TABLE 1.

Classification of the human coronaviruses^a

Genus	Natural host(s)	Subgenus	Species	Intermediate host	Presence of furin cleavage site
Alphacoronavirus	Mammals dominant		HCoV-229E	Camelids	−
			HCoV-NL63	?	+ (at S2′)
Betacoronavirus	Mammals dominant	Embecovirus	HCoV-OC43	Bovines	+
			HCoV-HKU1	?	+
		Hibecovirus			+
		Merbecovirus	MERS-CoV	Dromedary camels	+
		Nobecovirus			+
		Sarbecovirus	SARS-CoV-1	Palm civets	−
			SARS-CoV-2	Pangolins	+
Gammacoronavirus	Birds dominant; mammals				+
Deltacoronavirus	Birds dominant; mammals				−

^aCoronaviruses belong to the order Nidovirales, family Coronaviridae, subfamily Coronavirinae. “+” indicates presence of furin cleavage site; “−” indicates absence of furin cleavage site; “?” indicates yet to be identified/clarified.