Autopsy-based histopathological characterization of myocarditis after anti-SARS-CoV-2-vaccination

Abstract

Cases of myocarditis, diagnosed clinically by laboratory tests and imaging have been described in the context of mRNA-based anti-SARS-CoV-2 vaccination. Autopsy-based description of detailed histological features of vaccine-induced myocarditis is lacking. We describe the autopsy findings and common characteristics of myocarditis in untreated persons who received anti-SARS-CoV-2 vaccination. Standardized autopsies were performed on 25 persons who had died unexpectedly and within 20 days after anti-SARS-CoV-2 vaccination. In four patients who received a mRNA vaccination, we identified acute (epi-)myocarditis without detection of another significant disease or health constellation that may have caused an unexpected death. Histology showed patchy interstitial myocardial T-lymphocytic infiltration, predominantly of the CD4 positive subset, associated with mild myocyte damage. Overall, autopsy findings indicated death due to acute arrhythmogenic cardiac failure. Thus, myocarditis can be a potentially lethal complication following mRNA-based anti-SARS-CoV-2 vaccination. Our findings may aid in adequately diagnosing unclear cases after vaccination and in establishing a timely diagnosis in vivo, thus, providing the framework for adequate monitoring and early treatment of severe clinical cases.

Keywords: Autopsy; Cardiac pathology; Myocarditis; SARS; Vaccination.

Fig. 1

A Lymphocytic aggregates in the interventricular septum of case 1 with associated myocardiocyte destruction. B The infiltrate is predominantly composed of CD3-positive T-lymphocytes and C CD68-positive macrophages. D In lower magnification two foci of CD4-positive lymphocytes are evident (D)

Fig. 2

A Inflammatory focus in the left ventricular wall of case 2. B The infiltrate is predominantly composed of CD68-positive macrophages and C CD3-positive T-lymphocytes with (D) co-expression of CD4

Fig. 3

A The jab site in the deltoid muscle reveals focal inflammation. The composition is similar to the phenotype of the myocardial infiltrates showing predominantly, B CD3 and C CD4-coexpressing lymphocytes and D interspersed CD68-positive macrophages