Table 1.

Essential features of SARS-CoV, MERS-CoV, and SARS-CoV-2

	First described human cases/country	Bat reservoir	Intermediate host or animal reservoir	Transmissibility between humans	Mode of transmission	Cellular receptor	Number of confirmed cases (5.3.21)	Case fatality rate (%)
SARS-CoV	February 2003 Guangdong, China	Rhinolophus species	masked palm civet (Paguma larvata) or raccoon dogs (Nyctereutes procyonoides)	moderate, R0: ∼1	respiratory droplets, surfaces	ACE2	8,096	9.6
MERS-CoV	April 2012 Saudi Arabia	Neoromicia, Pipistrellus	dromedary (Camelus dromedaries)	low, R0: <1	close contact	dipeptidylpeptidase 4	2,468	35
SARS-CoV-2	December 2019, Wuhan, China	Rhinolophus species?	Unknown	high, R0: ∼3	aerosol, droplets	ACE2	115,655,792	2.3

Data from WHO:

SARS-CoV: https://www.who.int/health-topics/severe-acute-respiratory-syndrome#tab=tab_2

https://www.who.int/publications/m/item/summary-of-probable-sars-cases-with-onset-of-illness-from-1-november-2002-to-31-july-2003

MERS-CoV: https://www.who.int/health-topics/middle-east-respiratory-syndrome-coronavirus-mers#tab=tab_1

SARS-CoV-2: https://www.who.int/health-topics/coronavirus#tab=tab_1

R0 is the basic reproduction number: expected number of cases generated by one case in a population where all individuals are susceptible to infection.

Case fatality rate is likely an overestimation since mild and asymptomatic cases are missed by surveillance systems.