The Covid Lab leak theory is dead. Here’s how we know the virus came from a market in Wuhan

By PTI IST (Released)


Huanan Market was the epicenter of the pandemic. An analysis of the geographic locations of the earliest known COVID cases dating back to December 2019 revealed strong clustering around the Huanan market.

My colleagues and I published the most detailed studies of the early events of the COVID-19 pandemic last month in the journal Science.

Together, these documents paint a cohesive, evidence-based picture of what happened in the city of Wuhan during the latter part of 2019.

The take-home message is that the COVID pandemic likely started where the first cases were detected at the Huanan Seafood Wholesale Market. At the same time, it puts an end to the idea that the virus escaped from a laboratory.

Huanan Market was the epicenter of the pandemic

An analysis of the geographic locations of the earliest known COVID cases dating back to December 2019 revealed strong clustering around the Huanan market.

This was true not only for people who worked or visited the market, but also for those who had no connection to it. Although there are many missing cases, there is no evidence of widespread sampling bias: the first COVID cases were not identified simply because they were linked to the Huanan market.

Huanan Market was the epicenter of the pandemic. From its origin there, the SARS-CoV-2 virus quickly spread to other places in Wuhan in early 2020 and then to the rest of the world.

Huanan Market is an indoor space the size of two football fields. The word seafood in its name leaves a misleading impression of its function. When I visited the market in 2014, a variety of live wild animals were for sale, including raccoon dogs and muskrats.

At the time, I proposed to my Chinese colleagues to take viruses from these market animals. Instead, they set up a virological surveillance study at nearby Wuhan Central Hospital, which then treated many of the first COVID patients.

Wild animals were also for sale in the Huanan market in 2019. After the market was closed by Chinese authorities on January 1, 2020, investigation teams took surfaces, door handles, pipes, frozen animals , etc.

Most of the samples that later tested positive for SARS-CoV-2 came from the southwest corner of the market. The wildlife I saw for sale when I visited in 2014 was in the southwest corner. This establishes a simple and plausible pathway for the virus to jump from animals to humans.

animal overflow

SARS-CoV-2 has evolved into an array of lineages, some of which are familiar to us as variants of concern (what we call Delta, Omicron, etc.).

The first split in the SARS-CoV-2 family tree between lineages A and B occurred very early in the pandemic. Both lineages have an epicenter at the market and both have been detected there.

Further analyzes suggest that lineages A and B were the products of separate jumping animals. It just means that there was a pool of infected animals in the Huanan market, fueling multiple exhibition events.

Reconstruction of the history of mutations in the SARS-CoV-2 genome sequence through time showed that lineage B was the first to jump to humans. It was followed, perhaps a few weeks later, by the A line.

All of these events are believed to have occurred no earlier than the end of October 2019. Claims that the virus was spreading before this date can be dismissed.

What is missing, of course, is that we don’t yet know exactly which animals were involved in transferring SARS-CoV-2 to humans. Live wild animals were removed from the Huanan market before the investigation team entered, increasing public safety but hampering the original hunt.

The opportunity to find the direct animal host has probably passed. As the virus probably spread rapidly through its animal reservoir, it is too optimistic to think that it would still be circulating in these animals today.

The lack of a definitive animal source has been seen as tacit support for counter-claims that SARS-CoV-2 actually leaked from a science lab at the Wuhan Institute of Virology.

The death knell of the laboratory leak theory

The lab leak theory rests on an unfortunate coincidence: that SARS-CoV-2 appeared in a town with a lab that works on bat coronaviruses.

Some of these bat coronaviruses are closely related to SARS-CoV-2. But not close enough to be direct ancestors.

Unfortunately, the focus on the Wuhan Institute of Virology has distracted us from a much more important link: that, like SARS-CoV-1 (which emerged in late 2002) before it, there is a direct link between a coronavirus epidemic and a living animal. market.

Consider the odds that a virus that escaped from a lab was first detected in the very place you would expect it to emerge if it actually had an extremely low natural animal origin .

And those odds drop further because we have to connect the A and B lines to the market. Was the market just the location of a superspreader event? Nothing says it. It was not a crowded place in the bustling, globally connected metropolis of Wuhan. It’s not even close to being the busiest market or mall in town.

For the lab leak theory to be true, SARS-CoV-2 must have been present at the Wuhan Institute of Virology before the pandemic began. That would convince me. But the inconvenient truth is that there is not a single piece of data to suggest this.

There is no evidence of a genome sequence or isolate of a precursor virus at the Wuhan Institute of Virology. Not from genetic sequence databases, scientific publications, annual reports, student theses, social media or email.

Even the intelligence community found nothing. Nothing. And there was no reason to keep work on a SARS-CoV-2 ancestor secret before the pandemic.

Attributing the origin of SARS-CoV-2 to the Wuhan Institute of Virology requires a set of increasingly implausible scenarios what if? scenarios. These eventually lead to absurd suggestions of clandestine bioweapons research.

The lab leak theory presents itself as a tamper-proof claim. If an investigation of the lab turned up no evidence of a leak, the scientists involved would simply be accused of hiding the relevant material.

If it’s not a conspiracy theory, it’s a theory requiring a conspiracy. It provides a convenient vehicle for calls to limit, if not outright ban, gain-of-function research in which viruses with vastly different properties are created in the laboratory. Whether or not SARS-CoV-2 originated this way is incidental.

Wounds that may never heal

The acrid stench of xenophobia lingers over much of this discussion. The staunch rejections by Chinese scientists of anything untoward are blithely presented as lies. Yet during this crucial period, these same scientists traveled to international conferences and welcomed visitors.

Do we honestly believe they would have such pathological disdain for the consequences of their actions? The debate over the origins of COVID has opened up wounds that may never be healed. It has armed a distrust of science and fueled a divisive political opinion. Individual scientists have been assigned the sins of their governments.

The relentless blame game and finger pointing further reduced the chances of finding viral origins. History will not judge this period kindly. Global collaboration is the foundation of effective pandemic prevention, but we risk destroying rather than building relationships.

We may even be less prepared for a pandemic than in 2019. Despite salivating political and media barriers, evidence of a natural animal origin for SARS-CoV-2 has multiplied over the past two years. . Denying it puts us all in danger.


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