"Introduction
... Here, we explore cardiovascular side effects following COVID-19 inoculation, including myocarditis/pericarditis, and thrombotic events in addition to rare cases of arrhythmia, hypertension, acute coronary syndrome, and cardiac arrest...
Cardiovascular complications of COVID-19 vaccines
Myocarditis and pericarditis: Among reported adverse reactions, myocarditis/pericarditis is the most frequently reported cardiovascular comorbidity for mRNA vaccines, especially following the second vaccination. The disease ranges from mild asymptomatic inflammation of the heart to severe heart failure and even death. A total of 2984 incidences of myocarditis and 2081 cases of pericarditis were reported in the Vaccine Adverse Event System (VAERS)... The age of individuals who experienced postvaccination myocarditis ranged from 14 to 67, with 79% cases being those who under 30 years. Furthermore, the majority of patients were male (65.1%)...
The pathophysiology underneath cardiac sequelae of COVID-19 vaccine remains undefined. As shown in Figure 2, a nonspecific inflammatory response from exposure to the nucleotide sequence and cross-reactivity of antibodies has been speculated due to molecular mimicry between SARS-CoV-2-encoded S protein and similar human protein sequences, such as α-myosin vital in myocardial contraction. In addition, antibodies against self-antigens reported in myocarditis patients (e.g., antiproteolipid protein 1, antiendothelial antigen, or antiaquaporin 4) were detected in patients with vaccine-induced myocarditis, supporting the presence of a myocarditis mechanism mediated by autoantibodies generation. Moreover, although nucleoside modifications of mRNA lowered their innate immunogenicity, the immune response to mRNA may still be aberrant in individuals with genetic susceptibility. In these individuals, the immune system may detect mRNA in the vaccine as an antigen, leading to immunologic and proinflammatory cascades to favor the development of myocarditis...
Thrombosis and thrombocytopenia: COVID-19 vaccines, especially in the adenoviral platform, have been associated with the development of thrombotic thrombocytopenia. VAERS reported 5052 undefined thrombosis, 4144 pulmonary embolisms, 3001 deep veinous thromboses, 1195 thrombocytopenias, and 233 cerebral venous sinus thromboses among 604 million doses of SARS-CoV-2 vaccines in the United States...
The antibodies against PF4 [platelet factor 4] are produced as part of the immune stimulation and inflammatory reaction induced by vaccination, which activates massive platelets and facilitates clotting; although, thromboxane A2 (TxA2) and COX-2 genes may also be involved. It is believed that the generation of S protein by COVID-19 vaccination prompts the generation of TxA2 and COX-2 in megakaryocytes. TxA2 stimulates the COX-2 expressing platelets, contributing to platelet activation and aggregation and ultimately, thrombotic inflammation. Also, following intravenous injection, double-stranded DNA borne by the adenoviral vector-based COVID-19 vaccine may inadvertently interact with platelets because of microtrauma and microbleeding at the injection site. Moreover, the ethylenediaminetetraacetic acid content in vaccine preparations increases vascular permeability at the injection site, resulting in the rapid spread of vaccine components into the bloodstream. Platelet activation and aggregation in turn contribute to the release of cytokines, binding of platelets to endothelial cells, and consequently, activation of endothelial cells by higher vascular cell adhesion molecule-1 levels. Interactions between endothelial cells and platelets then facilitate platelet aggregation and thrombogenesis...
Conclusions and precautions for vaccine usage
Accumulating evidence documents a number of cardiovascular comorbidities, including myocarditis/pericarditis, thrombosis and thrombocytopenia, acute coronary syndrome, hypertension, arrhythmia, Takotsubo cardiomyopathy, cardiac arrest, and death in individuals receiving COVID-19 vaccines."
© 2022 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)