C5 and COVID-19: Even in this expanded cohort, plasma C5a levels remained significantly higher in hospitalized patients with COVID-19 requiring ICU admission [456.9 (269.2 – 1,282) pg/mL, N=40] versus those who did not [243.9 (193.3 – 280.3) pg/mL, N=9, p=0.0027, Fig. 2E].