IL6 and COVID-19: At the time of hospital admission, the severe/critical COVID-19 patients had significantly higher levels of IL-6 (median, 11.7 pg/mL, IQR 3.5-49.4 pg/mL) than non-severe COVID-19 patients (2.1 pg/mL, IQR 0.5-12.8 pg/mL, p <0.05, Fig. 3g).