New WHO Report Affirms Need to Study SARS-CoV2 Lab Leak Theory – Alongside Spillover Narrative
Chinese wet market

The first report by the new WHO-convened expert group, Scientific Advisory Group for the Origins of Novel Pathogens (SAGO) has fanned the flames of controversy over evidence about whether a lab leak or a natural “spillover” of the virus from animals to humans was the most likely source from which the COVID pandemic emerged – although in fact it contains little new information on either. 

The preliminary SAGO report, published Thursday, is significant in that it redresses some of the perceived pro-China “biases” of WHO’s first report by an international group of experts on the virus origins issued in March 2021.  

The report marks the first formal acknowledgement by a WHO-sponsored expert group that a possible biosafety failure in the Wuhan Virology Institute should be further investigated as the pandemic trigger – stating: “it remains important to consider all reasonable scientific data that is available through published or other official sources to evaluate the possibility of the introduction of SARS-CoV-2 into the human population through a laboratory incident.” 

The lab escape theory was something the previous WHO international expert group that also visited Wuhan China in January 2021, had discounted as “extremely unlikely” – provoking a political and scientific uproar by critics who said that group lacked adequate biosafety expertise or evidence to draw that conclusion, and had been politicized by its Chinese participants.  

The new WHO report also calls attention to the continuing political barriers to studies that get at the roots of the SARS-CoV2 narrative – including the lack of access to individual patient data and blood samples from tens of thousands of confirmed and suspected SARS-CoV2 cases from late 2019 and early 2020 that China has refused to share, as well as a lack of comparable data from animal studies.  

No intermediate host or spillover event clearly identified

Blyth’s Horseshoe Bat (Rhinolophus lepidus)
Location: Bandhavgarh National Park, Umaria, Madhya Pradesh, India

The committee confirms long-stated claims that the virus originated in bats, “with the closest genetically related viruses being beta coronaviruses, identified in Rhinolophus bats in China in 2013 (96.1%) and Laos in 2020 (96.8%). However, so far neither the virus progenitors nor the natural/intermediate hosts or spill-over event to humans have been identified. 

“Early investigations suggested that the Huanan seafood market in Wuhan played an important role early in the amplification of the pandemic with several of the patients first detected in December 2019 having had a link to the market and environmental samples from the market testing positive…. 

However, the report also concludes that  “the source of SARS-CoV-2 and its introduction into the market is unclear and it is yet to be determined where the initial spillover event(s) occurred….  Furthermore, follow-up studies to identify possible animal sources from which the environmental contamination could have originated have not been completed.” 

In fact, there is so far little new evidence that has really been brought to the table on either the spillover or lab leak theories, WHO sources told Health Policy Watch. These sources stressed that the report remains preliminary in nature and that a final version may hopefully include more definitive information. 

China, Russia and Brazil object to further studies on lab escape studies 

While the report recommends further research into whether a lab biosafety failure could have triggered the SARS-CoV2 outbreak – it also admits, in roundabout diplomatic language, that the prospects for obtaining key information from China on biosafety conditions at the Wuhan Institute of Virology that studied bat coronaviruses in Wuhan, that remain  dim. 

“To support biosafety and biosecurity investigations into the introduction of SARS-CoV-2 into the human population through a laboratory incident; the SAGO notes that there would need to be access to and review of the evidence of all laboratory activities (both in vitro and in vivo studies) with coronaviruses including SARS-CoV-2-related viruses or close ancestors, and the laboratory’s approach to implementation and improvement of laboratory biosafety and biosecurity,” the report states. 

“As it is not common practice to publish the institutional implementation of biosafety and biosecurity practices of individual laboratories in peer-reviewed scientific journals, additional information will need to be obtained and reviewed to make conclusive recommendations.”

Notably, the SAGO team’s three scientists from China, Russia and Brazil, objected to further pursuit of the lab escape theory, as reported in a footnote that states: 

“Dr Vladimir Dedkov, Dr Carlos Morel, Professor Yungui Yang do not agree with the inclusion of further studies evaluating the possibility of introduction of SARS-CoV-2 to the human population through a laboratory incident in this preliminary report due to the fact that from their viewpoint, there is no new scientific evidence to question the conclusion of the WHO-convened global study of origins of SARS-CoV-2: China Part mission report published in March 2021.”

Battle between spillover versus lab escape adherents in scientific circles 

lab leak
Seafood and fresh food market in Wuhan, Hubei, China. Most confirmed cases of SARS-CoV2 were traced back to Huanan Wholesale Seafood Market.

Outside of the SAGO group – a fierce battle also continues to rage over the merits of the “lab escape” versus “natural spillover” theories. 

And if anything the new report only seemed to fan the flames of arguments on both sides – with adherents to one theory or the other facing off in the media over the merits of the report.

Experts urging more attention to the natural spillover theory lamented that the WHO report did not seem to give enough credit to recent studies of SARS-CoV2 samples found in the Huanan Seafood Wholesale Market, which have been published, but not yet peer-reviewed. 

“I think if you read our pre-prints and understand the evidence, actually there’s very strong evidence that the pandemic emerged through wildlife at the Huanan market,” the lead author of two such studies, Michael Worobey of the University of Arizona, was quoted as saying

Worobey and his colleagues pieced together the genetic evidence about the virus’ presence and evolution in studies of Wuhan residents in early 2020 as well as analysis of environmental samples taken from Wuhan’s live animal markets between December 2019 and February 2020. Some of those environmental samples showed high levels of SARS-CoV2 in areas in and around the cages of racoon dogs, being sold for slaughter – although no “Animal X” was identified. And critics also have said the sample size is too small to be conclusive. 

Lab biosafety advocates express satisfaction with report’s findings

On the other side of the fence, Richard H Ebright, a scientist at Rutgers University an advocate of further research on the potential biosafety failures, welcomed the new WHO report’s balance, telling Health Policy Watch

“The SAGO report concludes that, based on available data, it is not possible to determine whether SARS-CoV-2 entered humans through natural spillover or through research-related spillover.

“This conclusion will be anathema to those who have falsely claimed over the last two years that science shows SARS-CoV-2 entered humans through natural spillover.”

Ebright also welcomed the report’s call for “strengthening of regulation of biosafety, biosecurity, and biorisk management for pathogens research, with special attention to regulation of gain-of-function research” as part of a broader Global Framework to prevent future pathogen risks from emerging.  

“The recommendations on strengthening of regulation in the SAGO report  closely track those of a second WHO report that was released just over a week ago, that has gotten no news coverage,” he added. 

Missing gene sequence data and phylogenetic studies also under debate 

Partisans of further research into a possible biosafety failure also have pointed to SARS-CoV2 gene sequence data “deleted” by Chinese researchers early on in the pandemic from a US National Institutes of Health database as evidence of a possible cover-up.  

And recent phylogenetic studies of the virus’ family tree don’t necessarily correlate with a narrative of an initial natural spillover from animals to humans in Wuhan’s markets either, the critics say – although that claim is hotly disputed by Worobey.   

Said Jesse Bloom, a virologist with the Seattle-based Fred Hutch Research Institute: 

“I still think, (1) early COVID-19 case & sequence data that have been released by the Chinese government are likely incomplete; 

(2) for this reason, the origin of human #SARSCoV2 in Wuhan remains unclear.” 

Framework for Way Forward 

In light of the barriers faced in obtaining more original data from Chinese government sources relevant to either the lab leak or natural spillover narratives, the most constructive role that the SAGO group may have to play going forward could be in  the synthesis of  work by virus hunting scientists around the world.

The report also strikes a forward-looking note, etching out a broad “Global Framework” for how scientists should take forward research into practices and policies along the whole chain of l risks, from food safety to lab security – all critical in preventing future pandemics. 

That new framework should include:   

  • Studies of zoonotic  risks in animal groups and marketplaces;
  • Reviews of existing legislation and governance mechanisms related to lab biosafety;
  • Studies of epidemiological samples of human patients, including blood and viral samples. 

Concluded Bloom: “Continuing to openly study the possible origins of the virus is crucial both for the sake of science itself, and to design strategies to mitigate the future risks of both zoonotic and lab-based outbreaks.”   

Image Credits: dietertimmerman, abhijeet jagtap/Flickr, Arend Kuester/Flickr.

Combat the infodemic in health information and support health policy reporting from the global South. Our growing network of journalists in Africa, Asia, Geneva and New York connect the dots between regional realities and the big global debates, with evidence-based, open access news and analysis. To make a personal or organisational contribution click here on PayPal.