Based on an integrative analysis of a genome-wide CRISPR dropout screen and a genome-wide association study analysis between variants of identified host factors and clinical features, Hou et al. identified KLF5 as a significant anti-viral factor, with genetic variations linked to COVID-19 hospitalization and severe symptoms, as well as a downregulation of KLF5 mRNA expression in severe COVID-19 cases compared to mild cases, thereby highlighting its clinical relevance in the disease.59 This evidence concerns the gene KLF5 and COVID-19.