Acute Perimyocarditis; The initial case was missing the following minimum criteria: [Unspecified product]. Upon receipt of follow-up information on [26Dec2022], this case now contains all required information to be considered valid.  This is a literature report for the following literature source:  A 19-year-old male patient received COVID-19 Vaccine - Manufacturer Unknown, as dose 3 (booster), single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "emergency room" (unspecified if ongoing). The patient's family history included: "Ehlers-Danlos syndrome" (unspecified if ongoing), notes: in mother. Concomitant medication(s) included: HEPARIN taken for acute coronary syndrome; METOPROLOL TARTRATE oral. Past drug history included: Ibuprofen, reaction(s): "Anaphylaxis". Vaccination history included: Bnt162b2 (DOSE 1, SINGLE); Bnt162b2 (DOSE 2, SINGLE). The following information was reported: MYOPERICARDITIS (hospitalization, medically significant, life threatening), 2 weeks after the suspect product(s) administration, outcome "recovered", described as "Acute Perimyocarditis". The patient underwent the following laboratory tests and procedures: Adenovirus test: Negative; Angiogram: motion artifact because of tachycardia, notes: Short segment of the right coronary artery, the distal circumflex, and the branch vessels such as the posterior descending artery could not be satisfactorily evaluated on CCTA but for the most part, the epicardial coronary arteries were widely patent without definite sites of stenosis; Antibody test: Negative; Blood thyroid stimulating hormone: within normal range; Chest X-ray: no acute pathology, notes: a normal sized mediastinum; Computerised tomogram thorax: no  aortic aneurysm or dissection.; Coxsackie virus test: Negative; C-reactive protein: 1.6 mg/l; Cytomegalovirus test: Negative; Echocardiogram: preserved EF, notes: no wall motion abnormalities; ejection fraction  60%, notes: no wall motion abnormalities, or valvular abnormalities, and no pericardial effusion was noticed; showed a normal EF, notes: one-month post-discharge; Ejection fraction: normal, notes: one-month post-discharge; Ejection fraction: 60 %; 44 %; Electrocardiogram: sinus tachycardia,, notes: right axis deviation incomplete right bundle branch block, with some premature ventricular contractions; sinus tachycardia, notes: old EKG from two years ago only; ST segment elevations, notes: in leads V4, V5, V6, II, III, and aVF; Epstein-Barr virus test: Negative; Heart rate: 120 bpm, notes: tachycardia; rare PVCs and sinus tachycardia, notes: by telemetry; Hepatitis A virus test: Negative; Hepatitis B virus test: Negative; Hepatitis C virus test: Negative; HIV test: Negative; Influenza virus test: Negative; Magnetic resonance imaging heart: edema in posterolateral wall, notes: of mild left ventricular (LV) dysfunction with an EF of 44%, a diffuse delayed enhancement of the LV myocardium in a sub epicardial distribution, with sparing of the basal segments, consistent with myocarditis; Physical exam: anxious appearance, notes: mild tenderness over the sternum, and hypermobility of joints (particularly fingers); Red blood cell sedimentation rate: 2 mm/hr; SARS-CoV-2 test: negative; Troponin T: 700 ng/L, notes: elevated; 635 ng/L; 2862 ng/L, notes: elevated; Urine analysis: negative; Viral test: Negative; Negative. Therapeutic measures were taken as a result of myopericarditis.  Author's conclusion This case highlights perimyocarditls as a rare complication of mRNA COVID-19 vaccine booster. The long term sequelae of this vaccine-induced myocarditis and pericarditis remain unclear and further  studies are needed. Considering the protective effects of the COVID-19vaccine against hospitalization and death, an the low incidence of vaccine-associated myocarditis, the overall  benefits of the COVID-19 vaccine would outweigh the risks. However, It Is unclear Ifthe same rate of benefit Is provided by thebooster doses ofth COVID-19vaccine. Thus, the decision for booster doses should be individualized based on the risks versus benefits.; Sender's Comments: As there is limited information in the case provided, the causal association between the Reported event Myopericarditis and the suspect drug cannot be excluded. The case will be reassessed once new information is available. The impact of this report on the benefit/risk profile of the Pfizer drug is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics Committees, and Investigators, as appropriate.