Covid-19 origins: WHO addresses new proof from China
There’s a tantalizing new clue within the hunt for the origins of the Covid-19 pandemic.
A brand new evaluation of genetic materials collected from January to March 2020 on the Huanan Seafood Market in Wuhan, China, has uncovered animal DNA in samples already recognized to be optimistic for SARS-CoV-2, the coronavirus that causes Covid-19. A big quantity of that DNA seems to belong to animals generally known as raccoon canine, which had been recognized to be traded on the market, in accordance with officers with the World Health Organization, who addressed the brand new proof in a information briefing on Friday.
The connection to raccoon canine got here to mild after Chinese researchers shared uncooked genetic sequences taken from swabbed specimens collected on the market early within the pandemic. The sequences had been uploaded in late January 2023, to the information sharing website GISAID, however have just lately been eliminated.
An worldwide group of researchers observed them and downloaded them for additional research, the WHO officers mentioned Friday.
The new findings – which haven’t but been publicly posted – don’t settle the query of how the pandemic began. They don’t show that raccoon canine had been contaminated with SARS-CoV-2, nor do they show that raccoon canine had been the animals that first contaminated individuals.
But as a result of viruses don’t survive within the surroundings exterior of their hosts for lengthy, discovering a lot of the genetic materials from the virus intermingled with genetic materials from raccoon canine is extremely suggestive that they may have been carriers, in accordance with scientists who labored on the evaluation. The evaluation was led by Kristian Andersen, an immunologist and microbiologist at Scripps Research; Edward Holmes, a virologist on the University of Sydney; Michael Worobey, an evolutionary biologist on the University of Arizona. These three scientists, who’ve been digging into the origins of the pandemic, had been interviewed by reporters for The Atlantic journal. CNN has reached out to Andersen, Holmes and Worobey for remark.
The particulars of the worldwide evaluation had been first reported Thursday by The Atlantic.
The new knowledge is rising as Republicans in Congress have opened investigations into the pandemic’s origin. Previous research offered proof that the virus probably emerged naturally in market, however couldn’t level to a selected origin. Some US companies, together with a current US Department of Energy evaluation, say the pandemic probably resulted from a lab leak in Wuhan.
In the information briefing on Friday, WHO Director-General Tedros Adhanom Ghebreyesus mentioned the group was first made conscious of the sequences on Sunday.
“As soon as we became aware of this data, we contacted the Chinese CDC and urged them to share it with WHO and the international scientific community so it can be analyzed,” Tedros mentioned.
WHO additionally convened its Scientific Advisory Group for the Origins of the Novel Pathogens, generally known as SAGO, which has been investigating the roots of the pandemic, to debate the information on Tuesday. The group heard from Chinese scientists who had initially studied the sequences, in addition to the group of worldwide scientists taking a contemporary have a look at them.
WHO consultants mentioned within the Friday briefing that the information usually are not conclusive. They nonetheless can’t say whether or not the virus leaked from a lab, or if it spilled over naturally from animals to people.
“These data do not provide a definitive answer to the question of how the pandemic began, but every piece of data is important in moving us closer to that answer,” Tedros mentioned.
What the sequences do show, WHO officers mentioned, is that China has extra knowledge that may relate to the origins of the pandemic that it has not but shared with the remainder of the world.
“This data could have, and should have, been shared three years ago,” Tedros mentioned. “We proceed to name on China to be clear in sharing knowledge and to conduct the required investigations and share outcomes.
“Understanding how the pandemic began remains a moral and scientific imperative.”
CNN has reached out to the Chinese scientists who first analyzed and shared the information, however has not obtained a reply.
The Chinese researchers, who’re affiliated with that nation’s Center for Disease Control and Prevention, had shared their very own evaluation of the samples in 2022. In that preprint research posted final yr, they concluded that “no animal host of SARS-CoV2 can be deduced.”
The analysis checked out 923 environmental samples taken from throughout the seafood market and 457 samples taken from animals, and located 63 environmental samples that had been optimistic for the virus that causes Covid-19. Most had been taken from the western finish of the market. None of the animal samples, which had been taken from refrigerated and frozen merchandise on the market, and from stay, stray animals roaming the market, had been optimistic, the Chinese authors wrote in 2022.
When they appeared on the totally different species of DNA represented within the environmental samples, the Chinese authors solely noticed a hyperlink to people, however not different animals.
When a world group of researchers just lately took at contemporary have a look at the genetic materials within the samples – which had been swabbed in and across the stalls of the market – utilizing a sophisticated genetic approach known as metagenomics, scientists mentioned they had been stunned to discover a important quantity of DNA belonging to raccoon canine, a small animal associated to foxes. Raccoon canine might be contaminated with the virus that causes Covid-19 and have been excessive on the record of suspected animal hosts for the virus.
“What they found is molecular evidence that animals were sold at that market. That was suspected, but they found molecular evidence of that. And also that some of the animals that were there were susceptible to SARS-CoV2 infection, and some of those animals include raccoon dogs,” mentioned Maria Van Kerkhove, WHO’s technical lead for Covid-19, in Friday’s briefing.
“This doesn’t change our approach to studying the origins of Covid-19. It just tells us that more data exists, and that data needs to be shared in full,” she mentioned.
Van Kerkhove mentioned that till the worldwide scientific neighborhood is ready to overview extra proof, “all hypotheses remain on the table.”
Some consultants discovered the brand new proof persuasive, if not fully convincing, of an origin out there.
“The data does point even further to a market origin,” Andersen, the Scripps Research evolutionary biologist who attended the WHO assembly and is likely one of the scientists analyzing the brand new knowledge, advised the journal Science.
The assertions remodeled the brand new knowledge shortly sparked debate within the scientific neighborhood.
Francois Balloux, director of the Genetics Institute at University College London, mentioned the truth that the brand new evaluation had not but been publicly posted for scientists to scrutinize, however had come to mild in information reviews, warranted warning.
“Such articles really don’t help as they only polarise the debate further,” Balloux posted in a thread on Twitter. “Those convinced by a zoonotic origin will read it as final proof for their conviction, and those convinced it was a lab leak will interpret the weakness of the evidence as attempts of a cover-up.”
Other consultants, who weren’t concerned within the evaluation, mentioned the information may very well be key to displaying the virus had a pure origin.
Felicia Goodrum is an immunobiologist on the University of Arizona, who just lately revealed a overview of all obtainable knowledge for the assorted theories behind the pandemic’s origin.
Goodrum says the strongest proof for a pure spillover can be to isolate the virus that causes Covid-19 from an animal that was current out there in 2019.
“Clearly, that is impossible, as we cannot go back in time any more than we have through sequencing, and no animals were present at the time sequences could be collected. To me, this is the next best thing,” Goodrum mentioned in an e-mail to CNN.
In the WHO briefing, Van Kerkhove mentioned that the Chinese CDC researchers had uploaded the sequences to GISAID as they had been updating their authentic analysis. She mentioned their first paper is within the strategy of being up to date and resubmitted for publication.
“We have been told by GISAID that the data from China’s CDC is being updated and expanded,” she mentioned.
Van Kerkhove mentioned on Friday that what WHO would really like to have the ability to do is to seek out the supply of the place the animals got here from. Were they wild? Were they farmed?
She mentioned in the midst of its investigation into the pandemic’s origins, WHO had repeatedly requested China for research to hint the animals again to their supply farms. She mentioned WHO had additionally requested for blood assessments on individuals who labored out there, in addition to assessments on animals which will have come from the farms.
“Share the data,” Dr. Mike Ryan, government director of WHO’s well being emergencies program, mentioned Friday, addressing scientists world wide who may need related data. “Let science do the work, and we will get the answers.”