Recurrent cardiac tamponade following coronavirus disease 2019 mRNA vaccination: A case report.

A 64-year-old woman with a history of subarachnoid hemorrhage, breast cancer, cervical spine tumor, and syringomyelia developed recurrent pericardial effusion and cardiac tamponade after receiving the third dose of coronavirus disease 2019 mRNA vaccine, mRNA-1273 (Spikevax, Moderna). The cardiac tamponade of unknown etiology was intractable with nonsteroidal anti-inflammatory drugs, colchicine, and prednisolone. She underwent thoracoscopic pericardiectomy, and microthrombi were detected in the pericardial tissue. Although the exact causal relationship between vaccination and recurrent cardiac tamponade was unclear, the vaccine possibly caused or triggered the microthrombi formation, resulting in recurrent cardiac tamponade. Because of the potential for cardiovascular side effects such as thrombosis and myocarditis following vaccination, it was deemed necessary to accumulate and analyze such cases.