1. WHO clinical progression scale.

Patient State	Descriptor	Score
Uninfected	Uninfected; no viral RNA detected	0
Ambulatory mild disease	Asymptomatic; viral RNA detected	1
	Symptomatic; independent	2
	Symptomatic; assistance needed	3
Hospitalised: moderate disease	Hospitalised; no oxygen therapya	4
	Hospitalised; oxygen by mask or nasal prongs	5
Hospitalised: severe disease	Hospitalised; oxygen by non‐invasive mechanical ventilation or high flow	6
	Intubation and mechanical ventilation, pO2/FiO2 ≥ 150 or SpO2/FiO2 ≥ 200	7
	Invasive mechanical ventilation pO2/FiO2 < 150 (SpO2/FiO2 < 200) or vasopressors	8
	Invasive mechanical ventilation pO2/FiO2 < 150 and vasopressors, dialysis or ECMO	9
Dead	Dead	10

WHO clinical progression scale from: WHO 2020e

^aIf hospitalised for isolation only, record status as for ambulatory patient

ECMO: extracorporeal membrane oxygenation

FiO_2: fraction of inspired oxygen

pO_2: partial pressure of oxygen

SpO_2: oxygen saturation