Fig. 2. Clinical and radiologic courses from onset of symptoms of 51-year-old patient with COVID-19.

Darkly colored means that degree is severe. Low-grade fever, 37.5–38.2℃; high-grade fever, > 38.3℃; C-reactive protein elevation was divided into < 10, 10–19.9, 20–29.9, ≥ 30 mg/dL; lopinavir/ritonavir and hydroxychloroquine were used as treatment; haziness of chest radiograph was divided into < 10%, 10–49%, 50–69%, ≥ 70% of total lung involvement. ARDS = acute respiratory distress syndrome, ICU = intensive-care unit, PCR = polymerase chain reaction, ROX index = respiratory rate-oxygenation index (calculated as ratio of oxygen saturation/fraction of inspired oxygen)