Table 1.

WHO Ordinal Scale for Clinical Improvement

	Score
Uninfected
No clinical or virological evidence of infection	0
Ambulatory
No limitation of activities	1
Limitation of activities	2
Hospitalised (mild disease)
Hospitalised (no oxygen therapy)	3
Oxygen by mask or nasal prongs	4
Hospitalised (severe disease)
Non-invasive ventilation or high-flow oxygen	5
Intubation and mechanical ventilation	6
Ventilation plus additional organ support: pressors, renal replacement therapy, extracorporeal membrane oxygenation	7
Dead
Death	8