CRP and COVID-19: In both groups, IL-6 was significantly correlated with CRP (COVID-19: ρ = 0.73, p < 0.001; non-COVID-19: ρ = 0.70, p < 0.001) and leucocytes (COVID-19: ρ = 0.39, p < 0.001; non-COVID-19: ρ = 0.57, p < 0.001).