GENEVA – The chief of the World Health Organisation (WHO) pressed China on Thursday to share its information about the origins of Covid-19, saying that until that happened, all hypotheses remained on the table, more than three years after the virus first emerged.

“Without full access to the information that China has, you cannot say this or that,” said WHO director-general Tedros Adhanom Ghebreyesus in response to a question about the origin of the virus.

“All hypotheses are on the table. That is WHO’s position and that is why we have been asking China to be cooperative on this.”

If China does that, then “we will know what happened or how it started”, he added.

The virus was first reported in the Chinese city of Wuhan in December 2019, with many suspecting that it spread in a live animal market before fanning out around the world and killing nearly seven million people.

Data from the early days of the Covid-19 pandemic was briefly uploaded by Chinese scientists to an international database in March 2023. It included genetic sequences found in more than 1,000 environmental and animal samples taken in January 2020 at the Huanan seafood market in Wuhan, the location of the first known Covid-19 outbreak.

The data showed that DNA from multiple animal species – including raccoon dogs – was present in environmental samples that tested positive for Sars-CoV-2, the virus that causes Covid-19, suggesting that they were “the most likely conduits” of the disease, according to a team of international researchers.

However, in a non-peer-reviewed study published by the Nature journal this week, scientists from China’s Centre for Disease Control and Prevention disputed the international team’s findings.

They said the samples provided no proof that the animals were actually infected.

The samples were also taken a month after human-to-human transmission first occurred at the market, so even if they were Covid-19-positive, the animals could have caught the virus from humans.

Dr Maria Van Kerkhove, the WHO’s technical lead for Covid-19, said the latest Chinese information offered some “clues” on origins but no answers.

She said the United Nations agency was working with scientists to find out more about the earliest cases from 2019, such as the whereabouts of those infected.

She added that the WHO still did not know whether some of the research required had been undertaken in China.

The WHO has also asked the United States for original data that underpinned a recent study by the US Energy Department that suggested a laboratory leak in China had likely caused the Covid-19 pandemic, she said. REUTERS