IBS became much worse post vaccination; Caller doesnt want to do second dose of vaccine because of side effect; diarrhea; extreme gut pain; Had flu like symptoms; Fatigue; Headache; Nausea; Fever; light nausea; Loose stool; GI issues/ Digestive problems; Stomach cramps and pain; Depression; This spontaneous case was reported by a consumer and describes the occurrence of IRRITABLE BOWEL SYNDROME (IBS became much worse post vaccination), PRODUCT DOSE OMISSION ISSUE (Caller doesnt want to do second dose of vaccine because of side effect), INFLUENZA LIKE ILLNESS (Had flu like symptoms), GASTROINTESTINAL PAIN (extreme gut pain) and ABDOMINAL DISCOMFORT (GI issues/ Digestive problems) in a 64-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 002BZ1A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Allergy to plants (Allergy to Dandelion greens), Mercury sensitivity (Allergy to Mercury), Food allergy (Allergy to gluten) and Irritable bowel syndrome (Became much worse post vaccination) since 2013. Concomitant products included THYROID (ARMOUR THYROID) from 1998 to an unknown date for Hypothyroidism, CHOLESTYRAMINE and VALACICLOVIR HYDROCHLORIDE (VALTREX) for an unknown indication.    On 19-Mar-2021 at 11:50 AM, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 19-Mar-2021, the patient experienced ABDOMINAL DISCOMFORT (GI issues/ Digestive problems), ABDOMINAL PAIN UPPER (Stomach cramps and pain), DEPRESSION (Depression), DIARRHOEA (Loose stool) and NAUSEA (light nausea). On 20-Mar-2021, the patient experienced INFLUENZA LIKE ILLNESS (Had flu like symptoms), FATIGUE (Fatigue), HEADACHE (Headache), NAUSEA (Nausea) and PYREXIA (Fever). On 23-Mar-2021, the patient experienced GASTROINTESTINAL PAIN (extreme gut pain) and DIARRHOEA (diarrhea). On an unknown date, the patient experienced IRRITABLE BOWEL SYNDROME (IBS became much worse post vaccination) and PRODUCT DOSE OMISSION ISSUE (Caller doesnt want to do second dose of vaccine because of side effect). The patient was treated with BISMUTH SUBSALICYLATE (PEPTO-BISMOL INSTACOOL) at an unspecified dose and frequency; TRAMADOL at an unspecified dose and frequency; PARACETAMOL (TYLENOL) at an unspecified dose and frequency; LAMOTRIGINE (LAMICTAL) for Depression, at an unspecified dose and frequency and CALCIUM CARBONATE (ANTACID [CALCIUM CARBONATE]) at an unspecified dose and frequency. On 21-Mar-2021, INFLUENZA LIKE ILLNESS (Had flu like symptoms), FATIGUE (Fatigue), HEADACHE (Headache), NAUSEA (Nausea) and PYREXIA (Fever) had resolved. At the time of the report, IRRITABLE BOWEL SYNDROME (IBS became much worse post vaccination), ABDOMINAL DISCOMFORT (GI issues/ Digestive problems), ABDOMINAL PAIN UPPER (Stomach cramps and pain), DEPRESSION (Depression), DIARRHOEA (Loose stool) and NAUSEA (light nausea) outcome was unknown, PRODUCT DOSE OMISSION ISSUE (Caller doesnt want to do second dose of vaccine because of side effect) had resolved and GASTROINTESTINAL PAIN (extreme gut pain) and DIARRHOEA (diarrhea) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Colonoscopy: inconclusive (Inconclusive) No problems were seen other than some inflammation.. On an unknown date, Endoscopy: inconclusive (Inconclusive) No problems were seen other than some inflammation..     mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was withdrawn on an unknown date.       Most recent FOLLOW-UP information incorporated above includes: On 13-Apr-2021: Follow up received on 13-Apr-2021, Added treatment drugs Pepto-Bismol , Tramadol and added newevents extreme gut pain, diarrhea. On 22-Jun-2021: Follow up received on 22-Jun-2021, Reporter address added, added laboratory details, added treatment drugs Lamictal, antacid, added new events. On 28-Jul-2021: Patient demographic details were updated. Medical history updated - Current condition and allergic information were added. Dosage information of the concomitant drug ARMOUR THYROID were updated. New event Irritable bowel syndrome aggravated added. Event outcome updated for the events Gastro intestinal pain and Diarrhea from Unknown to Not recovered/Not resolved.