Systemic inflammation is typically characterized by elevations in the levels of APPs, including CRP, a-2M, haptoglobin, and serum amyloid P. Recent studies have reported that there is a higher concentration of inflammatory markers such as CRP in patients with severe or moderate SARS-CoV-2 infection and during the longitudinal follow-up levels of CRP steadily declined within 10 days after admission in moderate and severe cases, indicating that CRP can be used as the potent inflammatory biomarker (29). Here, HP is linked to inflammatory response.