A World Health Organization (WHO) advisory group has called on China to publish all information on the origin of the "COVID-19 pandemic" after Beijing published information on an international database and then withheld it shortly after.
Earlier this year, Chinese scientists published new sequences of SARS-CoV-2 (the coronavirus that causes COVID-19) as well as additional genetic data based on samples taken from a live animal market in Wuhan, China, in 2020, the group said in a statement published on Saturday.
The data was briefly published on the Global Initiative for Sharing Avian Influenza Data (GISAID) database, which allowed researchers in other countries to see it.
The sequences showed that raccoon dogs were on the market and may also have been infected with the coronavirus, providing new evidence in the chain of transmission that eventually reached humans.
The Chinese Center for Disease Control and Prevention later restricted access to that information "to allow for further updating of the data," according to the advisory group's statement.
WHO officials discussed the matter with Chinese colleagues who said the new data would have been used to update an initial version of a 2022 study. The Chinese center plans to send the study to the journal Nature, according to the statement.
Global health officials say this information, while not conclusive, represents a new thread in the investigation into Covid origins and must be shared immediately.
WHO Director-General Tedros Adhanom Ghebreyesus said on Friday: "These data do not provide a definitive answer to the question of how the pandemic began, but every piece of data is important to bring us closer to that answer."
"This data could and should have been shared three years ago." He added that his organization continues to call on China "to be transparent in sharing data, conducting necessary investigations and sharing results."
WHO has mandated the Advisory Group to continue investigating the origins of the pandemic, which has killed nearly 7 million people around the world.
Chinese reply
George Zhao, a professor at the Institute of Microbiology at the Chinese Center for Disease Control and Prevention, said in response to a question from Reuters why the sequences had not been published previously, that the data was "newly analysed and nothing new".
The Chinese scientist added that it was the "Global Initiative to Share Avian Influenza Data" that deleted the sequences, not the scientists.
"All of this should be left to scientists to work on, not journalists or the public. We're eager to know the answer."
Chinese authorities closed the Huanan seafood wholesale market in Wuhan after the emergence of the new coronavirus in the city in late 2019. Since then, the market has been the focus of a study to see if the virus infected several other species before it was transmitted to humans.
The World Health Organization and other scientists said they could not rule out the possibility that the virus emerged from a high-security laboratory in Wuhan studying dangerous pathogens. China denies any such hypothesis.
A preliminary 2022 paper said a small percentage of 923 samples collected from stalls and sewage systems in the market and surrounding area tested positive for the virus, and no virus was detected in 457 animal samples tested.
This paper initially stated that raccoons were not among the animals tested.
The WHO Advisory Group's statement said the new analysis suggests that "raccoons and other animals may have existed before the market was cleaned."