Although the serum IL-6 levels of all COVID-19 patients increased compared to normal serum IL-6 levels (7 pg/mL), patients with OD had significantly lower IL-6 levels (16.72 ± 14.28 pg/mL) than patients without OD (60.95 ± 89.33 pg/mL) (p = 0.026) (124). Here, IL6 is linked to COVID-19.