Data from first days of the COVID-19 pandemic which were briefly uploaded to a global database by Chinese scientists, gives critical information about its origin, including an animal market in the Chinese city of Wuhan, researchers said.

The virus was first identified in Wuhan in December 2019, with many nA live animal market in Huanan is suspected as the source, before it spread around the world and killed seven million people.

The scientists released a report ahead of peer review of their own interpretation of the data on Monday, following leaks to the media last week and a meeting with the World Health Organization, which called on China to release more information. .

The data from the Chinese Center for Disease Control and Prevention (CDC) is no longer available in the GISAID database where it was located by the scientists.

They included new sequences of the SARS-CoV-2 virus and additional genomic data based on samples taken from the live animal market in Wuhan in 2020, according to scientists who had access to them.

The sequences showed that the raccoon dogs and other animals vulnerable to the coronavirus were on the market and may have been contaminated, providing a new link in the chain of transmission that eventually reached humans, they said.

“This adds to the body of evidence identifying the Huanan market as the jumping off point for Sars-CoV-2 and the epicenter of the COVID-19 pandemic,” according to the report.

The report is signed by authors including Michael Worobey of the University of Arizona, Christian Andersen of Scripps Research in La Jolla, California, and Florence Debard of the Sorbonne University in Paris, who had access to the data.

Compared to the information leaked last week, the report adds more details about other animals that were present in the market and it also shows that some of the SARS-CoV-2 positive environmental samples had more animal than human genetic material in them, which the scientists say is consistent with animal contamination.

World Health Organization officials said last week that the information is not definitive but does represent a new element in the investigation into the origins of COVID and should be shared immediately.

The UN agency has previously said all hypotheses about the origin of COVID-19 remain on the table, including one that the virus escaped from a high-security laboratory in Wuhan that studies dangerous pathogens.

China denies any such link. WHO has also said that most evidence points to that the virus came from animals, possibly bats.

The Chinese CDC was not immediately available for comment. On Monday, when asked by Reuters why the data first appeared online and then disappeared, and whether the information would eventually be shared, Chinese Foreign Ministry spokesman Wang Wenbin referred reporters to the “competent authorities” without elaborating.

The Chinese Foreign Ministry spokesman said China had “always supported and participated in global scientific cooperation to identify the source” and would continue to do so, but said the international scientific community should also share “its research on the origin of virus from other parts of the world including China”.