MPO and COVID-19: NET production, whether assessed by a measurement of circulating markers (e.g., MPO-DNA complexes) or ex vivo generation, is significantly increased in obese subjects and individuals with T2D (91–93), patient groups that are not only at high risk of developing severe COVID-19 (102, 103) but who experienced poor outcomes in the 2009 H1N1 influenza A virus pandemic (104).