Wound up with diverticulitis/pyrexia/abscess; This spontaneous case was reported by a consumer and describes the occurrence of DIVERTICULITIS (Wound up with diverticulitis/pyrexia/abscess) in a female patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.     Concurrent medical conditions included Seasonal allergy (Seasonal allergies and allergies shots), Diverticulitis (Mild case of diverticulitis 10 years ago, better in a couple of days.) and Hashimoto's disease (Hashimoto since 2014) since 2014.   On 09-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 06-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 13-Dec-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced DIVERTICULITIS (Wound up with diverticulitis/pyrexia/abscess) (seriousness criteria hospitalization and medically significant). The patient was hospitalized for 8 days due to DIVERTICULITIS. At the time of the report, DIVERTICULITIS (Wound up with diverticulitis/pyrexia/abscess) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Computerised tomogram: showed abscess Showed abscess.         Patient took allergic shots previously. Concomitant medication was not provided. No other vaccines were given within 1 month prior to Moderna COVID-19 vaccine. She never had COVID + test or diagnosis. Patient was treated with IV antibiotics for 8 days in hospital. It was reported that symptoms were getting worse.  Company comment: This is a spontaneous case concerning a female patient of unknown age with relevant concurrent medical condition of diverticulitis, who experienced the unexpected serious (medically significant and hospitalization) event of diverticulitis. The event exact occurrence was unknown but stated that the event aggravates after the third dose of mRNA-1273 vaccine administration. The event was described as, patient experienced mild diverticulitis 10 years ago and was better after couple of days. After the third dose of mRNA-1273 vaccine, patient experienced fever on the same night and wound up with diverticulitis. Patient sought consult and at the emergency room unspecified CAT scan revealed abscess. Patient was subsequently admitted for 8 days and received IV antibiotics. No other information surrounding the event was reported. The concurrent medical condition of diverticulitis remain confounder for the event. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   This case was linked to MOD-2022-568554.   Reporter did not allow further contact; Sender's Comments: This is a spontaneous case concerning a female patient of unknown age with relevant concurrent medical condition of diverticulitis, who experienced the unexpected serious (medically significant and hospitalization) event of diverticulitis. The event exact occurrence was unknown but stated that the event aggravates after the third dose of mRNA-1273 vaccine administration. The event was described as, patient experienced mild diverticulitis 10 years ago and was better after couple of days. After the third dose of mRNA-1273 vaccine, patient experienced fever on the same night and wound up with diverticulitis. Patient sought consult and at the emergency room unspecified CAT scan revealed abscess. Patient was subsequently admitted for 8 days and received IV antibiotics. No other information surrounding the event was reported. The concurrent medical condition of diverticulitis remain confounder for the event. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.