STAT1 and COVID-19: Furthermore, an increase in RIG-1/MDA-5 signaling pathway, measured by mRNA and/or protein levels of RIG-1, MDA-5, and p-IRF3 (Fig. 3D–J, around 2 FC increase of RIG-1, MDA-5, and IRF3 mRNA levels, P < 0.0001), and higher activity of JAK-STAT pathway, measured by levels of p-STAT1, p-STAT2, and p-JAK1 was observed in saliva of VitD treated compared to untreated COVID-19 patients (Fig. 3K–P, P = 0.001; Supplementary Fig. S3).