Theories about the origins of the COVID-19 outbreak have been spreading as fast as the virus itself. Many have focused on the presence of one of China’s most advanced virus research laboratories, the Wuhan Institute of Virology (WIV), to suggest SARS-CoV-2 may have originated in a lab.
What does the evidence tell us?
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The first popular lab theory, put forward in a January 26 article in the Washington Times, suggested COVID-19 was the result of biological warfare gone wrong. The article, which likely spawned a million WhatsApp forwards, quoted a former Israeli military officer as saying the virus “may have originated in a laboratory in the city of Wuhan linked to China’s covert biological weapons program.”
A March 17 study by several virologists, including Kristian Andersen of The Scripps Research Institute and Ian Lipkin at Columbia University, concluded the evidence suggests SARS-CoV-2 was not engineered. The study, The proximal origin of SARS-CoV-2, concluded based on available genome sequence data, that has now been mapped in several countries, that “it is improbable that SARS-CoV-2 emerged through laboratory manipulation of a related SARS-CoV-like coronavirus”. The virus sequence was 96% identical at the whole-genome level to a bat coronavirus. It suggested two possible origins: “natural selection in an animal host before zoonotic transfer” and “natural selection in humans following zoonotic transfer.”
If we can now assume the origins were natural, the source remains a mystery. Whether the original source, presumably a bat, was being studied at a lab (we know the WIV did indeed research bat coronaviruses), sold at a market, or infected another animal that was sold at a market remains a matter of pure conjecture.
Could the virus have leaked from the lab in an accident? Some lab leak advocates have pointed to 2018 U.S. State Department cables expressing serious concerns over safety practices at the WIV. Others cite a February 6 study by Xiao Botao of the South China University of Technology, which has since been deleted. Though widely cited, the paper has not been peer-reviewed, is just one page long, and only cites circumstantial evidence, pointing to the WIV and Wuhan Center for Disease Control being 12 km and 280 metres from the first infection cluster at a seafood market.
The likelihood of lab origins hinges on whether SARS-CoV-2 was one of the viruses being studied at the lab. Scientists at the WIV have denied this was the case. Opening up the lab to foreign researchers might shed some light, but even that may not quell doubts given the secrecy with which such labs operate, more so those located in China. The Chinese government putting in place new rules that require research on the origins to be vetted has only raised more doubts.
What may disprove a lab origin theory is if an intermediate host is identified, suggesting a natural spillover, but that could take years. In a strange irony, scientists at the WIV, including top expert Shi Zhengli, published a paper in Nature in December 2018 on the Origin and Evolution of Pathogenic Coronaviruses warning of the increasing dangers of spillovers of bat coronaviruses, because of human activities bringing them in close proximity to bats. Their prior research, in fact, helped map the SARS-CoV-2 genome in record time. Now that their warnings have come true, they find themselves being blamed for the new virus.
There is no evidence to prove or disprove a lab leak. In the scientific community, new theories are usually regarded as credible based on the evidence with which they are offered; they aren’t believed to be true until evidence disproves them. That isn’t, however, how the rest of the world operates. This may explain why the lab leak theory appears to be less popular with scientists than it is with politicians, journalists and foreign policy experts. Which side of the debate you stand on may have less to do with a question of science than your political beliefs, even if this still unanswered question is one perhaps best left to the scientists.
ananth.krishnan@thehindu.co.in