Just skimmed it, but here's an argument that I never heard before:
"... laboratory escape scenario involves accidental infection in the course of serial passage of a SARSr-CoV in common laboratory animals such as mice. However, early SARSCoV-2 isolates were unable to infect wild-type mice."
It then goes on about a protein that is necessary for mouse infection which only developed in later variants of the virus, but wasn't in the initial outbreak.
Here's a link to the pre-print LINK
Just skimmed it, but here's an argument that I never heard before:
"... laboratory escape scenario involves accidental infection in the course of serial passage of a SARSr-CoV in common laboratory animals such as mice. However, early SARSCoV-2 isolates were unable to infect wild-type mice."
It then goes on about a protein that is necessary for mouse infection which only developed in later variants of the virus, but wasn't in the initial outbreak.
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