IL6 and COVID-19: However, high IL-6 level in saliva (≥ 150 pg mL−1) of these patients was not predictor for worse clinical outcomes of COVID-19, after adjusting for the above-mentioned patients’ factors and COVID-19 severity markers (Fig. 4B, P = 0.740, and Fig. 4D, P = 0.457; Supplementary Table 4).