We addressed the age-dependent effects of SARS-CoV-2 infection on pneumonia severity using Nr4a3-Tocky mice, which were categorized into aged (30–39 weeks old) and adult (15–17 weeks old) groups (G1 aged infected, G2 aged control, G3 adult infected, G4 adult control, Fig 1A). Here, NR4A3 is linked to susceptibility to pneumonia measurement.