I want to spend a bit of time clearly laying out where #SARSCoV2 probably comes from, and how it could have ended up in Wuhan. Though it can't be ruled out there is currently no, zero evidence for a lab escape scenario while there is ample precedent for zoonotic spillover.
Human exposure to animal viruses occurs every day worldwide, probably multiple times, due to our intense (and unwise for many reasons interactions with wildlife both directly and via agriculture. There are many examples of this resulting in zoonotic infection
and small outbreaks, epidemics, and pandemics that result in animal viruses becoming endemic in humans. Examples include SARS, Ebola, Marburg, smallpox, Nipah, Hendra, Measles, HIV, hantaviruses, arenaviruses and now-endemic human coronaviruses (OC43, 229E, NL63).
Research since 2003 (largely by Wuhan Institute of Virology), shows conclusively that at least dozens of SARS-related (SARSr)-CoVs circulate in bats in Yunnan province in southern China. Although Yunnan is the natural geographic range of these viruses the SARS epidemic started
in Guangdong province, demonstrating that bat SARSr-CoVs are moved outside of their natural range by human transport of infected hosts, including natural hosts such as bats or infected intermediate hosts such as civets and raccoon dogs in the case of SARS.
Research by Chinese and American labs has shown that some of these viruses naturally infect human cells via ACE2, the SARS and #SARSCoV2 receptor showing that while adaptation in intermediate hosts or humans may occur, it is not even necessary. Clearly adaptation via
So what is a plausible scenario for the #SARSCoV2 spillover, relying on ample precedent and evidence of closely related viruses in the wild? The viruses found in pangolins are a critical clue. These viruses were found in Malayan pangolins in Guangxi and Guangdong provinces
that were seized in anti-wildlife trafficking operations outside the native range of both the pangolins and SARSr-CoVs. These may be viruses that circulate in pangolins, or more likely bat viruses that spill over in pangolins similer to the original SARS virus. Either way,
the discovery of these viruses outside their natural range is *proof* that human activity moves SARSr-CoVs around China, large distances away from where they naturally circulate and "belong". Animals from southern China are known to be trafficked beyond Guangdong, given
the documented sale of these animals in the now-infamous seafood market in Wuhan. There is no reason to doubt infected animals (either transiently infected intermediate hosts or established intermediate hosts) are transported across the distance separating southern China and
Wuhan. The distance (~1,000 miles) sounds large but is in fact trivial, less than the distance between Miami and NYC. Therefore, a scenario wherein infected animals are transported from or through the natural range of SARSr-CoVs is not only plausible, but has actually happened
in the past and is documented to have occurred as late as 2017 and 2019 (when the infected pangolins were seized). This trafficking and transport did not end following the 2003 SARS pandemic. In contrast, there is no evidence for the much less extensively documented
history of lab-acquired infections or "escapes" resulting in widespread transmission of animal viruses into the population. Finally, the evidence-free campaign to assign the #COVID19 to a lab escape is incredibly counterproductive from the standpoint of human health. These
viruses circulate in the wild and will continue to do so. This will not be the last zoonotic spillover of SARSr-CoVs. The end of incredibly productive collaboration between western and Chinese scientists can only reduce our ability to identify such spillover events early,
negatively impact efforts to reduce the human-wildlife interface, and mitigate the impact of spillover events. We will be less safe as a results. SARS-CoV-3 is out there, and we must do *everything possible* to prevent anything like this from happening again.
