We found that the plasma levels of the 3 NET markers were higher in non-survivor COVID-19 patients than those in survivors [respectively, cell-free total DNA concentration: 437 ng/ml (362–600) vs. 264 ng/ml (200–382), p < 0.0001; MPO–DNA: 3.60 ST (1.65–5.85) vs. 1.20 ST (0.68–2.52), p < 0.001; and H3Cit OD: 0.91 (0.33–1.43) vs. 0.30 (0.14–0.85), p < 0.01] (Figures 3A–C). This evidence concerns the gene MPO and COVID-19.