Hypersensitivity Myocarditis after COVID-19 mRNA Vaccination

Abstract

Background: Myocarditis, even in a severe and lethal form, may occur after COVID-19 mRNA (BNT162b2) vaccination. However, its pathway, morphomolecular characterization and treatment are still unknown. Methods: Routine hematochemical screening, ECG, Holter monitoring, 2D echocardiogram cardiac magnetic resonance (CMR) and invasive cardiac studies (cardiac catheterization, selective coronary angiography, left ventriculography and left ventricular endomyocardial biopsy) are reported from three patients (39F-pt1, 78M-pt2, 52M-pt3) with severe compromise of conduction tissue (junctional rhythm and syncope, pt1) or cardiac function compromise (LVEF ≤ 35%, pt2 and pt3) after COVID-19 mRNA (BNT162b2). Results: Hematochemical data and coronary angiography were normal in the patients studied. Histology showed in all three patients extensive myocardial infiltration of degranulated eosinophils and elevation of serum cationic protein directly responsible for cardiomyocyte damage. These findings demonstrate myocarditis hypersensitivity to some component of the vaccine (spike protein?) acting as a hapten to some macromolecules of cardiomyocytes. Steroid administration (prednisone, 1 mg/kg die for 3 days, followed by 0.33 mg/kg for 4 weeks) was followed by complete recovery of cardiac contractility in pt2 and pt3. Conclusions: Eosinophilic myocarditis is a possible adverse reaction to the mRNA COVID-19 vaccine. Its pathway is mediated by release of cationic protein and responds to short courses of steroid administration.

An autopsy case report of fulminant myocarditis: Following mRNA COVID-19 vaccination

“…Lymphocytic and eosinophilic infiltration were also observed in myocarditis after smallpox vaccination and a mechanism of immune-mediated myocarditis has been speculated [ 9 ]. In addition, Frustaci et al reported three cases of pathohistologically defined eosinophilic myocarditis after COVID19 vaccination, referring to the possibility of eosinophilic myocarditis (hypersensitivity myocarditis) as an allergic reaction and the possibility that immunosuppressive therapy including steroids may be effective [ 10 ]. Considering the response to steroid pulse therapy, it is possible that this mechanism of eosinophil-mediated immunological injury to cardiomyocytes is also involved in this case.…”

Cardiac MRI Findings in COVID‐19 Vaccine‐Related Myocarditis: A Pooled Analysis of 468 Patients

“…A total of 468 patients with suspected myocarditis and cardiac MRI findings were included in this study ( n = 294 from case reports/case series with IPD 5,7,9,11–66,68,70–73,75–87,89,91–95,97–107 and n = 174 from five case series 67,69,74,88,90 with AD). Based on data provided by 100 out of 102 studies, all included patients met CDC criteria for suspected myocarditis.…”

“…Timely diagnosis and management are crucial for improving the prognosis of this complication 5 . An increasing number of studies have utilized cardiac MRI, as the most important noninvasive diagnostic tool, to assess suspected myocarditis associated with COVID‐19 vaccination 5–105 . One narrative review article attempted to address the pattern of myocardial injury following COVID‐19 vaccination based on cardiac MRI findings from 11 case series 4 .…”

Establishing the Pharmacokinetics of Genetic Vaccines is Essential for Maximising their Safety and Efficacy

“…There, the genetic material can become endocytosed and assimilated to express spike protein that will initiate a cascade of localised immunological events [32]. Furthermore, histological observations showed that the rare severe myocarditis observed following mRNA COVID-19 vaccines could be attributed to forming a haptenic link between circulating spike protein and macromolecules of cardiomyocytes membrane [33]. It is worth noting that the presence of free spike protein circulating in the plasma of vaccinated subjects with the mRNA-1273 COVID-19 vaccine has been confirmed recently [34].…”