Acute pericarditis; This is a literature report.  A 18 year-old male patient received bnt162b2 (BNT162B2) (Batch/Lot number: unknown) as dose 1, single for covid-19 immunisation. The patient's relevant medical history and concomitant medications were not reported. The following information was reported: PERICARDITIS (hospitalization, medically significant), outcome "unknown", described as "Acute pericarditis". The event "acute pericarditis" was evaluated at the emergency room visit. The patient underwent the following laboratory tests and procedures: blood pressure measurement: normal; body temperature: 37.94 Centigrade; 37.83 Centigrade, notes: 10 days later; chest x-ray: normal limits; enlarged cardiac silhouette; echocardiogram: normal limits; large pericardial effusion with evidence, notes: of early tamponade, including a dilated inferior venacava and right atrial diastolic collapse; electrocardiogram: acute pericarditis, notes: diffuse ST elevations and PR depressions; diffuse st elevations; heart rate: 111 beats per minute; 120 beats per minute; laboratory test: 31 breaths per minute; physical examination: unremarkable, notes: other than regular tachycardia; troponin: normal, notes: Normal within limits. Therapeutic measures were taken as a result of pericarditis included ibuprofen 800 mg every 8 hours, with a plan to follow-up with Cardiology as an outpatient. Three days later, his chest pain was persistent and he was started on additional colchicine 0.6 mg daily. The cardiac intensive care unit and underwent emergent pericardiocentesis with removal of approximately 600 mL of serosanguinous fluid. Pericardial fluid studies were consistent with an exudative process. The patient was discharged 4 days later on indomethacin 25 mg every 6 hours and colchicine 0.6 mg every 12 hours. He was readmitted to the hospital 1 week later for persistent tachycardia and recurrent pericardial effusion, which improved after intravenous ketorolac and intravenous methylprednisolone. He was ultimately discharged on prednisone 40 mg daily, celecoxib 200 mg every 12 hours, and a plan to start rilonacept, an interleukin-1 inhibitor recently approved for the treatment of recurrent pericarditis.  Clinical course: A previously healthy 18-year-old man presented with a chief complaint of fever, pleuritic chest pain, and short- ness of breath 3 weeks after receiving the first dose of the Pfizer-BioNTech COVID-19 vaccine. On arrival to the Emergency Department (ED), vital signs were remarkable for a temperature of 37.94 °C (100.3 °F) and heart rate of 111 beats/min. Chest x-ray study, formal echocardiogram, and troponins were all within normal limits. After discussion with the Cardiologisr, he was discharged on a regimen of ibuprofen 800 mg every 8 h, with a plan to follow-up with Cardiology as an outpatient. Three days later, his chest pain was persistent, and he was started on additional colchicine 0.6 mg daily. Approximately 10 days later, the patient returned to the ED with ongoing fever, pleuritic chest pain, shortness of breath, and dizziness. Vital signs were remarkable for an elevated temperature to 37.83 °C (100.1 °F), tachycardia to 120 beats/min, and tachypnea to 31 breaths/min. Blood pressure was normal. ECG demonstrated persistent diffuse ST elevations. Chest x-ray study now showed an enlarged cardiac silhouette. Echocardiogram demonstrated a large pericardial effusion with evidence of early tamponade, including a dilated inferior vena cava and right atrial diastolic collapse.  No follow-up attempts are possible; information about lot/batch number cannot be obtained. No further information is expected.; Sender's Comments: Based on known drug safety profile, there is reasonable possibility of causal association between the event  pericarditis the suspect drug BNT162B2. The impact of this report on the benefit/risk profile of the Pfizer product 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.