Validation of HO-1 expression levels in larger COVID-19 patient cohorts is therefore necessary to confirm the potential use of HO-1 as a prognostic tool for COVID-19 management and to compare its performance with other established parameters used for COVID-19 disease progression, such as C-reactive protein (CRP) and the neutrophil to lymphocyte ratio (NLR). This evidence concerns the gene CRP and COVID-19.