Myocarditis; This literature-non-study case was reported in a literature article and describes the occurrence of MYOCARDITIS (Myocarditis) in a 34-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis.   LITERATURE REFERENCE:    No Medical History information was reported.   On an unknown date, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced MYOCARDITIS (Myocarditis) (seriousness criterion hospitalization). The patient was hospitalized for 2 days due to MYOCARDITIS. At the time of the report, MYOCARDITIS (Myocarditis) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Atrial pressure: 3 mmHg. On an unknown date, Biopsy heart: No significant abnormality. On an unknown date, Blood creatinine: 1.10 mg/dl. On an unknown date, Blood pressure systolic: 144 mmHg. On an unknown date, Body mass index: 30.4. On an unknown date, Body surface area: 2.3 square metre. On an unknown date, C-reactive protein (0.0-10.0 milligram per litre): 56.2 milligram per litre peak. On an unknown date, Cardiac index: 3.68 litre per minute per square metre. On an unknown date, Echocardiogram: LVEF 56%, no regional WMA (wall-motion abnormality), bicuspid aortic valve, aortic root diameter 4.4 cm. On an unknown date, Ejection fraction: 56 %. On an unknown date, Electrocardiogram: Left anterior fascicular block, late R wave progression. On an unknown date, Fibrin D dimer (Unknown-500 ng/mL): 560 ng/mL. On an unknown date, Haemoglobin: 16.6 g/dL. On an unknown date, Heart rate: 96 96 bpm. On an unknown date, Magnetic resonance imaging heart: Focal LGE (late gadolinium enhancement) of the basal inferolateral wall and proximal anterior septum, normal LV and RV size and function. On an unknown date, Microscopy: Normal myofibrillary organization, some interstitial cell debris. Some mitochondrial proliferation of golgi, overall reading is "mildly abnormal". On an unknown date, Platelet count (150-400 microliter): 215 microliter. On an unknown date, Platelet factor 4: Negative. On an unknown date, Prothrombin time (11.1-13.7 secs): 12.4 secs. On an unknown date, Pulmonary arterial pressure: 16 mmHg. On an unknown date, Pulmonary arterial wedge pressure: 7 mmHg. On an unknown date, Red blood cell sedimentation rate (0-10 mm/hr): 16 mm/hr. On an unknown date, SARS-CoV-2 RNA: Negative. On an unknown date, SARS-CoV-2 test: (Negative) all 4 genomic regions. On an unknown date, Troponin I: 3.44 ng/mL. On an unknown date, White blood cell count: 9.0 10^9/L.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered MYOCARDITIS (Myocarditis) to be related.    Concomitant and treatment medications were not reported.  Patient presented with symptoms of substernal chest pain radiating to left arm.   No arrhythmias during hospitalization was reported.  Patient underwent endomyocardial biopsy (EmBx) for histopathology and gene expression performed at 29 days after onset of chest pain or other cardiac symptoms and 32 days after vaccination.  Hemodynamic support and corticosteroids was reported as none.  Patient had gene expression measured had mRNA abundance values similar to the COVID-19 data. The similarity was striking, and none of the individual gene mRNA abundances had P values less than 0.10 (range 0.12-0.44) between the COVID-19 and post-vaccination groups.  Author investigated 7 COVID-19 and 6 post-mRNA vaccination patients with myocardial injury and found nearly identical alterations in gene expression that would predispose to inflammation, coagulopathy, and myocardial dysfunction. In summary, it appears that histopathologic findings in myocardial injury associated with COVID-19 or mRNA vaccine can be due to causes other than myocarditis.  This case belonged to case 4 from table S4.  Company Comment: This literature non study case concerns a 34 year old male patient with concurrent obesity, no previous history of myopericarditis, who experienced the expected, serious (hospitalization) of Myocarditis, 3 days after receiving the third dose with mRNA-1273 vaccine. The patient was admitted to the hospital with substernal chest pain radiating to left arm. His investigations included: Elevated C- reactive protein, Troponin I and D-dimer; Echocardiogram- LVEF 56%, no regional wall-motion abnormality; Electrocardiogram-Left anterior fascicular block, late R wave progression; Magnetic resonance imaging heart-Focal late gadolinium enhancement of the basal inferolateral wall and proximal anterior septum, normal LV and RV size and function; Coronary angiogram was not done; Microscopy-Normal myofibrillary organization, some interstitial cell debris. Some mitochondrial proliferation of golgi, overall reading was "mildly abnormal"; Biopsy heart- No significant abnormality; SARS-CoV-2 myocardial RT-PCR test- negative, all 4 genomic regions. Patient was hospitalized for 2 days for Myocarditis. The patient did not require any hemodynamic or corticosteroid support. No information on detailed clinical course, treatment, outcome of the event and details pertaining to the previous doses was available in the report. The benefit-risk relationship of mRNA-1273 is not affected by this report.   This case was linked to MODERNATX, INC.-MOD-2022-670442, MODERNATX, INC.-MOD-2022-670433, MODERNATX, INC.-MOD-2022-670444, MODERNATX, INC.-MOD-2022-668401 (E2B Linked Report).; Sender's Comments: This literature non study case concerns a 34 year old male patient with concurrent obesity, no previous history of myopericarditis, who experienced the expected, serious (hospitalization) of Myocarditis, 3 days after receiving the third dose with mRNA-1273 vaccine. The patient was admitted to the hospital with substernal chest pain radiating to left arm. His investigations included: Elevated C- reactive protein, Troponin I and D-dimer; Echocardiogram- LVEF 56%, no regional wall-motion abnormality; Electrocardiogram-Left anterior fascicular block, late R wave progression; Magnetic resonance imaging heart-Focal late gadolinium enhancement of the basal inferolateral wall and proximal anterior septum, normal LV and RV size and function; Coronary angiogram was not done; Microscopy-Normal myofibrillary organization, some interstitial cell debris. Some mitochondrial proliferation of golgi, overall reading was "mildly abnormal"; Biopsy heart- No significant abnormality; SARS-CoV-2 myocardial RT-PCR test- negative, all 4 genomic regions. Patient was hospitalized for 2 days for Myocarditis. The patient did not require any hemodynamic or corticosteroid support. No information on detailed clinical course, treatment, outcome of the event and details pertaining to the previous doses was available in the report. The benefit-risk relationship of mRNA-1273 is not affected by this report. MODERNATX, INC.-MOD-2022-670433:26-YO-Male MODERNATX, INC.-MOD-2022-670444:21-YO-Male MODERNATX, INC.-MOD-2022-670442:55-YO-Female MODERNATX, INC.-MOD-2022-668401:23-YO-Female