‘It’s a very difficult thing to pin down’: Did Covid-19 originate from a ‘lab leak’?

In late February, The Wall Street Journal published a shocking report. Investigators at the US Energy Department had concluded with “low confidence” that the Covid-19 pandemic most likely originated from a laboratory leak in Wuhan, China.

The finding seemed to fly in the face of measured assurances from scientists and government officials who insisted the disease, like all other pandemics before it, originated when an animal virus crossed over into humans sometime in the fall of 2019 in China. The conclusion, in a space of days, seemed to validate claims from Republican politicos and China hawks alike, which had previously been dismissed as conspiracy theories and over-heated partisan attacks.

The FBI has also concluded, with “moderate confidence,” that a Covid lab leak was the most likely origin, while the National Intelligence Council and four other other top government agencies retain a “low confidence” assessment that the disease began zoonotically.

So, has the world of Covid knowledge really been flipped upside down? Not quite, according to coronavirus experts.

According to environmental and occupational health sciences professor Gerard Cangelosi, associate dean for research at the University of Washington School of Public Health, the DOE’s findings, which the agency acknowledged it only held with “low confidence,” represent a conclusion “slightly better than a coin flip.”

“We know nothing for sure,” he told The Independent, noting that the DOE’s evidence for its findings haven’t been made public for review. “Anyone who claims to know how it arose is fooling themselves. That should always be established. It really really takes a long time to figure these things out. We still don’t know exactly where HIV came from. We don’t know exactly where 1918 flu came from. It’s a very difficult thing to pin down.”

Instead, he prefers to start from what we do know.

“Every single infectious disease that we’ve ever known arose naturally,” he continued. “In most cases, zoonotically, meaning it started in an animal species and made a jump to humans. That alone makes it seem most plausible that’s how SARS-CoV-2 started.”

The early cluster of cases that began in the fall of 2019 around Wuhan, China, could’ve still infected workers studying coronaviruses at nearby labs – a lab leak and natural origins are not “mutually exclusive,” Professor Cangelosi noted – but the public health expert said there is no evidence that concretely suggests Covid began as an experiment in a Chinese lab and spread across the world after an accident, as many on the right would have you believe.

“The evidence I’ve seen is largely circumstantial that the Chinese are hiding something,” he said. “That’s not evidence.”

Other experts agree.

“All the evidence available for scrutiny points to the pandemic originating from transmission from live animals to humans,” Angela Rasmussen, a virologist at Vaccine and Infectious Disease Organization at the University of Saskatchewan who co-authored one of the major 2022 studies on Covid’s origins, wrote this month in The Washington Post.

“One thing everyone involved in studying the origins of SARS-CoV-2 seems to agree on — FBI and Energy Department included: No laboratory modification of a virus was involved,” she added. “Indeed, there has never been an infection reported as a result of a pathogen generated through gain-of-function research.”

Instead, we’re left with a mix of uncertainty and educated guesses, a reality when studying pandemics, where the exact contours of a disease’s journey around the world are often calculated probabilistically rather than with exact, crime-scene precision.

A Republican-led committee in the House of Representatives held a contentious public hearing on the origins of Covid recently, the first in a planned series and a sign that the debate over the early days of the pandemic isn’t going away any time soon. We may never know the precise moment the coronavirus jumped into humans, but the long-running fight over its origins has revealed not only lapses in global pandemic preparedness, but the long shadow of partisanship that might hamstring our response to the next infectious disease that inevitably crosses over.

The first cluster of Covid cases can be traced back to the Huanan Seafood Wholesale Market in Wuhan, according to researchers, where vendors sold animals like raccoon dogs and red foxes in late 2019 that can both get and shed the disease which causes Covid. The creatures were photographed near stalls where scientists later found Covid on surfaces like cages, carts, and machines that process slaughtered animals.

The earliest known patient at the market, later the site of an early cluster, had symptoms as of 10 December 2019, when between 10 and 70 people had Covid worldwide, according to genetic analysis.

Michael Worobey, an evolutionary biologist at the University of Arizona who extensively studied the early days of the disease, told NPR in February that there’s an “absurd” level of evidence tying the early outbreak of the disease to the area around the market

“We do have one analysis where we show essentially that the chance of having this pattern of cases [clustered around the market] is 1 in 10 million [if the market isn’t a source of the virus]. We consider that strong evidence in science,” he told the broadcaster. “The analyses that we’ve done are telling a very strong story. The evidence is amongst the best we have for any emerging virus.”

Professor Worobey’s findings were published in an extensive, peer-reviewed paper in Science last summer, but there hasn’t always been such concrete evidence to work with.

With so much unknown about Covid’s origins, especially during its early days, scientists quickly had to start fending off conspiracy theories as they raced to analyse the rapidly spreading disease.

In a February 2020 letter in The Lancet, a prestigious medical journal, a group of top scientists condemn those arguing Covid had an unnatural origin somewhere in a lab in China.

“We stand together to strongly condemn conspiracy theories suggesting that COVID-19 does not have a natural origin,” the letter reads. “Scientists from multiple countries have published and analysed genomes of the causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and they overwhelmingly conclude that this coronavirus originated in wildlife, as have so many other emerging pathogens.”

That didn’t stop partisan actors from jumping into the fray, such as White House trade adviser Peter Navarro, who speculated wildly that the Chinese wanted to “weaponise” Covid and “sent hundreds of thousands of Chinese nationals over here to seed and spread the virus.” Donald Trump, meanwhile, had taken to describing the pandemic with the racist epithet “kung flu.”

Eventually, though, questions about the origins of Covid and a possible lab leak entered more scientific quarters.

In May of 2021, another group of prominent scientists called for investigating both the natural spillover and lab leak theory of Covid, writing in Science “knowing how COVID-19 emerged is critical for informing global strategies to mitigate the risk of future outbreaks.”

“SARS-CoV-2 could have spent some time in a laboratory before encountering humans,” one of the letter’s authors, Stanford University professor of microbiology and immunology David Relman, explained in 2021. “We know that some of the largest collections of bat coronaviruses in the world — and a vigorous research program involving the creation of ‘chimeric’ bat coronaviruses by integrating unfamiliar coronavirus genomic sequences into other, known coronaviruses — are located in downtown Wuhan. And we know that laboratory accidents happen everywhere there are laboratories.”

That year, following a joint investigation with China, the World Health Organization concluded it was “extremely unlikely” Covid leaked from a lab, though criticisms from both within and without acknowledge that Chinese officials weren’t fully forthcoming during the process, blocking access to some forms of patient data. Plans for a second phase of investigation, including potentially auditing individual labs, have been quietly shelved.

“They have not been transparent,” then-White House press secretary Jen Psaki said of China after the release of the WHO’s initial report. “They have not provided underlying data. That certainly doesn’t qualify as cooperation."

She said the report "doesn’t lead us to any closer of an understanding or greater knowledge than we had six to nine months ago about the origin" of the virus.

Chinese officials have continued to stand behind the WHO finding.

Chinese Embassy spokesperson Liu Pengyu told ProPublica last year “the allegation of lab leaking is extremely unlikely. The conclusion should be respected. … From the very beginning, China has taken a scientific, professional, serious and responsible attitude in origins tracing.”

The official said some in the American political and media sphere “distort facts and truth” and should “stop using the epidemic for political manipulation and blame games.”

As the pandemic deepend, the blame games ratcheted up in intensity, as Republican officials continued to insist there was a shadowy truth behind the origins of Covid. In an infamous July 2021 exchange, Senator Rand Paul, alleged that Dr Anthony Fauci lied about the federal government funding research so-called “gain of function” research on novel coronaviruses in Wuhan that could’ve made them more contagious, alleging the long-time health leader was “trying to obscure responsibility for 4 million dying around the world from a pandemic”.

“Senator Paul, you do not know what you’re talking about, quite frankly, and I want to say that officially,” Dr Fauci said. “You do not know what you’re talking about.”

“You are implying that what we did was responsible for the deaths of individuals. I totally resent that,” he continued. “If anybody’s lying here, senator, it is you.”

That fall, The Intercept reported on documents showing that the National Institute of Health’s National Institute of Allergy and Infectious Diseases, headed by Dr Fauci at the time, had in fact funded a nonprofit called the EcoHealth Alliance, which partnered with the Wuhan Institute of Virology (WIV) in the past, complicating Dr Fauci’s testimony in May of 2021 that the NIH doesn’t and hadn’t funded such work.

It’s unclear whether Dr Fauci was aware of the EcoHealth Alliance work. A 2014 award to the Chinese research institute explicitly stated the money couldn’t be used for gain-of-function work, and none of the viruses listed in write-ups of the experiments performed under the grants are closely related enough to Covid-19 to spark an accidental evolution into the disease, according to The Intercept. The NIH told the news site it reviewed the nonprofit’s work and concluded that it didn’t qualify as gain-of-function research, an analysis some scientists have questioned.

Other Republican-led efforts yielded more pointed questions about Covid’s origins.

In the Senate, the committee on health, education, labour and pensions, led by then-senator Richard Burr of North Carolina, who has been recognised for his work on biodefence issues, concluded in an October 2022 report that Covid was “more likely than not, the result of a research-related incident.”

Investigators poring over opaque Chinese government reports about the lab work underway in Wuhan described a culture of intense pressure to produce prestigious scientific discoveries, mixed with worrying safety lapses and an effort to scale up the country’s bio-research apparatus before it had capacity to oversee it properly.

Ambiguous archived reports from the WIV spoke ominously of seeming references to past lab safety and biosecurity problems, describing a swift response “every time this has happened” and an urgent set of visits and communications from top Chinese government officials in the fall of 2019 surrounding some unnamed matter. Past inspections of the facility in 2011 and 2018 found issues with viral sample storage, and the Senate committee concluded that “the WIV struggled to maintain key biosafety capabilities at its high-containment BSL3 and BSL4 laboratories,” referring to a classification of labs conducting the most sensitive levels of viral research.

What’s more, a declassified US State Department fact sheet noted that the “US government has reason to believe that several researchers inside the WIV became sick in autumn 2019, before the first identified case of the outbreak, with symptoms consistent with both COVID-19 and common seasonal illnesses.”

“This raises questions about the credibility of WIV senior researcher Shi Zhengli’s public claim that there was ‘zero infection’ among the WIV’s staff and students of SARS-CoV-2 or SARS-related viruses,” according to the document.

Even ostensibly neutral attempts at finding information around Covid’s origins quickly descended into acrimony and accusations of cover-ups.

In 2022, the eminent economist Jeffrey Sachs disbanded a high-profile Lancet commission working on the origins of Covid, arguing the scientists he’d helped select for the project had conflicts of interest, accusing them of hiding their past work with the WIV and EcoHealth Alliance. (Those involved with the panel have argued they had completely normal contacts with the institute, a center of international viral research that regularly works with outside researchers, contacts that made them a better fit to serve on the investigative commission.)

Mr Sachs, meanwhile, has attracted criticism for attempting to sit in on commission-members’ sometimes sensitive interviews with Chinese researchers, and for doing a podcast interview in August of 2022 with Robert F Kennedy Jr, a leading anti-vaxxer.

Seemingly wherever any group of experts and officials got together, acrimony, doubt, and politics tended to overshadow the scientific discussion. It’s a legacy that can be felt even in the comparatively dry confines of academic journals.

In October of 2022, another group of experts published their findings on the origins of Covid in the Proceedings of the National Academy of Sciences

“Considerable scientific peer-reviewed evidence supports COVID-19’s origin as a zoonotic infection within the wildlife trade, as in many prior outbreaks,” they wrote. “While a laboratory leak cannot be ruled out, no verifiable evidence or scientific data are available to support this interpretation.”

“However, laboratory accidents do happen, and no independent formal audit of the Wuhan laboratory facilities has been possible in the wake of geopolitical conflicts,” they added.

In the face of such dispute and unceratiny, University of Washington’s Professor Cangelosi understands, in a certain way, the appeal of the lab leak theory, that a phenomenon as complex and far-reaching as the Covid pandemic could have one culprit who made a mistake in one moment. However, he cautions against using inquiries into the disease’s origins as a weapon of political blame. Instead, he said, they should be about helping us prevent future outbreaks.

“It might steer people, even people who are not politically inclined and have no ill will, it might steer them towards what they think will be a simple solution, which is shut down the labs in china,” he said. “Actually that will do nothing at all.”

Humans and animals will continue living side-by-side. Humans will continue doing research about viruses. Laboratories will continue to have issues. The key point, he said, is to take the lessons learned in this pandemic about the effectiveness of mRNA vaccines, the need for rapid and widespread viral surveillance, the crucialness of mass stockpiles of personal protective equipment, and make sure we’re ready for the next pandemic.

We may never know where this infectious disease first began, but we know for a fact it won’t be the last of its kind.