COVID-19: Why we’re looking for the pandemic’s origin – DW (English)

Four years after the COVID-19 pandemic provoked whole countries into lockdown, scientists are still trying to find conclusive evidence to pinpointwhere the virus first infected humans.

But does it really matter whereSARS-CoV-2, the virus that caused COVID,originated now that life's back to a kind of normal? What's the difference if the virus leaked from a lab or developed in nature?

Well, researchers say it does matter: They say it's one of the most important questions for our understanding of how pandemics start and how we can prevent them in the future.

The answer, they say, would have a lasting effect on health policy, scientific funding, public opinion on science, and diplomatic relations.

Not to mention the fact we're still living with COVID:The World Health Organization (WHO) COVID-19 Dashboard continues to reporthundreds of thousands of cases every month worldwide.

But from lab leak theory to zoonotic theory, and conspiracy theories in between, there's no consensus on COVID's origin.

With new investigations and analyses emerging on this fourth anniversary, we take a look at the current thinking.

Arguments for the lab leak theory center around the Wuhan Institute of Virology , aninstitute where scientists were researching coronaviruses at the time of the initial outbreak in China.

"The strongest evidence comes from the timeline of research [going back to] 2012. Published papers from the institute show scientists could construct modified coronaviruses," said Richard H. Ebright, a professor of chemical biology at Rutgers University in theUS.

Research included genetically altering coronaviruses to make them stronger such asadding spike proteinsand testing the viruses' ability to spread. Their stated aim was to help prevent coronavirus outbreaks.

But we don't know how many coronaviruses the institute studied. "They refused to collaborate from the start," opined Ebright.

Some experts say it's possible that the Wuhan lab had progenitor strains ancestorsof SARS-CoV-2, butChina's alleged withholding information on the origin of COVID makes this impossible to prove or disprove.

Then there's the question of how the virus would have leaked.Some say it leaked by accident, due to weak security measures at the lab, and other suggest it was intentionally developed and released as a biological weapon. But there is no firm evidence for either theory.

"Every form of the lab leak theory involves some sort of cover up, which to me means that it's a conspiracy theory," said Edward Holmes, a professor of virology at the University of Sydney inAustralia.

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Some scientists prefer the zoonotic theory: The theory that the virus evolved in nature from an existing coronavirus and spread from wild animals to humans at theHuanan Seafood Wholesale Market, also in Wuhan, China.

Researchers said they had analyzed statistical data to locate what they said were the first human cases and that those cases were among market vendors who sold live animals.

"The evidencesupports a zoonotic origin," said Angie Rasmussen, a virologist at the University of Saskatchewan in Canada."It includes detailed studies of SARS-CoV-2 [...] and its evolutionary trajectory once [it was in]the human population."

Scientists havestudied samples from wild animals in Wuhan for signs of the original SARS-CoV-2 virus. But they have failed to find it. And they have also failed to trace how the virus spread from the market to the outside environment.

"The key step of tracing and testing the animals at the Huanan marketwas not done [at the time] and it's too late now. For this reason, we have been unable to identify the exact animal ancestry," said Holmes.

But given that Huanan market is 16 kilometers (10 miles) from the Wuhan Institute of Virology, some people continue to suggests thatthe lab and/or the market were COVID's epicenter.

Anexpert survey in February 2024 found that most scientists believe COVID emerged from nature.

The expert respondents gave the natural, zoonotic (or zoonosis) theory an average likelihood of 77% four out of five of the experts said it was more than 50% likely. But the experts said there wasa 21% likelihood that COVID started due to "research-related accident" one out of five of the experts said there was a 50% or greater chance of that.

"When you takeother intelligence into account,the lab leak theory starts to seem more plausible," said Seth Baumof the Global Catastrophic Risk Institute, which co-published the survey with Nemesys Insights.

When Baum refers to "other intelligence," he's talking about non-scientificfactors, such as proximity of the market to the lab.

Much of the evidence that might provide a conclusive answer, however, has been lostor remains unavailable for public scrutiny.

"Whether we'll get an evidence-based conclusion depends on countries like China collaborating and being forthcoming with data," said Baum.

The one thing experts do agree on is that we need to keep trying to solvethe mystery of COVID's origin it may determine how werespond to nextpandemic.

Edited by: Zulfikar Abbany

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COVID-19: Why we're looking for the pandemic's origin - DW (English)