Origin of coronavirus pandemic remains unclear: US intelligence report

US Director of National Intelligence Avril Haines submitted a report on the origins of the SARS-CoV-2 coronavirus to President Joe Biden on Tuesday (August 24, 2021). The following day marked the end of a 90-day deadline Biden had set for U.S. intelligence agencies to gather everything they could find about where the pandemic originated.

While the report is still under seal, two unnamed government officials told The Washington Post that the report did not reach a final conclusion. According to them, there wasn't even agreement within the US intelligence community. Two different agencies came to two different conclusions: One suspects that the virus was passed from an animal to a human, while the other assumes that the first infection of a human happened through a laboratory accident.    

Here is an overview of what was already publicly known before the intelligence report:

Since SARS-CoV-2 became known to the world in early 2020, nearly 214 million people worldwide have been infected with it. Almost 4.5 million people have died from or with the virus. And the pandemic has crippled economies for months on end. But where did this highly contagious virus come from? So far, there is more conjecture than fact as to where the global pandemic originated.

In May 2021, the Wall Street Journal reported on a possible accident at the Institute of Virology in Wuhan, citing an earlier unpublished US intelligence report.

It said that in November 2019, three employees at the institute fell so seriously ill with COVID-like symptoms that they had to be treated in a clinic. China denied this. It was as a consequence of this that US President Joe Biden ordered the intelligence community on May 27 to gather reliable facts rather than speculation about a possible lab accident.

"The US will continue to work with like-minded partners to pressure China to participate in a full, transparent, fact-based international investigation and provide access to all relevant data and evidence," Biden said.

China, however, accused the US of trying to politicize the search and blame China for the pandemic. At the same time, Beijing is blocking an open-ended investigation and categorically rejects any responsibility on principle.

What is known about the virus?

As early as January 2020, Chinese scientists found the cause for a cluster of a previously unknown pneumonia infections that had killed a surprisingly high number of people in the city of Wuhan. They found the genes of a positive-stranded RNA virus from the coronavirus family in respiratory cells of the patients. The researchers could intentify the virus as belonging to subgroup B (betacoronavirus).

This virus was definitely completely new, but had great similarities to the coronavirus that had caused the SARS pandemic between 2002-2004, also named SARS-CoV-1. Starting in southern China, that previous virus had spread to almost all continents within a few weeks. Worldwide, 8,096 people were diagnosed with severe acute respiratory syndrome (SARS) and 774 died.

Even though the number of cases was low compared to the current SARS-CoV-2 pandemic, it was already demonstrated at the time how frighteningly quickly a highly infectious disease can spread in a globalized world.

Where was the virus first discovered?

Some studies suggest that the new SARS-CoV-2 virus had been spreading for several weeks or even months before it was discovered in Wuhan in late December 2019.

In China, according to the South China Morning Post, there had already been a first confirmed infection with SARS-CoV-2 in mid-November.  However, this does not mean that the virus necessarily originated in China.

Researchers at the University of Cambridge had published a study in April 2020 suggesting that the pandemic most likely began between September and early December 2019 ? either in China or a neighboring country.

But traces of the novel pathogen were also found in stored wastewater samples from Brazil and Italy that had already been collected in November and December 2019, respectively. In Italy, antibodies to SARS-CoV-2 were also found in blood samples from participants in a lung cancer screening program.  Astonishingly, some of the blood samples had already been collected in September 2019, others in February 2020. There was some uncertainty about the findings, however.

The fact that the virus was already detected sporadically in Europe in the late fall of 2019 and in China from mid-November does not allow any reliable conclusions to be drawn about the origin of the pandemic. It merely shows how quickly a highly aggressive virus can spread across the world.

From which animal did the virus originate?

The most likely scenario is a zoological origin via an intermediate host.  That would mean some animal carried the original virus, then passed it on to another animal and that animal passed it to the first human. So far, however, neither the potential source animal nor the intermediate host has been identified beyond a doubt. The two SARS coronaviruses have not yet been clearly identified in animals either.

However, the two SARS viruses are definitely related to coronaviruses found in certain bat species found in Southeast Asia. In addition, studies have traced previous epidemics involving coronaviruses such as SARS and Middle Eastern Respiratory Syndrome (MERS) to bats as well.

The gene sequence of the current SARS-CoV-2 is a 96.2% match with coronavirus RaTG13, which was previously found in a horseshoe bat.

More than 96% sounds like a lot, but it is only a first indication. This is because even the match with, for example, a coronavirus detected in pangolins is only slightly lower.

Since most people do not normally have direct contact with horseshoe bats or pangolins, the experts are also investigating potential intermediate hosts that are in closer contact with humans, such as minks, martens and civets.  Minks for example can catch SARS-CoV-2 from humans comparatively easily. A transmission from animals to humans is less likely, but possible.

Berlin virologist Christian Drosten also believes an origin of SARS-CoV-2 in the fur industry is the most plausible explanation.

"I don't have any evidence for that, except the clearly proven origin of SARS-CoV-1, and this is a virus of the same species. Viruses of the same species do the same things and often have the same origin," Drosten told the Swiss online magazine Republik.

With the first SARS virus, the transitional hosts were racoon dogs and Viverridae, Drosten said. "That's backed up by science."

In China, racoon dogs are still used in the fur industry on a large scale, Drosten says. He explains that wild racoon dogs are repeatedly brought into breeding operations. And these animals may have previously eaten bats ? considered the most likely source of Sars-CoV-2.

"Racoon dogs and Viverridae are often skinned while they are still alive," the Charité virologist explained. They emit death cries, and roar, and aerosols are produced in the process. That's how humans can become infected with the virus.

For him, he said, it was surprising to see that this form of breeding would still come into play again as a possible starting point for a pandemic. Until recently, he had mistakenly believed, "somewhat naively," he admitted, that authorities had introduced stiffer controls on the breeding of species with a known potential as transitional hosts.

"To me, that story was closed and done. I thought that this kind of animal trafficking had been stopped and that it would never come back. And now SARS has come back."

Drosten acknowledged that there is no concrete evidence yet that the transition to humans occurred through fur farms. There have been no studies in this area at all, at least none have become public, he said.

Did the virus come from a laboratory?

Evidence shows that the Wuhan Institute of Virology experimented with the coronavirus RaTG13 and with RmYN02, whose gene sequence is 93.3% identical to SARS-CoV-2.  That means there are two unproven scenarios: SARS-CoV-2 could have been either artificially created as a type of bioweapon and/or released by accident.

The WHO experts sent to China consider both scenarios "extremely unlikely." However, they were not really able to gather convincing evidence to dismiss the theories outright either. During their very limited investigation in early 2021, about a year after the start of the pandemic, they could not conduct their own inspections or evidence gathering; China did not allow that.

Instead, they had to rely on publicly available data and information from their Chinese interlocutors. After the trip, even WHO chief Tedros Adhanom Ghebreyesus demanded to at least further examine the hypothesis of a laboratory accident in Wuhan.

What is the evidence for a biological weapon?

Most experts consider the artificial generation of SARS-CoV-2 in a research lab in Wuhan to be highly unlikely. A team led by Swedish microbiology professor Kristian Andersen of the Scripps Research Institute in La Jolla, California, studied primarily the prominent spike proteins on the virus surface, where the virus docks to a host cell in the lungs or throat to invade it.

Genome sequencing revealed two significant differences between SARS-CoV-2 and its corona relatives. The protein is structured differently and the amino acids are composed differently. While this may make it easier for the SARS-CoV-2 virus to infect human cells, the virus structure is not sophisticated enough for a "biological weapon," according to the La Jolla team.

Drosten, the virologist from Berlin, also considers it "extremely unlikely" that the virus originated in a laboratory. "If someone had developed SARS-CoV-2 like this, I would say they did it in a pretty untargeted way."

With the first SARS virus as a basis, Drosten said, researchers would have been more likely to change only very specific characteristics for research purposes. SARS-CoV-2, however, is full of deviations from the first virus, he explained, indicating that those likely developed as part of a natural process.

What speaks for a laboratory accident?

The theory that the Chinese researchers experimented with the dangerous coronaviruses such as RaTG13 or RmYN02 and that SARS-CoV-2 was released by accident remains. Chinese leadership categorically rules this out.

The WHO experts sent to China also classify such an accident as "extremely unlikely," on the basis of the data available to them. Among other things, the evolution of the virus speaks against this. In addition, the Wuhan Institute of Virology uses appropriate high-security laboratories.  And there are no indications of laboratory accidents or suspicious illnesses among employees in the data shared with the WHO investigators.

But the data don't seem to tell the whole truth, according to the US. intelligence report cited by the Wall Street Journal. There was no mention of the three employees of the institute who in November 2019 reportedly fell so severely ill with COVID-like symptoms that they had to be treated in a clinic. Then again, China claims that never happened.