CTSL and COVID-19: In GeneCards database, we obtained 324 COVID-19 related genes with relevance scores higher than zero, and among which 20 targets that scored higher than 2 were considered as essential COVID-19 targets, namely angiotensin-converting enzyme II (ACE2), dipeptidyl-peptidase 4, interleukin 2 receptor, alpha, cathepsin L, interleukin 6 (IL6), interleukin 10 (IL10), angiotensin-converting enzyme (ACE), vascular endothelial growth factor A (VEGFA).