“It is concluded that ACE2+ endothelial damage is a central part of SARS-CoV2 pathology and may be induced by the spike protein alone… In sum, the data presented indicates that the full-length S1 subunit of the spike protein of SARS-CoV-2 alone is capable, without the infectious virus, of inducing systemic microendothelial cell damage in mice with a cognate pattern of complement activation and increased cytokine expression and the concomitant thromboses/hypercoagulable state. This disease pattern strongly parallels the extra-pulmonary manifestations of severe human COVID-19 and suggests that the latter may not represent systemic infectious virus. Thus, prevention of the CNS disease so common in severe COVID-19 may require neutralization/removal of the circulating pseudovirions.”

Nuovo, G.J., Magro, C., Shaffer, T. et al. “Endothelial Cell Damage Is the Central Part of COVID-19 and a Mouse Model Induced by Injection of the S1 Subunit of the Spike Protein.” Annals of Diagnostic Pathology 51 (April 2021): 151682. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7758180/