Table 1.

WHO ordinal scale for clinical improvement

Patient State	Descriptor	Scale
Uninfected	No clinical and virological evidence of infection	1
Ambulatory	No limitation of activities	2
	Limitation of activities	3
Hospitalised mild disease	Hospitalised, no oxygen therapy	4
	Oxygen by mask or nasal prong	5
Hospitalised severe disease	Non-invasive ventilation or high-flow oxygen	6
	Intubation and mechanical ventilation	7
	Ventilation + additional organ support -pressors, ECMO, RRT	8
Dead	Death	9

ECMO extracorporeal membrane oxygenation, RRT renal replacement therapy, WHO World Health Organisation