Ulcerative colitis; Swollen knee and leg; Severe cramping on the intestines; Pretty sick for 28 days; Swelling Left leg/Swelling of legs; Severe fatigue; abdominal cramp; loose stool; Sore arm; Very low grade  fever (99. something); This spontaneous case was reported by a consumer and describes the occurrence of COLITIS ULCERATIVE (Ulcerative colitis), JOINT SWELLING (Swollen knee and leg), GASTROINTESTINAL PAIN (Severe cramping on the intestines), DIARRHOEA (loose stool) and ILLNESS (Pretty sick for 28 days) in a 56-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 003B21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Ulcerative colitis (Had been in remission for 4 years until Moderna shot) since 18-Jan-1999 and Drug allergy. Concomitant products included MESALAZINE (DELZICOL) from 20-Jan-1999 to an unknown date for Ulcerative colitis.   On 30-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 30-Mar-2021, the patient experienced MYALGIA (Sore arm) and PYREXIA (Very low grade fever (99. something)). On 04-Apr-2021, the patient experienced DIARRHOEA (loose stool) and ABDOMINAL PAIN (abdominal cramp). On 06-Apr-2021, the patient experienced PERIPHERAL SWELLING (Swelling Left leg/Swelling of legs) and FATIGUE (Severe fatigue). On an unknown date, the patient experienced COLITIS ULCERATIVE (Ulcerative colitis), JOINT SWELLING (Swollen knee and leg), GASTROINTESTINAL PAIN (Severe cramping on the intestines) and ILLNESS (Pretty sick for 28 days). On 01-May-2021, DIARRHOEA (loose stool) and ABDOMINAL PAIN (abdominal cramp) had resolved. On 30-Jun-2021, PERIPHERAL SWELLING (Swelling Left leg/Swelling of legs) had resolved. On 05-Jul-2021, FATIGUE (Severe fatigue) had resolved. At the time of the report, COLITIS ULCERATIVE (Ulcerative colitis), JOINT SWELLING (Swollen knee and leg), GASTROINTESTINAL PAIN (Severe cramping on the intestines), ILLNESS (Pretty sick for 28 days), MYALGIA (Sore arm) and PYREXIA (Very low grade  fever (99. something)) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Body temperature: high (High) 99 something.   The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.   No treatment medications were reported.  The patient received first dose Moderna COVID-19 vaccine on 30-Mar2021 and on left, non-dominant arm and reported a swollen knee and leg was the same side vaccine was administered. It started with a sore arm, very low-grade fever (99. something), and then 4 to 5 days in the patient experienced severe cramping on the intestines and loose stool. Later the patient said the swelling on leg and knee started. The patient has an auto immune condition, ulcerative colitis. Was on remission until took the Moderna and it went back. Patient wanted to be fully vaccinated but was concerned as it was pretty sick for 28 days.  It was reported that the patient experienced on first day of vaccine, mild fever and sore arm. Good after that. 4 to 5 days in severe abdominal cramping.   Company Comment: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.   Most recent FOLLOW-UP information incorporated above includes: On 01-Oct-2021: follow up received on 01-OCT-2021 added Patient Information, Relevant medical history, Events and information (outcome, start date and stop) of evens updated.; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.