Understanding the Covid-19 Lab-Leak Theory

After more than a year of scientific hypotheses, baseless conspiracy theories, and a lack of transparency from China, we still don’t know Covid-19’s origin story — the precise route SARS-CoV-2 took to end up as the cause of a global pandemic. And thanks to the country’s deep partisan divides, even the suggestion that we still need a clearer picture of how the novel coronavirus got its start can be perceived as politically charged.

So on May 26th, when President Joe Biden issued a statement on his request that the intelligence community “redouble their efforts to collect and analyze information” to learn more about the origins of Covid-19, it prompted a range of reactions. For those who’ve spent the past 15 months following the science of the pandemic — including the presumed consensus that SARS-CoV-2 was first transmitted to humans via animals — the president’s announcement was jarring.

That’s because the other plausible theory of transmission, that the novel coronavirus was accidentally leaked from a lab, was the position backed by former President Donald Trump, and, as a result, many of his followers. But, like the virus itself, Trump’s stance mutated, then promptly spread amongst his supporters.

What started as a science-based hypothesis, had, in Trump’s hands, morphed into an attempt to blame everything on China, firmly rooted in anti-Asian racism. Evidence became irrelevant — except in April 2020, when he claimed to have some supporting a lab leak, although he “wasn’t allowed” to talk about it, and his own intelligence agencies said it didn’t exist.

By that point, Trump’s conspiracy theorist followers were off and running. And so, despite their vast differences, those advocating for more thorough scientific research into the possibility of an unintentional lab leak, and right-wing conspiracy peddlers ended up being lumped together, and, at times, conflated.

What’s happened since has been an example of the complicated relationship between science and politics, and how a typically routine aspect of a viral outbreak investigation has become distorted to the point where even those who have stood firmly on the side of science and reason are questioning the motive. Here’s what we know, don’t know, and hope to find out about the origins of Covid-19.

Two Separate but Unequal Theories

Like the pandemic itself, the attention given to the origin of Covid-19 has come in waves. When SARS-CoV-2 first started to spread, there were immediate questions about how this virus infected humans for the first time.

Based on existing knowledge of other coronaviruses, most scientists backed the hypothesis that SARS-CoV-2 was spread through “natural spillover” — meaning that a virus was able to overcome the usual hurdles that prevent it from transmitting from one species to another (in this case, humans). The first confirmed cases of what we now know as Covid-19 were initially linked to markets in the Chinese city of Wuhan, where animals are sold both dead and alive.

There was also a competing theory: That the virus spread following an accidental release from a lab — specifically, the Wuhan Institute of Virology, where researchers study multiple strains of coronaviruses. Proponents of this explanation, including Trump, argue that it’s too much of a coincidence that the virus was first detected in markets in the same city that hosts a lab that studied  the same type of virus. But, as the New York Times reports, “Wuhan is an urban center larger than New York City” with animal-market traffic from throughout China and the rest of the world — so it’s entirely possible that it is a coincidence.  

Like the natural spillover theory, what’s come to be known as the “lab leak” theory is also based on scientists’ prior experience with coronaviruses, according to Dr. Amesh Adalja, senior scholar at the Johns Hopkins University Center for Health Security.

“Anytime there’s an infectious disease outbreak, it is really important to ensure that it’s not an accidental lab-leak, because we know that there are labs all around the world using or working with viruses that pose threats to human health,” he tells Rolling Stone, citing previous examples of this happening — including during the SARS outbreak in 2004. “We’ve seen lab accidents all over, where a laboratory worker gets infected inadvertently, they don’t know about it, and, if it’s a contagious disease, they may spread in the community. That, I think, was something everybody never fully discounted.”

What scientists and other infectious disease experts quickly discounted, however, was the notion that the novel coronavirus was engineered or intentionally released. “I don’t think anybody believed this to be a biological weapon — especially when you have to do so much damage to the Chinese people themselves,” Adalja says. “Also, there was no evidence that this was an engineered virus.” 

A Need for Answers 

Like most scientists, Dr. Peter Hotez, co-director of the Center for Vaccine Development at Texas Children’s Hospital and dean of the National School of Tropical Medicine at Baylor College of Medicine, continues to “favor the natural-origins hypothesis,” based on the evidence that is currently publicly available. “There’s no smoking gun saying that it either was synthetically made in the laboratory in any way, or leaked — and it’s certainly possible — but I don’t see anything that’s really compelling that makes me think that,” he explains. 

In fact, Hotez, author of Preventing the Next Pandemic: Vaccine Diplomacy in a Time of Anti-science, says that the only way we’ll have any answers to our questions about the origins of Covid-19 “is through a pretty extensive on-the-ground investigation.” Along the same lines, Adalja — who has supported doing a thorough and independent review of the lab-leak hypothesis since the pandemic began — says that it would have a significant value from a public health standpoint. 

“We still don’t understand how [SARS-CoV-2] made its way from bats into some intermediate animal, or into humans, and I think unraveling that is really important,” he explains “Once people realized the first SARS came from palm civet cats, it basically disappeared, because they started handling those animals very differently. So, from that sense, I think that there is a public health importance to understanding the origin of the virus and understanding viral emergence.”

But despite the potential widespread benefits of the findings of this type of investigation — including looking into whether the outbreak involved an accidental lab-leak — many of the scientists who saw the merit of this approach fell silent. That’s because anything to do with the lab-leak theory was inextricably linked with Trump, his followers, and their campaign of misinformation and conspiracy theories: an association no credible scientist wanted. 

Why Now?

So why has the lab-leak hypothesis resurfaced now and received so much attention? It began on March 30th, 2021, with the release of a long-awaited report from the World Health Organization (WHO) into the origins of the pandemic. In it, the investigators — a team of 17 experts from China and an additional 17 from other countries — asserted that they found no conclusive evidence of either a natural spillover or lab leak. 

However, based on their assessment, the team indicated that it was “likely to very likely” that the first humans were infected with SARS-CoV-2 via animal transmission involving an intermediate host (e.g. transmitted from bats to another animal to humans), and that a lab accident was “extremely unlikely.” Still, given the lack of direct evidence, the team noted that further studies are needed before any solid conclusions can be drawn.

On the day the report was published, WHO Director-General Dr. Tedros Adhanom Ghebreyesus — who was not directly involved with the investigation — echoed the team’s sentiments about more work needing to be done, and also expressed frustration over China’s lack of cooperation and transparency during the process, including sharing crucial raw data. He also remarked that he didn’t think that the team’s assessment of a potential lab accident “was extensive enough,” and offered to support further research.

Then, on May 14th, a group of 18 well-respected scientists from North America and Europe published a letter in the journal Science, agreeing with Tedros that the accidental lab leak hypothesis wasn’t given balanced consideration in the WHO report, and that further investigation into the origins of the virus is “necessary and feasible to achieve.” Two weeks later, Biden made the request for a renewed investigation, and almost immediately a spokesperson from the Chinese Embassy in the U.S. issued a statement referring to Biden’s request as “the old trick of political hype” and a “smear campaign.” From here, the conversation escalated quickly.

Reexamining the Lab-Leak Theory

Shortly before leaving office in January 2021, former Secretary of State Mike Pompeo released a fact sheet containing possible evidence of an accidental lab leak, including that the “U.S. government has reason to believe that several researchers inside the W.I.V. became sick in autumn 2019, before the first identified case of the outbreak, with symptoms consistent with both Covid-19 and common seasonal illnesses.”

Then, on Sunday, May 23rd, the Wall Street Journal reported that according to previously undisclosed intelligence information, three researchers from the Wuhan lab who fell ill with Covid-like symptoms in November 2019 — referenced in Pompeo’s fact sheet — were treated in a hospital. While that article reignited interest in the lab-leak theory, CNN poured on the gasoline two days later when it reported that late into the Trump administration, Biden had shut down Pompeo’s probe into the origins of Covid-19, because he did not see the findings as legitimate.

Given the renewed interest in thoroughly investigating the lab-leak theory, Republicans swiftly criticized the Biden administration for putting a stop to what could have been a useful inquiry. And right on cue, Trump claimed it as a victory. “Now everybody is agreeing that I was right when I very early on called Wuhan as the source of COVID-19, sometimes referred to as the China Virus,” he wrote on his blog on May 25th. “To me it was obvious from the beginning but I was badly criticized, as usual. Now they are all saying ‘He was right.’” 

The following day, Biden issued a statement about his plans for a more comprehensive intelligence investigation — and the reaction was immediate. For the first 24 hours following Biden’s announcement, the public wasn’t aware that the White House had received what the New York Times described as “a raft of still-unexamined evidence” that could potentially contain clues about the origins of SARS-CoV-2. 

Prior to learning that it was new evidence that sparked Biden’s investigation, many saw the move as the president granting legitimacy to everything from conspiracy theories involving bioweapons, to the anti-Asian racism Trump slung alongside his accusations that China was allowing SARS-CoV-2 to spread after a lab leak. 

But in reality, Dr. Matthew M. Kavanagh, director of the Global Health Policy & Politics Initiative at Georgetown University, says that Biden’s call to “redouble” the investigation aligns with the WHO’s report from March, as well as the request from Tedros for additional research into the accidental lab-leak theory. Meanwhile, Adalja and Hotez both welcome a more extensive review, though aren’t necessarily convinced that the focus on intelligence will produce the most useful results. 

“We don’t need an intelligence report, we need an outbreak investigation — and that’s a very different skill set, and a very different approach,” Hotez explains, noting that it would take between six and 12 months to complete. “There’s going to be a Covid-26 and a Covid-32 — it’s inevitable. And if we’re going to learn how to start controlling these things, we really need to do a deep dive to understand how this happened.”

Kavanaugh agrees, noting that if the aim of Biden’s report was finding a scientific explanation of the origins of Covid-19, he would have tasked the CDC or NIH with it, instead of U.S. intelligence agencies. “This tells us that this is a political and an intelligence story: not a story mostly about science,” he says. “And so we should understand the picture in that sense, and not be naive about it. We’re in a place where politics is driving people’s scientific understanding in a dangerous way.”