Characteristic Time after disease onset χ2 p value
Days 0–3 (n = 37) Days 4–7 (n = 69) Days 8–10 (n = 53) Days 11–14 (n = 49) Days 15–21 (n = 25)
Pulmonary opacities
  GGO only 8 (21.6) 13 (18.8) 7 (13.2) 4 (8.2) 1 (4.0) 6.6 0.16
  GGO and consolidation 12 (32.4) 26 (37.7) 8 (15.1) 5 (10.1) 1 (4.0) 22.2 < 0.01
  GGO and linear opacities 2 (5.4) 2 (2.9) 4 (7.5) 2 (4.1) 2 (8.0) 1.87 0.76
  Consolidation only 1 (2.8) 6 (8.7) 3 (5.7) 4 (8.2) 1 (4.0) 1.98 0.74
  Consolidation and linear opacities 0 (0) 2 (2.9) 4 (7.5) 4 (8.2) 3 (12.0) 6.0 0.19
  GGO, consolidation, and linear opacities 12 (32.4) 19 (27.5) 25 (47.2) 30 (61.2) 17 (68.0) 21.5 < 0.01
  Negative CT 2 (5.4) 1 (1.5) 2 (3.8) 0 (0.0) 0 (0.0) 4.3 0.36
Other findings
  Discrete pulmonary nodules 4 (10.8) 4 (5.8) 3 (5.7) 1 (2.0) 0 (0) 4.8 0.36
  Pleural effusion 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) – –
  Lymphadenopathy 0 (0) 0 (0) 0 (0) 0 (0) 0 (0) – –
  Cavitation 3 (8.1) 3 (4.3) 1 (1.9) 2 (4.1) 1 (4.0) 2.1 0.72
Total lung severity score
  Mean ± SD 3.9 ± 2.7 4.8 ± 2.9 4.9 ± 2.8 5.3 ± 3.3 5.2 ± 2.8 – 0.29
  Median (range) 4 (0–10) 5 (0–12) 5 (0–11) 5 (1–13) 5 (1–11) – –