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 identified to be optimistic for SARS-CoV-2, the coronavirus that causes Covid-19. A big quantity of that DNA seems to belong to animals often known as raccoon canines, which have been identified to be traded on the market, in keeping with officers with the World Well being Group, who addressed the brand new proof in a information briefing on Friday.
The connection to raccoon canines got here to mild after Chinese language researchers shared uncooked genetic sequences taken from swabbed specimens collected on the market early within the pandemic. The sequences have been uploaded in late January 2023, to the info sharing web site GISAID, however have lately been eliminated.
A world workforce of researchers observed them and downloaded them for additional research, the WHO officers mentioned Friday.
The brand 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 canines have been contaminated with SARS-CoV-2, nor do they show that raccoon canines have been the animals that first contaminated individuals.
However as a result of viruses don’t survive within the atmosphere outdoors of their hosts for lengthy, discovering a lot of the genetic materials from the virus intermingled with genetic materials from raccoon canines is very suggestive that they may have been carriers, in keeping with scientists who labored on the evaluation. The evaluation was led by Kristian Andersen, an immunologist and microbiologist at Scripps Analysis; Edward Holmes, a virologist on the College of Sydney; Michael Worobey, an evolutionary biologist on the College of Arizona. These three scientists, who’ve been digging into the origins of the pandemic, have been interviewed by reporters for The Atlantic journal. CNN has reached out to Andersen, Holmes and Worobey for remark.
The small print of the worldwide evaluation have been first reported Thursday by The Atlantic.
The brand new knowledge is rising as Republicans in Congress have opened investigations into the pandemic’s origin. Earlier research offered proof that the virus doubtless emerged naturally in market, however couldn’t level to a selected origin. Some US businesses, together with a current US Division of Vitality evaluation, say the pandemic doubtless resulted from a lab leak in Wuhan.
Within the information briefing on Friday, WHO Director-Basic 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, often known as SAGO, which has been investigating the roots of the pandemic, to debate the info on Tuesday. The group heard from Chinese language scientists who had initially studied the sequences, in addition to the group of worldwide scientists taking a recent have a look at them.
WHO consultants mentioned within the Friday briefing that the info 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 which 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 mandatory investigations and share outcomes.
“Understanding how the pandemic began remains a moral and scientific imperative.”
CNN has reached out to the Chinese language scientists who first analyzed and shared the info, however has not obtained a reply.
The Chinese language researchers, who’re affiliated with that nation’s Heart for Illness Management 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 have been optimistic for the virus that causes Covid-19. Most have been taken from the western finish of the market. Not one of the animal samples, which have been taken from refrigerated and frozen merchandise on the market, and from stay, stray animals roaming the market, have been optimistic, the Chinese language authors wrote in 2022.
Once they appeared on the totally different species of DNA represented within the environmental samples, the Chinese language authors solely noticed a hyperlink to people, however not different animals.
When a world workforce of researchers lately took at recent have a look at the genetic materials within the samples – which have been swabbed in and across the stalls of the market – utilizing a complicated genetic approach known as metagenomics, scientists mentioned they have been shocked to discover a vital quantity of DNA belonging to raccoon canines, a small animal associated to foxes. Raccoon canines might be contaminated with the virus that causes Covid-19 and have been excessive on the listing 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 assessment 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 Analysis evolutionary biologist who attended the WHO assembly and is likely one of the scientists analyzing the brand new knowledge, instructed the journal Science.
The assertions remodeled the brand new knowledge rapidly sparked debate within the scientific neighborhood.
Francois Balloux, director of the Genetics Institute at College School 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 studies, 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.”
Different consultants, who weren’t concerned within the evaluation, mentioned the info could possibly be key to exhibiting the virus had a pure origin.
Felicia Goodrum is an immunobiologist on the College of Arizona, who lately printed a assessment of all obtainable knowledge for the assorted theories behind the pandemic’s origin.
Goodrum says the strongest proof for a pure spillover could 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.
Within the WHO briefing, Van Kerkhove mentioned that the Chinese language CDC researchers had uploaded the sequences to GISAID as they have been updating their unique analysis. She mentioned their first paper is within the technique 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 love to have the ability to do is to search out the supply of the place the animals got here from. Have been they wild? Have been they farmed?
She mentioned in the middle 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 checks on individuals who labored out there, in addition to checks on animals which will have come from the farms.
“Share the data,” Dr. Mike Ryan, govt director of WHO’s well being emergencies program, mentioned Friday, addressing scientists all over the world who might need related data. “Let science do the work, and we will get the answers.”