Table 2.
Comparison of Reported Lung Histopathology Features in COVID-19, 2009 H1N1 Influenza A, and SARS
| Virus | No. of Patients | DAD | AFOP | Organizing Fibrosis | End-stage Fibrosis | Superimposed PNA | Microthrombi | Pulmonary Thrombosis |
|---|---|---|---|---|---|---|---|---|
| COVID-19 | 171 | 88% (151) | 4% (6) | 52% (89) | 1% (1) | 32% (55) | 57% (97) | 15% (25) |
| 2009 H1N1 Influenza A | 287 | 90% (258) | 0.3% (1) | 40% (115) | 3% (8) | 30% (86) | 24% (70) | 6% (18) |
| SARS | 64 | 98% (63) | 9% (6) | 47% (30) | 6% (4) | 31% (20) | 58% (37) | 28% (18) |
All reported numbers are the proportion and number of patients (in parentheses) reported to have the respective finding within each viral cohort. AFOP = acute fibrinous and organizing pneumonia; COVID-19 = coronavirus disease 2019; DAD = diffuse alveolar damage; PNA = pneumonia; Pulmonary thrombosis: pulmonary vessel thrombosis; SARS = severe acute respiratory syndrome.