For the past three years, as international researchers have tried to solve the mystery of the origin of the coronavirus pandemic, their task has been made monumentally more difficult due to the fact that vital clues have been withheld.
On Friday, World Health Organization director-general Tedros Adhanom Ghebreyesus called out Chinese officials over samples taken three years ago at the Huanan Seafood Wholesale Market in Wuhan, asking why that data had been withheld from the rest of the world since the beginning of the outbreak.
He also demanded answers on why that data — briefly made available to international researchers earlier this year — is now missing.
The samples taken in January 2020, in the earliest days of the coronavirus outbreak, lend support to the hypothesis that the pandemic — caused by the SARS-CoV-2 virus — may have had its genesis there, where the virus may have made the jump to humans from raccoon dogs sold at the Huanan market.
“These data could have and should have been shared three years ago,” said Ghebreyesus. “We continue to call on China to be transparent in sharing data and to conduct the necessary investigations and share the results. Understanding how the pandemic began remains both a moral and scientific imperative.”
Here are some of the big questions surrounding the data:
What is a raccoon dog?
It’s neither a raccoon nor a dog … not exactly. Native to East Asia, they’re a member of the same family as dogs — Canidae — but they’re more closely related to foxes. They’re about the same size as a large fox — less than a metre in length — with short, stubby legs that, combined with their dense fur give them the shape of a large raccoon.
But they get their name from the black, raccoonlike markings on their faces.
Important to note about raccoon dogs — Nyctereutes procyonoides, for the zoology geeks — is that studies have shown they are susceptible to, and able to transmit SARS-CoV-2.
What’s the data we’re concerned about?
In late January, data was posted to the Global Initiative on Sharing Avian Influenza Data (GISAID) database — an international clearing house for researchers for sharing data on influenza and the coronavirus.
That data was posted in conjunction with a research paper later released by scientists, most from the Chinese Center for Disease Control and Prevention, which related to samples taken at the Huanan market in Wuhan in 2020.
Because a number of early COVID-19 cases had connections to the Huanan market, researchers hoped that studying samples from the market might offer some clues to where the coronavirus SARS-CoV-2 came from, and how it had been initially transmitted to humans.
The data showed the results of the analysis of 1,380 samples collected from the Huanan market in January 2020, shortly after Chinese officials shut down the market on suspicions it might have been linked to the coronavirus outbreak. Of those, 73 samples tested positive for SARS-CoV-2.
What happened to the data?
The data from the January 2020 samples was posted on GISAID in late January 2023, shortly before the Chinese research was released.
While that data was online, researchers from a number of countries downloaded it in order to do their own analyses.
At some point shortly after that, the data disappeared from GISAID.
When the WHO reached out to the Chinese research team regarding the disappearance, they were told that the data had been restricted to allow updates, pending an update of the research paper itself.
The WHO asked the researchers from the Chinese CDC and from the international group of scientists to each present their analyses of the data to its Scientific Advisory Group for the Origins of Novel Pathogens (SAGO), which they did on March 14.
Why is the missing data so concerning?
There are two problems here. One is that the samples were taken by Chinese researchers in early January 2020, but that data was only recently shared with the rest of the world.
That means that for the past three years, outside of China, researchers trying to solve the puzzle of the origin of the pandemic have been doing so with one hand tied behind their backs.
Mike Ryan, executive director of WHO’s Health Emergencies Programme, likened solving the coronavirus origin mystery to trying to solve a jigsaw puzzle without ever seeing the actual picture of the finished product on the box cover.
“You know that the more pieces you have in the right place, the more you start to see an image,” he said.
“But you’re never really sure of what you’re building. You’re never sure what one piece does until you put the piece in the context of all of the other pieces, and then a picture starts to grow and your level of confidence as to what that picture is grows as you put more pieces in the right place.”
For three years, global researchers had been trying to build this picture with puzzle pieces missing from what might have been the epicentre of the pandemic. And until the data from the samples taken at Huanan market was uploaded in late January, they didn’t know those puzzle pieces existed.
The other problem is that the Chinese data, uploaded to GISAID in late January, was, shortly thereafter, taken down, making it inaccessible to scientists seeking to perform their own analyses on the Huanan market samples. (Some scientists around the world downloaded the data while it was still accessible).
“The big issue now is that this data exists and that it is not readily available to the international community,” said WHO’s COVID-19 technical lead Maria Van Kerkhove at the briefing.
“The challenge that we have is that there is data that is out there, that exists, that has not been made available to us, that has not been made available to the SAGO and has not been made available to the international community.”
“And until we have that information, we won’t be able to remove different hypotheses.”
What does the data tell us?
To start with, there is no smoking gun here.
Scientists already knew from last year that there were samples from the Huanan market that tested positive for SARS-CoV-2.
What they learned with the new data was that animals were sold at that market, and that, among the 73 samples from January 2020 that tested positive for SARS-CoV-2, there was DNA evidence that identified some of those animals.
Among those animals that were identified by DNA traces was the raccoon dog, an animal previously known to scientists to be susceptible to SARS-CoV-2.
Though it’s consistent with the idea that the Huanan market was Ground Zero for the pandemic and that the virus jumped from raccoon dog to man, the evidence, as it stands, is circumstantial.
Although the samples show traces of the coronavirus and of raccoon dog DNA, we don’t know if those traces were deposited at the same time. We don’t know if the raccoon dogs whose DNA traces we find were infected with the virus. And we don’t know — if they were infected — if the virus then made the jump from raccoon dog to man. It’s possible that a raccoon dog could have been infected by another animal, or a human.
But the samples, and the data from them, give scientists more leads to follow. And it will likely allow them to narrow the field by eliminating some hypotheses.
“We need to make clear that the virus has not been identified in an animal in the market or in animal samples from the market, nor have we actually found the animals that infected humans,” said Van Kerkhove.
“What this does is provides clues to help us understand what may have happened.”
Where do those clues lead scientists?
The WHO has been asking the Chinese scientists to follow the path upstream, so to speak, to start looking at the origins of those animals that were in the market in Wuhan and trace them back to the farms from which they came.
Doing so might give researchers clues as to how those animals came to be in the Huanan market, whether they were infected when they got there, or whether that may or may not have happened afterward.
“Were these animals traded? Were they wild animals or domestic animals? Were they farmed? Where were they farmed?” asked Van Kerkhove.
“We have repeatedly asked for studies to be done in other markets in Wuhan and in Hubei and across China. We have repeatedly asked for studies to trace those animals back to their source farms so that we can go back in time and actually look to see where the animals came from and if any testing had been done.”
If they can get that kind of data, if it is shared so they can collaborate on the analysis, scientists might find themselves one step closer to solving the mystery of the origin of the pandemic. And potentially closer to mitigating future ones.