Certain blood-based biomarkers, such as lymphocyte, neutrophil and platelet counts, neutrophil-to-monocyte ratio (NMR), neutrophil-to-lymphocyte ratio (NLR), D-dimer, interleukin-6, C-reactive protein (CRP) levels and lactate dehydrogenase (LDH) may discriminate between severe and non-severe COVID-19 (4, 7, 8). Here, CRP is linked to COVID-19.