Life-threatening cardiac tamponade following COVID-19 vaccination; 3 recurrences of pericarditis/One was within 48 hours of his COVID-19 booster; Pericardial effusion; This is a literature report for the following literature source(s):   A 75-year-old male patient received BNT162b2, BNT162b2 omi ba.4-5 (BNT162B2, BNT162B2 OMI BA.4-5), as dose 3 (booster), single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "rheumatoid arthritis" (ongoing); "Pericardiocentesis" (unspecified if ongoing), notes: removed 275 ml of exudative effusion with 14,140 nucleated cells/mL; "cardiac tamponade" (ongoing). The patient's concomitant medications were not reported. Vaccination history included: Bnt162b2 (DOSE 1, SINGLE), for COVID-19 immunisation; Covid-19 vaccine (DOSE 2, SINGLE (UNKNOWN MANUFACTURER)), for covid-19 immunisation. The following information was reported: CARDIAC TAMPONADE (hospitalization, medically significant, life threatening), outcome "unknown", described as "Life-threatening cardiac tamponade following COVID-19 vaccination"; PERICARDITIS (hospitalization, medically significant), 48 hrs after the suspect product(s) administration, outcome "unknown", described as "3 recurrences of pericarditis/One was within 48 hours of his COVID-19 booster"; PERICARDIAL EFFUSION (hospitalization, medically significant), outcome "unknown". The patient underwent the following laboratory tests and procedures: Bacterial test: negative; Cytology: was inconsistent with malignancy; Cytomegalovirus test: no; Epstein-Barr virus test: no; Fungal test: negative; Nasopharyngeal swab: negative, notes: for SARS-CoV-2; SARS-CoV-2 test: negative. Therapeutic measures were taken as a result of cardiac tamponade, pericarditis, pericardial effusion.  Background: The author present two cases of life-threatening cardiac tamponade following COVID-19 vaccination. Methods: Two cases of cardiac tamponade in temporal association with COVID-19 vaccination were reviewed. Case 1: was 75-year-old male with rheumatoid arthritis admit with chest pressure and hypotension 2 days after his 1st dose of Pfizer-Biontech COVID-19 vaccine. Pericardiocentesis removed 275ml of exudative effusion with 14,140 nucleated cells/ml. Fluid bacterial and fungal cultured were negative; cytology was inconsistent with malignancy. He had no Epstein-Barr Virus (EBV) or cytomegalovirus (CMV) viremia. Symptoms resolved on prednisone and colchicine. A week later, he had an uneventful second COVID-19 vaccine. He went on to have 3 recurrences of pericarditis starting two months after his first. One within 48 hrs of his COVID-19 booster. He was on long term prednisone. Conclusion: Given the proximity to COVID-19 vaccination and lack of alternative explanations, the author believe that tamponade was a direct result of post-vaccine inflammatory pericarditis. Neither patient had a prior history of pericardial effusion. Both tested negative for SARS-CoV-2 by nasopharyngeal swab excluding active infection. Healthcare providers should consider the possibility of pericardial effusion and tamponade in patients with chest pain, shortness of breath, or hypotension following COVID-19 vaccination.; Sender's Comments: There is a reasonable possibility that the event pericarditis was related to BNT162b2, BNT162B2 OMI BA.4-5 based on known drug safety profile and close temporal relationship. Based on the temporal relationship, the association between the events cardiac tamponade and pericardial effusion with BNT162b2, BNT162B2 OMI BA.4-5 can not be fully excluded.  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.,Linked Report(s) : US-PFIZER INC-PV202300012321 Same article/drug and different patient/event;US-PFIZER INC-202300029169 Same article/drug and different patient/event;