Myopericarditis; fever; chills; myalgia; This literature-non-study case was reported in a literature article and describes the occurrence of MYOCARDITIS (Myopericarditis) in a 22-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.       Family history included Autoimmune disorder (Patient endorsed a family history of autoimmune disorders (her mother has autoimmune thyroid disease, but she does not recall the exact diagnosis).).    On an unknown date, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced MYOCARDITIS (Myopericarditis) (seriousness criteria hospitalization and medically significant), PYREXIA (fever), CHILLS (chills) and MYALGIA (myalgia). The patient was treated with COLCHICINE for Myopericarditis, at a dose of 0.6 milligram and IBUPROFEN for Adverse event, at a dose of 600 milligram. At the time of the report, MYOCARDITIS (Myopericarditis), PYREXIA (fever), CHILLS (chills) and MYALGIA (myalgia) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Angiogram: abnormal (abnormal) showed a trace left pleural effusion and opacities of lung bases suggestive of atelectasis without acute pulmonary embolism.. On an unknown date, Antinuclear antibody positive: positive positive with 1:1280 titer, and a speckled pattern and antiSjogren's-syndrome-related antigen A autoantibodies were also positive.. On an unknown date, Body temperature: 38.8 degree c 38.8 degree C. On an unknown date, C-reactive protein: 129.1 mg/l 129.1 mg/L. On an unknown date, Echocardiogram: abnormal showed a left ventricular ejection fraction of 6065% and trace tricuspid regurgitation. No pericardial effusion or other acute findings were noted.. On an unknown date, Electrocardiogram: abnormal (abnormal) showed sinus tachycardia with borderline right axis deviation and non-specific T wave abnormalities in inferior leads without PR or ST-segment changes.. On an unknown date, Fibrin D dimer: 6.30 µg/ml 6.30 µg/mL. On an unknown date, Heart rate: 127 beats/min 127 beats/min. On an unknown date, Magnetic resonance imaging heart: abnormal (abnormal) cMRI with gadolinium enhancement was performed to diagnose myopericarditis. cMRI showed a mildly reduced left ventricular ejection fraction of 48% with mild global hypokinesis.. On an unknown date, Red blood cell sedimentation rate (0-22): 50 mm/hr 50 mm/hr. On an unknown date, Troponin I (0-0.028): 0.164 ng/ml elevated at 0.164 ng/mL and was trended to a peak of 3.897 ng/ mL 10 h after admission, with a subsequent downtrend to 3.186 ng/mL 15 h after admission..     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered MYOCARDITIS (Myopericarditis), PYREXIA (fever), CHILLS (chills) and MYALGIA (myalgia) to be possibly related.    There was diffuse circumferential hyperenhancement of the pericardium suggestive of acute pericarditis. On T2-weighted short tau inversion recovery images, hyperenhancement of the apical septal walls was noted as suggestive of myocardial edema.  A diagnosis of acute myopericarditis was made, prompting initiation of colchicine 0.6 mg daily (for three months) and 600 mg ibuprofen three times daily (for two weeks). She reported improvement in chest pain, followed by resolution by the time of a two-week outpatient follow-up visit.  Although the patient did not undergo myocardial biopsy, clinical presentation, laboratory results, and MRI findings are suggestive of probable post-COVID vaccine myopericarditis triggered by an underlying, subclinical predisposition for autoimmunity.  Concomitant product use was not provided by the reporter.  Company Comment: This case concerns a 22 year-old, female with Family history of Autoimmune disorders, who experienced the expected serious event of myocarditis. The event occurred approximately 1 days after the second dose of mRNA-1273 Moderna vaccine.  Lab data reported: Troponin I: elevated at 0.164 ng/mL, peak of 3.897 ng/ mL 10 h after admission, with a subsequent downtrend to 3.186 ng/ml;  cMRI showed a mildly reduced left ventricular ejection fraction of 48% with mild global hypokinesis; Electrocardiogram: showed sinus tachycardia with borderline right axis deviation and non-specific T wave abnormalities in inferior leads without PR or ST-segment changes; Echocardiogram: showed a left ventricular ejection fraction of 6065% and trace tricuspid regurgitation The rechallenge is N/A (no more doses are expected)  The benefit-risk relationship of mRNA-1273 Moderna vaccine in not affected by this report. Family history of autoinmune disorders could be a potentially risk factor.   Most recent FOLLOW-UP information incorporated above includes: On 13-Oct-2021: Follow up received by safety 13-Oct-2021 has Email and contain new information. Updated patient details, medical history, family history, and lab data in patient tab. Added additional events in events tab and treatment drugs in product tab.; Sender's Comments: This case concerns a 22 year-old, female with Family history of Autoimmune disorders, who experienced the expected serious event of myocarditis. The event occurred approximately 1 days after the second dose of mRNA-1273 Moderna vaccine.  Lab data reported: Troponin I: elevated at 0.164 ng/mL, peak of 3.897 ng/ mL 10 h after admission, with a subsequent downtrend to 3.186 ng/ml;  cMRI showed a mildly reduced left ventricular ejection fraction of 48% with mild global hypokinesis; Electrocardiogram: showed sinus tachycardia with borderline right axis deviation and non-specific T wave abnormalities in inferior leads without PR or ST-segment changes; Echocardiogram: showed a left ventricular ejection fraction of 6065% and trace tricuspid regurgitation The rechallenge is N/A (no more doses are expected)  The benefit-risk relationship of mRNA-1273 Moderna vaccine in not affected by this report. Family history of autoinmune disorders could be a potentially risk factor.