Myocarditis; This literature-non-study case was reported in a literature article and describes the occurrence of MYOCARDITIS (Myocarditis) in a 23-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.   No Medical History information was reported.   On an unknown date, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On an unknown date, received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On an unknown date,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced MYOCARDITIS (Myocarditis) (seriousness criteria hospitalization and medically significant). The patient was hospitalized for 3 days due to MYOCARDITIS. At the time of the report, MYOCARDITIS (Myocarditis) had resolved. Possible    DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, C-reactive protein: 41 mg/l (High) CRP elevation, 11 mg/l (Inconclusive) CRP declined to 11 mg/L by the third day of her hospitalization. and 0.8 mg/l (normal) She presented to clinic for follow-up two weeks after discharge, where her CRP had declined to 0.8 mg/L and she had no residual symptoms. On an unknown date, Coxsackie virus test: negative (Negative) Negative. On an unknown date, Cytomegalovirus test: negative (Negative) Negative. On an unknown date, Echocardiogram: unknown (Inconclusive) Left Ventricular Ejection Fraction (LVEF) 5560%, basal inferior and basal inferolateral hypokinesis. On an unknown date, Electrocardiogram: abnormal (abnormal) Down-sloping PR depressions, diffuse ST elevations. On an unknown date, Epstein-Barr virus test: negative (Negative) Negative. On an unknown date, Hepatitis C virus test: negative (Negative) Negative. On an unknown date, Magnetic resonance imaging heart: cardiac magnetic resonance (Inconclusive) Cardiac Magnetic resonance (CMR) revealed late gadolinium enhancement involving the basal inferior, basal to mid inferolateral, mid anterolateral, apical lateral, apical septal, and apical inferior wall segments in a subepicardial distribution pattern, consistent with myocarditis. On an unknown date, Serology test: negative (Negative) Negative. On an unknown date, Troponin I: 14,045 pg/ml (High) Troponin elevation and 16,263 pg/ml (High) Troponin elevation.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered MYOCARDITIS (Myocarditis) to be possibly related.    No concomitant medication was provided by the reporter.  Her symptoms resolved quickly, and her CRP declined by the third day of her hospitalization. She was discharged on hospital day 3. She presented to clinic for follow-up two  weeks after discharge, and she had no residual symptoms.   No treatment medication information was provided by the reporter  Based on the current available information and temporal association between the use of the product and the start date of the event, a causal relationship cannot be excluded.   This case was linked to MOD-2021-293732, MOD-2021-293733 (Patient Link).; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the event, a causal relationship cannot be excluded.