stool and Diarrhea, at a dose of UNK dosage form. At the time of the report, COLITIS ULCERATIVE (Ulcerative Colitis Flare) was resolving. Possible    DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Computerised tomogram abdomen: contiguous colitis Abdominopelvic CT demonstrated contiguous colitis.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered COLITIS ULCERATIVE (Ulcerative Colitis Flare) to be related.    Patient presented with diarrhea and bloody stools that developed 1 week after dose 1. Patient had worsening diarrhea 1 week following vaccination that progressed to hematochezia.  Patient received both doses of the mRNA-1273 mRNA vaccine, 28 days apart.  Her symptoms improved in 2 days, and she was discharged on a steroid taper.  Patient was in symptomatic remission on 5-ASA maintenance agents for several years prior to vaccination.   Author discussed that the lack of clear alternate environmental changes in this patient suggests provocation of flare by the inflammatory response following vaccination and concluded that recommendations from an international expert consensus favors vaccination of patients with UC. In addition, recent literature demonstrates strong immunologic response following vaccination of patients with UC despite concurrent use of biologic agents. Consideration should be given to pre-treatment of patients with UC in remission to decrease risk of flare.  Company comment: This is a literature-non-study case for a 50-year-old female patient, with medical history of colitis ulcerative in remission, who experienced the serious unexpected event of Colitis ulcerative flare a week after first dose of mRNA-1273. The patient experienced  worsening diarrhea 1 week following vaccination that progressed to hematochezia. The patient was hospitalized and treated with mesalamine and methylprednisolone. Her symptoms improved in 2 days, and she was discharged on a steroid taper. The re-challenge is unknown since no information regarding events after second dose was disclosed. Patient´s medical history remains a contributing factor. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 02-Dec-2021: Follow up received by safety on 03-Dec-2021 included an Email received from Regulatory Authority team and contains new information.; Sender's Comments: This is a literature-non-study case for a 50-year-old female patient, with medical history of colitis ulcerative in remission, who experienced the serious unexpected event of Colitis ulcerative flare a week after first dose of mRNA-1273. The patient experienced  worsening diarrhea 1 week following vaccination that progressed to hematochezia. The patient was hospitalized and treated with mesalamine and methylprednisolone. Her symptoms improved in 2 days, and she was discharged on a steroid taper. The re-challenge is unknown since no information regarding events after second dose was disclosed. Patient´s medical history remains a contributing factor. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.