Since previous pharmacokinetic results with male rats on the safety of mRNA encoding human-erythropoietin and complexed with lipid nanoparticles reported a more prolonged thromboplastin and prothrombin time in treated animals (66), it is possible that spike-induced erythrocyte agglutination and platelet activation may further contribute to increased thromboembolic event risk calculated for the mRNA COVID-19 vaccines. This evidence concerns the gene F3 and COVID-19.