A TF activity assay revealed that three of the eight samples obtained from severe COVID-19 patients clotted during EV pellet isolation and were therefore excluded from the statistical analysis which showed a significant increase in TF activity in the severe group compared to the HCs (t-test, p = 0.0556) and to the mild group (t-test, p = 0.0451) (Figure 4c,d). This evidence concerns the gene TF and COVID-19.