TABLE 2.

Summary of evidence that would support each of the two theories

	For direct zoonosis	For laboratory-related origin
Existing evidence	Sequence similarity to other zoonotic coronaviruses	Evidence of laboratory work with coronaviruses isolated from bats
	Recent precedent for spillover of coronaviruses (SARS, MERS, canine-feline coronavirus)	Precedent of prior accidents in research laboratories
	Precedent for Spike RBD that can bind ACE2 receptor in bat and pangolin viruses
Potential additional evidence	Discovery of SARS-CoV-2 or a direct ancestor in the wild	Evidence of laboratory work with SARS-CoV-2 or a close ancestor
	Serological evidence for SARS-CoV-2 in feral animals	Evidence that laboratory passaged a more distantly related virus that acquired the ability to bind ACE2 while retaining SARS-CoV-2 backbone
	Discovery of SARS-CoV-2 in an “intermediate” species
	Discovery of SARS-CoV-2 in archival material	Clinical evidence that a researcher(s) was infected with SARS-CoV-2 before Dec 2019
	Finding of SARS-CoV-2 antibodies in archival human or animal serum samples