There is a new review of potential SARS-CoV-2 origins. Here’s what the experts think

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As the world goes through a horrific phase of 4 million deaths from COVID-19, and new viral variants wreak havoc in unvaccinated communities, the debate continues over the question of whether SARS-CoV-2 leaked from a research facility.

Now a group of scientists – including the world’s leading virologists and Nobel laureates – have risen to the challenge by critically reviewing the scientific evidence to date, concluding that there is currently no evidence that the virus that causes COVID-19 from laboratory.

“Our careful and critical analysis of the data currently available has not provided any evidence for the idea that SARS-CoV-2 originated in the laboratory,” says virologist and lead author Edward Holmes, who worked before this pandemic on the viruses that caused the Ebola outbreak. and influenza epidemics.

Knowing that a laboratory breach cannot be completely ruled out, the group summarizes the evidence for the natural origins of SARS-CoV-2 and argues that human activities, such as deforestation and the wildlife trade, have “repeatedly put us on a collision course with new viruses.”

They also cautioned that focusing on a highly unlikely laboratory origin distracts from more pressing scientific tasks, such as researching animal sources for SARS-CoV-2, or preparing for the next pandemic — as we should have done for this one.

“The current preliminary version provides a clear and logical description of the viral events that occurred during the emergence of the pandemic virus,” says virologist Jonathan Stowe of the Francis Crick Institute, who was not involved in the review.

Evidence in favor of SARS-CoV-2’s animal origins has been found in closely related viruses detected in bats and pangolins, and through people interacting with those animals.

The review, which is available as an introduction to print and is subject to peer review, also cites other evidence inconsistent with the in vitro leak theory: SARS-CoV-2 is unable to infect lab mice, and is a preferred animal model for the study. Viral infection.

And if someone artificially engineered the virus in a lab, there would be genetic markers for that process in the SARS-CoV-2 sequence — which could never be found.

“[The review] It makes a strong case for the natural origin of the virus followed by continued adaptation in humans,” says Stowe.

While many of the early documented cases of COVID-19 have been linked to the now-closed Wuhan wet market, in the end it was “a more amplified event than necessarily true ground zero. So we need to look elsewhere for viral origins,” public health researcher Dominic wrote. Dwyer, who was part of the WHO’s investigation into Wuhan, in February.

However, as the new review makes clear, there is still no epidemiological evidence linking SARS-CoV-2 – or its possible precursor – to the Wuhan Institute of Virology, where researchers study bat-borne coronaviruses.

“The main source may have been an infected agent who may have taken it home after being infected in the lab,” says Stuart Turville, a virologist at the Kirby Institute in Sydney, Australia. “However, this has not been documented in any early indicator cases.”

Despite the comprehensiveness of the recent review, the “laboratory leak” scenario cannot be conclusively ruled out, leaving room for doubts to creep in. Even the WHO investigation was inconclusive.

“No single research journey can provide all the answers,” WHO Director-General Tedros Adhanom Ghebreyesus said in March of this year, when the WHO released its first report detailing its extensive investigation into the origins of SARS-CoV-2. “.

On the whole, experts currently agree that the most likely scenario is that the virus was circulating in wild animals, then spread to human contacts, and then evolved naturally to adapt to its most recent host.

However, immunologist Nikolai Petrovsky of Flinders University in Australia is less certain, saying the new analysis provides “the least conclusive evidence” and no strong conclusions.

“The actual origins of the virus remain a pretty open judgment split between an indirect natural event from an as-yet-unidentified animal vector, or a laboratory accident,” Petrovsky says.

“Based on the actual knowledge so far, no possibility can be proven or refuted definitively.”

Other experts are more supportive of the review and its findings. Infectious disease epidemiologist James Wood at Cambridge University says:

“They took into account the uncertainties that always existed about retrospective investigations of this kind, and also noted that a laboratory accident could not be completely ruled out, but that this is highly unlikely for an origin that involves human and animal contact. “

The team argues that the historical record of other so-called zoonotic viruses that have jumped from animals to humans, is additional evidence supporting the animal origins of SARS-CoV-2.

“All previous human coronaviruses have animal origins, as do the vast majority of human viruses,” they wrote before acknowledging that the animal source of the coronavirus may never be found, which has given wind to the laboratory leakage theory in the first place.

In fact, the animal origins of many known human pathogens, including Ebola virus, hepatitis C virus, polio virus, and [other] The group wrote that coronaviruses … have not yet been identified.

There are few things for sure though: Conspiracy theories and rumors are very dangerous, even deadly, and we must learn from this pandemic to protect ourselves for the next.

The review is available on the Zenodo prepress server.

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