Table 1 Characteristics of SARS-CAoV and SARS-CoV-2

Virological characteristics

Classification

the SARS cluster

bat-like coronavirus cluster

Amino acid composition of ORF8b

aggregation motif VLVVL in SARS-CoV ORF8b

no functional domain or motif in SARS-CoV-2 ORF8b

Number of amino acids encoding 8b protein

84

121

Number of amino acids encoding 3b protein

154

67

ORF3b protein

/

having four helices

8a protein

existing

nonexistent

Epidemiological characteristics

sources of infection

wild animals, patients

wild animals, patients and asymptomatic infector

intermediate host

civet

Pangolin?

routes of transmission

respiratory tract transmission, contact transmission

respiratory tract transmission, contact transmission, may be including digestive tract transmission?, urine? and mother-to-child transmission?

susceptible populations

susceptibility to the entire population, mainly in adults

susceptibility to the entire population

Infectiousness(R₀)

2–3

1.2–3.58 [42, 136–139]

crude death rate

11%

1.4–7.0% [140–143]

Clinical characteristics

respiratory symptoms

High fever, cough are common

low fever, and temperature does not rise in some cases, cough

Gastrointestinal symptoms

Common (diarrhea is rare)

uncommon; can be the initial symptoms

cardiovascular symptoms

/

palpitations and chest pain can be the initial symptoms

concominant diseases

including cardio-cerebrovascular diseases, hypertension, diabetes

higher frequency including cardio-cerebrovascular diseases, hypertension, diabetes

imaging features

pulmonary consolidation and exudation

ground glass opacity, pulmonary consolidation and exudation

pathological characteristics

lung

pulmonary edema accompanied by exudation of fibrin; Pulmonary fibrosis is a common characteristic.

pulmonary edema accompanied by exudation of fibrin; mainly mucus exudation; thrombi within peripheral small vessels in lungs.