STAT3 and COVID-19: The clinical symptoms of COVID-19 relate to several cytokines including interleukin (IL)-2, IL-7, IL-10, tumor necrosis factor (TNF) with IL-6, IL-6-signal transducer and activator of transcription 3 (STAT3) and nuclear factor kappa B (NF-κB) pathway being of high significance (Figure 2) [43].