Ralph S. Baric, Ph.D.
NEJM, December 16, 2020 DOI: 10.1056/NEJMcibr2032888 Fulltext için tıklayınız
Sarbecoviruses have emerged twice in the 21st century, causing a worldwide epidemic and pandemic. The ongoing pandemic of coronavirus disease 2019 (Covid-19), the disease caused by severe acute respiratory syndrome coronavirus 2 (SARSCoV-2), has caused unprecedented disruption of human society. Since its emergence in December 2019, SARS-CoV-2 has spread worldwide, infecting more than 70 million persons and causing more than 1.6 million deaths as of early December 2020. Previous studies have clearly shown that epidemic and pandemic RNA virus spread may select for mutations that alter RNA virus pathogenesis, virulence, transmissibility, or a combination of these,1
yet this process remains poorly studied among emerging coronaviruses in animals and humans.
SARS-CoV-2 probably emerged from bats, and early strains identified in Wuhan, China, showed limited genetic diversity, which suggests that the virus may have been introduced from a single source.2
Early zoonotic variants in the novel coronavirus SARS-CoV that emerged in 2003 affected
the receptor-binding domain (RBD) of the spike protein and thereby enhanced virus docking and entry through the human angiotensin-converting– enzyme 2 (hACE2) receptor.3
In contrast, the spikeprotein RBD of early SARS-CoV-2 strains was shown to interact efficiently with hACE2 receptors early on.2
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