LEPR and type 2 diabetes mellitus: The effect of T2DM on SARS-CoV-2 infection was evaluated by intranasal inoculation of 12-week-old male Lepr-deficient, T2DM (BKS db/db), and 12-week-old male wildtype control (BKS +/+, lean) mice as described above, and monitored up to 21 dpi (Figure 1A).