As expected, we found that IL-17 mRNA level in whole blood (Fig 1A, close to 1.5 log fold-change (FC) increase of IL-17 mRNA; P<0.001), and protein level in plasma were significantly elevated in severe COVID-19 cases compared to mild/moderate or asymptomatic COVID-19 cases (Fig 1B, mean 63.4 pg.ml-1 in severe vs 28.8 pg.ml-1 in mild/moderate COVID-19 cases; P<0.001). This evidence concerns the gene IL17A and COVID-19.