Alternatively, usage of transient depletion systems, such as the Foxp3DTR mouse model [52], would enable targeted elimination of all or some Foxp3+ Tregs prior to infection with SARS-CoV or SARS-CoV-2 in order to directly test the role of Tregs in SARS-CoV virologic and clinical outcomes. This evidence concerns the gene FOXP3 and infection.