Hemorrhaging colitis,started hemorrhaging; so sick; They could hardly walk; Felt like almost collapsing; Had stomach ache; This case was received via an unknown source (no reference has been entered for a health authority or license partner) on 07-Dec-2021 and was forwarded to Moderna on 07-Dec-2021.    This spontaneous case was reported by a physician and describes the occurrence of ENTEROCOLITIS HAEMORRHAGIC (Hemorrhaging colitis,started hemorrhaging) in an 82-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 033F21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Diabetes, Drug allergy (Aspirin) and Latex allergy.    On 17-Nov-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In November 2021, the patient experienced ABDOMINAL PAIN UPPER (Had stomach ache). On 17-Nov-2021, the patient experienced ENTEROCOLITIS HAEMORRHAGIC (Hemorrhaging colitis,started hemorrhaging) (seriousness criteria hospitalization and medically significant), ILLNESS (so sick), MOBILITY DECREASED (They could hardly walk) and DIZZINESS (Felt like almost collapsing). The patient was hospitalized from 17-Nov-2021 to 22-Nov-2021 due to ENTEROCOLITIS HAEMORRHAGIC. The patient was treated with METRONIDAZOLE (intravenous) for Adverse event, at an unspecified dose and frequency and CIPROFLOXACIN (intravenous) for Adverse event, at an unspecified dose and frequency. At the time of the report, ENTEROCOLITIS HAEMORRHAGIC (Hemorrhaging colitis,started hemorrhaging), ILLNESS (so sick), MOBILITY DECREASED (They could hardly walk), ABDOMINAL PAIN UPPER (Had stomach ache) and DIZZINESS (Felt like almost collapsing) outcome was unknown.        The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Concomitant medications were not reported.  It was reported that patient administered 2 IV antibiotics (metronidazole and ciprofloxacin) along with fluids.  Patient reported that she became so sick, could hardly walk,  felt like almost collapsing, and when  went to bathroom, she started hemorrhaging  about  three and half hours after the vaccine around 4-4:40 pm. Then she went to ER and admitted to hospital for 6 days due to hemorrhaging colitis and she remained in bed after having treatment. Patient also  inquires about the ingredients of the vaccine in case there is something to explain her symptoms and also is concerned about getting the second dose.   Also mentioned about caller's spouse vaccination. Spouse's first dose was on 14Feb2021 and lot#002B, second dose was on 15Mar2021, lot#007M20A, and booster dose was on 17Nov2021, lot#033F21A and was tired after the second and booster dose.  Company comment This case concerns a 82-year-old female patient with no relevant medical history reported, who experienced the serious unexpected event of enterocolitis haemorrhagic. The event occurred the same day after the first dose of mRNA-1273. The rechallenge was not applicable since only information about the first dose was disclosed. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: This case concerns a 82-year-old female patient with no relevant medical history reported, who experienced the serious unexpected event of enterocolitis haemorrhagic. The event occurred the same day after the first dose of mRNA-1273. The rechallenge was not applicable since only information about the first dose was disclosed. The benefit-risk relationship of mRNA-1273 is not affected by this report.