This week’s testimony by former CDC director Dr Robert Redfield to US Congress has reignited widespread speculation in the United States that the SARS-CoV-2 virus first emerged in a Wuhan research laboratory rather than in animals. The scientific debate about the origins of the virus took off this week just before the three-year anniversary of the World Health Organization’s declaration of the pandemic on 11 March 2020.

Redfield’s testimony on Wednesday, in which he stated it was “not scientifically plausible” that the virus had natural origins, comes on the heels of several weeks of US media reports that revealed support for the laboratory leak theory in several US government agencies. 

To sceptics, the information shared by Redfield and others remains “anecdotal”. Three years and 7 million deaths from the start of COVID-19’s global assault, researchers stress that the world is a long way from having definitive answers to how the SARS-CoV-2 virus made the jump to humans. 

The three keys to Redfield’s testimony 

In his testimony, Redfield, director of the CDC under former president Donald Trump at the onset of the pandemic, told Congress about three events that occurred shortly before the pandemic began which led him to believe the virus emerged from laboratory biosecurity failures.  

Those included a shift from Chinese civilian to military control of the lab and renovations to the facility’s ventilation system, as well as the deletion of the Wuhan Institute of Virology’s research database on coronavirus genome sequences that it was researching.

“The declassified information now shows in September 2019, three things happened in that lab,” Redfield told the Congressional subcommittee. Convened by the Republican House majority, the bipartisan group is once again investigating the origins of SARS-CoV-2. “Clearly there is strong evidence that a significant event happened in that laboratory in September.”  

“One is they deleted the sequences,” he said in reference to an online database of genome sequences of bat-related coronaviruses, which was taken offline  in September 2019 and has not resurfaced since. “That is highly irregular. Researchers don’t usually like to do that.”

“The second thing they did is they changed command and control of the lab from civilian control to military control. Highly unusual,” Redfield said, without elaborating his sources.

Media reports have shown that WIV likely operated as a “dual-use” facility with civilian and military functions and hosted military scientists.

One military scientist hosted by WIV was Zhou Yusen, director of the State Key Laboratory of Pathogen and Biosecurity at the Academy of Military Medical Sciences Institute of Microbiology and Epidemiology in Beijing, a joint investigation by ProPublica and Vanity Fair found.  He began researching coronaviruses as early as 2012, and was one of the first scientists to apply for a vaccine patent. 

“The third thing they did I think is really telling,” Redfield said. “They let a contractor redo the ventilation system in that laboratory.”  

Prior Congressional investigations tend to support Refield’s claim on the ventilation issues that plagued the Institute. In August 2021, the House Select Committee on COVID-19 released a memo detailing the malfunctioning of multiple air ventilation systems inside WIV in the months leading up to the pandemic.

Other media reports from 2021 suggested that the renovations on the defective ventilation systems were launched shortly before the pandemic exploded.

Department of Energy report  

Redfield’s testimony follows the leak of a recent US Department of Energy report to the Wall Street Journal. The new DOE report assessed that COVID-19 “most likely” came from a lab leak. The agency described its assessment as “low-confidence”. 

The DOE assessment is significant due to the agency’s scientific expertise. It runs a total of 17 biolabs across the country, including Lawrence Livermore National Laboratory, which conducts high-level military research into biological weapons including viruses. US officials have declined to provide details on the intelligence that led to the DOE’s updated position. 

That report a Fox News appearance by FBI director Chrisopher Wray in which he said the bureau has “for quite some time” assessed that the origins of the pandemic are “most likely a potential lab incident in Wuhan.”

Despite differing analyses, Redfield, the classified Department of Energy report, and FBI all concluded that the lab leak was accidental and not the result of a Chinese biological-weapons programme.

A US intelligence community review ordered by President Biden in May 2021 produced two more points of consensus across all US agencies: that the virus first appeared in Wuhan no later than November 2019, and that it emerged without the foreknowledge of the Chinese government. 

“Show me the evidence”

Despite the noise and political theatre of the Congressional hearings, the Department of Energy report remains classified, and the FBI has declined to comment further on the evidence underpinning the bureau’s “moderate confidence” in the lab leak theory. 

Other US agencies, privy to the classified assessments of the DOE and FBI, have not changed their position despite the new evidence. 

The World Health Organization has said that while zoonotic spillover remains the likeliest point of origin, the lab leak theory cannot be ruled out. WHO has said its investigation will continue until a definitive origin is identified. 

For many scientists, the classified nature of the US government reports make them impossible to assess. They have called for more transparency around the recent documentation. 

“I’m a scientist. I need to see the evidence rather than take the FBI director’s word for it,” University of Saskatchewan virologist Angela Rasmussen told the Associated Press. “The vast majority of the evidence continues to support natural origin.”

In contrast to the evidence supporting the lab leak theory, the reasoning behind the animal origin is publicly available. In an influential set of peer-reviewed papers published in July, researchers concluded that SARS-CoV-2 “occurred through the live wildlife trade in China” via the Wuhan market. 

Stephen Goldstein, a virologist at the University of Utah and one of the paper’s co-authors, remains open-minded about the lab leak theory. But like Rasmussen, says it is impossible to assess without access to the evidence. 

“It’s very difficult to say anything until we see what information drove this [DOE] updated analysis,” Goldstein told Vanity Fair. “If the data exists and is declassified and I can update my own analysis, wonderful.”

SARS-CoV2 lacks molecular structure of an engineered virus

Redfield’s view that the virus could not have had natural origins is widely disputed by scientists. The SARS-CoV-2 virus has no known backbone, a critical molecular structure on which all engineered viruses are built, making it a bad candidate for bioengineering. 

“Virologists cannot create or design viruses out of thin air,” Robert Garry, professor of microbiology and immunology at Tulane University told the New Republic. “There would need to be at least something close to it in nature.”

The polarized nature of discussion around the origins of SARS-CoV-2 also overshadow a potential middle-ground: the virus was found in nature was brought to the Institute for study. But without the cooperation of Chinese authorities, no evidence that the virus was being studied at the lab has emerged.

Until the full-scope of the work that took place at the Wuhan Institute is made public, the origins of the virus that has killed over seven million people are likely to remain a mystery.

Image Credits: NIH, Creative Commons, LLN, FBI.