The distribution of bacterial abundance was tested according to normal, moderately increased, and high levels of the key cytokine IL-6, showing significantly increased abundance of Firmicutes and Enterococcus in COVID-19 patients with high vs. normal IL-6 levels (p = 0.05 and p = 0.02) and between high vs. moderate and normal IL-6 levels (p = 0.04), respectively (Figure 2). The gene discussed is IL6; the disease is COVID-19.