HAMP and COVID-19: Hepcidin concentrations were significantly increased in patients with mild and moderate [44.25 (23.49–54.97) ng/mL], severe [75.95 (54.40–90.91) ng/mL], and critical [85.79 (63.18–94.38) ng/mL] disease course compared to healthy subjects (p < 0.001) and were higher in severe and critical patients compared with patients in mild and moderate COVID-19 groups (Figure 2a).