Acute myocarditis; Sharp resteosternal chest pain that radiated to her L jaw and woke her from sleep for which she presented to an outside hospital; lightheadedness; unable to complete her usual exercise routine; This literature-non-study case was reported in a literature article and describes the occurrence of MYOCARDITIS (Acute myocarditis) and CHEST PAIN (Sharp resteosternal chest pain that radiated to her L jaw and woke her from sleep for which she presented to an outside hospital) in a 21-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.   LITERATURE REFERENCE: Acute myocarditis after a second dose of the mRNA COVID-19 vaccine: a report of two cases. Clinical Imaging. 2021;78:247-49     The patient's past medical history included Electrocardiogram (normal), Stress test (normal) and Genetic polymorphism (4 years prior, normal). Family history included Long QT syndrome (in three of her siblings and her mother).   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) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced MYOCARDITIS (Acute myocarditis) (seriousness criteria hospitalization prolonged and medically significant), CHEST PAIN (Sharp resteosternal chest pain that radiated to her L jaw and woke her from sleep for which she presented to an outside hospital) (seriousness criterion hospitalization), DIZZINESS (lightheadedness) and EXERCISE TOLERANCE DECREASED (unable to complete her usual exercise routine). The patient was hospitalized from sometime in 2021 to sometime in 2021 due to MYOCARDITIS, and then for 2 days due to CHEST PAIN. The patient was treated with METOPROLOL for Adverse event, at an unspecified dose and frequency. At the time of the report, MYOCARDITIS (Acute myocarditis) had resolved and CHEST PAIN (Sharp resteosternal chest pain that radiated to her L jaw and woke her from sleep for which she presented to an outside hospital), DIZZINESS (lightheadedness) and EXERCISE TOLERANCE DECREASED (unable to complete her usual exercise routine) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In 2021, C-reactive protein (Unknown-10 ng/ml): normal (normal) 8 ng/ml. In 2021, Computerised tomogram thorax: negative (Negative) done to exclude pulmonary embolism-negative. Coronary arteries appeared normal with no abnormal course or origin. In 2021, Echocardiogram: abnormal (abnormal) mildly reduced LVEF of 50% with no wall motion abnormalities or significant valvular disease. In 2021, Electrocardiogram: abnormal (abnormal) diffuse, mild concave ST elevations and PR depressions without reciprocal changes. In 2021, Electrocardiogram QT interval: normal (normal) 384 ms and normal (normal) 428 ms. In 2021, Fibrin D dimer (Unknown-500 ng/ml): elevated (High) 640 ng/ml. In 2021, Magnetic resonance imaging: abnormal (abnormal) subepicardial enhancement in the inferolateral wall at the base, elevated values of 1200 ms for T1, as opposed to 950-980 for septal wall and 59-63 ms for T2 as opposed to 44-48 ms for the septal wall, elevated values in the inferolateral wall as compared to the interventricular septum. Normal left ventricular size and function.. In 2021, Red blood cell sedimentation rate (1 mm/h-20 mm/h): normal (normal) 7 mm/h. In 2021, Respiratory viral panel: negative (Negative) negative. In 2021, SARS-CoV-2 test: negative (Negative) negative. In 2021, Troponin (Unknown-0.3 ng/ml): elevated (High) 4.4 ng/ml, elevated (High) elevated troponin I of 2.3 ng/ml and elevated (High) declined to 1.3 ng/ml. In 2021, Vital signs measurement: normal (normal) normal (temperature=36.5, blood pressure=110/70, heart rate=70 bpm, respiratory rate of 18 and oxygen saturation of 99%.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered MYOCARDITIS (Acute myocarditis) to be possibly related. No further causality assessments were provided for CHEST PAIN (Sharp resteosternal chest pain that radiated to her L jaw and woke her from sleep for which she presented to an outside hospital), DIZZINESS (lightheadedness) and EXERCISE TOLERANCE DECREASED (unable to complete her usual exercise routine).    Concomitant medication not provided.  Company comment: Based on the current available information and temporal association between the use of the product, and the start date of the events, a causal relationship cannot be excluded.   This case was linked to MOD-2021-241348 (Patient Link).   Most recent FOLLOW-UP information incorporated above includes: On 29-Jun-2021: Follow up received by safety 30-Jun-2021 included a full text article received.; Sender's Comments: Based on the current available information and temporal association between the use of the product, and the start date of the events, a causal relationship cannot be excluded.