Why is SARS-CoV-2 more potent than other coronaviruses?

Of the 7 coronaviruses known to infect humans, only 3 of them, SARS-CoV-2, MERS-CoV and SARS-CoV cause severe disease in humans. SARS-CoV-2 infections spread rapidly and are more fatal. What is the difference between them?

1. Affinity of RBD for ACE2: The receptor-binding domain (RBD) of SARS-CoV-2 has a higher affinity for ACE2 than the RBDs from other coronaviruses. The higher the affinity, the more its ability to infect cells. Higher affinity may be because of a mutation in the RBD⁽¹⁾. 
2. Polybasic furin cleavage site: In SARS-CoV-1, an additional polybasic cleavage site is found at the junction of S1 and S2 which allows effective cleavage by furin. This might have an impact on its transmissibility &  pathogenesis⁽¹⁾.  
3. Cytokine Profile: Cytokine profiles are often perturbed during viral infections.  In individuals with SARS-CoV-2 infection, the level of inflammatory cytokines was significantly higher than normal. In addition, there was significant correlation between cytokine levels and severity of the disease⁽²⁾. The severe cytokine storm is reflected in the severity of the symptoms. Find out which cytokines were affected.

OriGene has launched a comprehensive SARS-CoV-2 Tool Set to investigate the SARS-CoV-2-Human cells interaction. Learn more.

 

 

References
1.  The proximal origin of SARS-CoV-2, Andersen et al, Nature Medicine, 2020
2.  A Review of Coronavirus Disease-2019, Tanu Singhal, Indian Journal of Pediatrics, 87, 281-286 (2020)