Figure 1.

Disease progression in the study patients.

Clinical severity was classified according to the eight-category ordinal scale developed by Sung et al. (2020). “Mild” means 1) without limitations in daily activities or 2) with limitations in daily activities but without a need for supplemental oxygen therapy. “Moderate to severe” refers to the need for 3) supplemental oxygen therapy through a nasal cannula, 4) supplemental oxygen therapy through a facial mask, or 5) high-flow supplemental oxygen therapy or noninvasive mechanical ventilation. None of the patients in this study 6) needed invasive ventilation, 7) multi-organ failure or extracorporeal membrane oxygenation (ECMO) or 8) died.