Colon fistula drainage due to infection on the site; Gastrintestinal infection; Chills; Fever; Headache; This spontaneous case was reported by a physician (subsequently medically confirmed) and describes the occurrence of COLONIC FISTULA (Colon fistula drainage due to infection on the site), GASTROINTESTINAL INFECTION (Gastrintestinal infection), CHILLS (Chills), PYREXIA (Fever) and HEADACHE (Headache) in a 34-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.    Co-suspect product included non-company product ADALIMUMAB (HUMIRA) solution for injection for Crohn's disease.    The patient's past medical history included Intestinal fistula repair (Colonic Fistula surgery) on 01-Sep-2017 and Fistula repair (colonic fistula drainage insertion surgery) on 28-Sep-2017. Concurrent medical conditions included Crohn's disease.   On 28-Nov-2017, the patient started ADALIMUMAB (HUMIRA) (Subcutaneous) 40 mg once a week. On an unknown date, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On an unknown date, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On an unknown date, the patient experienced COLONIC FISTULA (Colon fistula drainage due to infection on the site) (seriousness criterion medically significant), GASTROINTESTINAL INFECTION (Gastrintestinal infection), CHILLS (Chills), PYREXIA (Fever) and HEADACHE (Headache). At the time of the report, COLONIC FISTULA (Colon fistula drainage due to infection on the site) was resolving, GASTROINTESTINAL INFECTION (Gastrintestinal infection), CHILLS (Chills) and HEADACHE (Headache) outcome was unknown and PYREXIA (Fever) had resolved. Not Provided      For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   No concomitant medications reported by investigator.  On 02-MAR-2021, patient had a surgery to remove the colon fistula drainage due to infection on the site. She was doing better with colon fistula but still had some draining. No other treatment information was provided by the reporter for symptoms like chills, fever, headache. This case concerns a 34-year-old female with PMH of Crohn's disease on adalimumab, who had serious unexpected events of gastrointestinal infection, colonic fistula, pyrexia, chills, and headache. Event onset with unknown latency after second dose mRNA-1273. Events resolved. Based on current available information and temporal association between the use of the product and the start date of the event, a causal relationship cannot be excluded.  Action taken with mRNA-1273 in response to events was not applicable.   Most recent FOLLOW-UP information incorporated above includes: On 27-Apr-2021: Additional information received included patient  demographics,  medical history, dose  unit and therapy start date of co-suspect drug,   vaccine second dose , adverse  event Fistula drainage was deleted as per intial  and  gastrointestinal infection was added and outcome was unknown. Treatment surgery added in narrative description.; Sender's Comments: This case concerns a 34-year-old female with PMH of Crohn's disease on adalimumab, who had serious unexpected events of gastrointestinal infection, colonic fistula, pyrexia, chills, and headache. Event onset with unknown latency after second dose mRNA-1273. Events resolved. Based on current available information and temporal association between the use of the product and the start date of the event, a causal relationship cannot be excluded.