The Origins of SARS-CoV-2 – Critical Review

Prof. Joel Eissenberg: “Zoonotic origin for SARS-CoV-2 remains the most plausible hypothesis”

There’s a saying in research science: extraordinary claims require extraordinary evidence. Given what we know about the origins of nearly all viral pandemics — that they resulted from a virus jumping from an animal to a human host (zoonotic infection)–the null hypothesis for the origin of the COVID-19 pandemic should be and was zoonotic. The competing claim the SARS-CoV-2 originated in a research lab at the Wuhan Institute for Virology (WIV) has been widely circulating on conspiracy theory web sites.

Based on what we know about SARS-CoV-2 genome structure, comparative coronavirus genomics and viral epidemiology in general, it is fair to say that the burden of proof falls upon those who support the lab origin hypothesis. According to a recent preprint review, this burden has not been met, and the most parsimonious hypothesis is a zoonotic origin. The authors also underscore the importance of further research to define the origin of COVID-19 and the danger of distracting claims to the research necessary to prepare for future pandemics:

“There is currently no evidence that SARS-CoV-2 has a laboratory origin. There is no evidence that any early cases had any connection to the WIV, in contrast to the clear epidemiological links to animal markets in Wuhan, nor evidence that the WIV possessed or worked on a progenitor of SARS-CoV-2 prior to the pandemic. The suspicion that SARS-CoV-2 might have a laboratory origin stems from the coincidence that it was first detected in a city that houses a major virological laboratory that studies coronaviruses. Wuhan is the largest city in central China with multiple animal markets and is a major hub for travel and commerce, well connected to other areas both within China and internationally. The link to Wuhan therefore more likely reflects the fact that pathogens often require heavily populated areas to become established. 

“We contend that there is substantial body of scientific evidence supporting a zoonotic origin for SARS-CoV-2. While the possibility of a laboratory accident cannot be entirely dismissed, and may be near impossible to falsify, this conduit for emergence is highly unlikely relative to the numerous and repeated human-animal contacts that occur routinely in the wildlife trade. Failure to comprehensively investigate the zoonotic origin through collaborative and carefully coordinated studies would leave the world vulnerable to future pandemics arising from the same human activities that have repeatedly put us on a collision course with novel viruses.”

The Origins of SARS-CoV-2: A Critical ReviewThe Origins of SARS-CoV-2: A Critical Review Holmes et al. Since the first reports of a novel SARS-like coronavirus in December 2019 in Wuhan, China, there has been intense interest in understanding how SARS-CoV-2 emerged in the human population. Recent debate has coalesced around two competing ideas: a “laboratory escape” scenario and zoonotic emergence. Here, we critically review the current scientific evidence that may help clarify the origin of SARS-CoV-2.