SARS‐CoV‐2 not made in a laboratory

There has been much speculation but a spectacular lack of evidence that SARS‐CoV‐2 originated from a laboratory. Researchers compared the genome of SARS‐CoV‐2 with those of the other six coronaviruses known to infect humans: SARS‐CoV and MERS‐CoV, which like SARS‐CoV‐2 can cause severe disease, and HKU1, NL63, OC43 and 229E which generally cause mild disease. ¹ SARS‐CoV‐2 is (i) optimised for binding to the human ACE2 receptor; and (ii) its spike protein has a unique polybasic cleavage site which facilitates cell entry and led to the predicted acquisition of three O‐linked glycans that provide immune evasion. Genetic data show SARS‐CoV‐2 is not derived from any previously used virus backbone. Although bat SARS‐CoV‐like coronaviruses have been grown in cell culture and animal models for research world‐wide, and despite some documented laboratory escape of such viruses, genetic analysis does not support that SARS‐CoV‐2 resulted from inadvertent laboratory release. The receptor‐binding domain in the spike protein of SARS‐CoV‐2 closely resembles the receptor‐binding domain in known pangolin coronaviruses, which makes them a likely origin. The origin of the unique cleavage site has not been discovered, but is expected to have arisen in a wild‐type coronavirus and argues against culture‐based scenarios. The authors argue that all the available evidences indicate that SARS‐CoV‐2 arose by natural selection, either in an animal host before zoonotic transfer or in humans following initial cryptic zoonotic transfer. What is clear is that SARS‐CoV‐2 is not a laboratory construct or a purposefully manipulated virus.