Myopericarditis with hemorrhagic pericardial effusion following BNT162b2 mRNA COVID-19 vaccine.

Since the onset of the COVID-19 pandemic, to date, around 385 million cases have been diagnosed worldwide leading to an estimated 5.7 million death toll. Mass vaccination campaigns have been conducted to control the spread of infection with the most commonly used vaccines being Pfizer-BioNTech and Moderna. However, the adverse effects of vaccination have not yet been fully investigated. Of concern are some serious cardiovascular events such as myocarditis, pericarditis, or perimyocarditis development post-vaccination. Hemorrhagic pericardial effusion has not been reported. However, we report a case of myopericarditis with a hemorrhagic pericardial effusion that developed two weeks following BNT162b2 mRNA COVID-19 vaccination. We performed a complete workup identifying the underlying cause that did not yield any significant findings. Our patient was treated with colchicine and ibuprofen, and he made a full recovery. A follow-up cardiovascular magnetic resonance imaging (CMR) showed no signs of active inflammation.