“There is no indication of [COVID-19] in the population before December 2019,” he said.
Dr Liang said it was not possible on the basis of the epidemiological work to determine how COVID-19 was introduced to the Wuhan market.
“While some of the early cases had an association with the market, others were associated with other markets and others had no association with markets at all,” he said.
Speaking from the Hilton Optics Valley Hotel in Wuhan, WHO team leader Peter Ben Embarek, a scientist for food safety and zoonosis, said a laboratory incident hypothesis was extremely unlikely to explain the introduction of the virus. The Trump administration had previously targeted the Wuhan Institute of Virology as a potential first exposure site for the virus.
“Therefore it is not a hypothesis we suggest to support for our future work,” he said.
He said that the most likely hypothesis was a transmission to humans via an intermediate animal. He added that the virus could have been spread through frozen animal product.
“The market was dealing primarily with frozen animal product but there were also vendors selling products from domesticated wildlife and imported products,” he said.
“There is the potential to continue to follow this lead and animals that were supplied to the market in frozen and other semi processed or raw form. We have to do much more work on the cold-food product chain.”
Dr Embarek said it was possible “the virus was also present in other places and individuals in other countries” and urged further investigation.
“Did we change the picture dramatically compared to what we had before? I don’t think so,” he said. “Did we improve our understanding and add details? Absolutely.”
The group of 14 scientists arrived in China on January 14 but had to undergo a fortnight of quarantine before being allowed into the field. In a whirlwind two-week period, the team of virologists, epidemiologists, veterinarian and food safety specialists visited key sites that have been related to the outbreak of the disease which has killed 2.3 million people.
The investigation included the Huanan Seafood Market, where the first cases of COVID-19 were reported, the Wuhan Institute of Virology, the Hubei Province Centre for Disease Control and the Prevention and the Hubei Provincial Hospital, where patients sick with a mystery disease first overwhelmed hospital workers in December 2019.
The visits have been closely guarded, with limited details being released ahead of Tuesday’s press conference. In the lead up to the initial report, Dr Embarek was careful to manage expectations of the investigation delivering concrete findings within a short timeframe.
“I don’t think we will have clear answers after this initial mission, but we will be on the way,” he said.
Australian WHO investigator Dominic Dwyer, a microbiologist at Westmead Hospital, said in January the inquiry was about trying to shine a light on how the outbreak began.
“The outbreak certainly started in China, whether the virus started in China is difficult to tell,” he said.
Chinese authorities initially suppressed any reporting of the disease in December, punishing doctors including whistleblower Li Wenliang for spreading rumours, before reversing and locking down Wuhan and 57 million people across Hubei province by January 23 in what was then seen as an unprecedented public health response. The lockdown did not prevent the virus from travelling across Asia, Europe, Africa, Australia and South and North America within months, hammering the global economy into recession as borders went up.
China allowed the WHO investigators into Wuhan after global diplomatic pressure led to a unanimous vote in May at the World Health Assembly for an “impartial, independent and comprehensive” inquiry into the origins of the coronavirus.
The WHO vote followed weeks of negotiations led by Australia and the European Union and put the Morrison government at the centre of a diplomatic furore that has since seen Beijing launch more than $20 billion in trade strikes on half-a-dozen industries.
China has accused Australia of running a politically motivated campaign by “hyping up” the probe and has called for inspectors to also travel to the United States and Europe.
China’s Foreign Ministry spokesman Wang Wenbin on Monday night reiterated their government’s claim that the virus may have started elsewhere.
“More and more facts have shown that the virus and epidemics had been present in multiple places as early as in the second half of 2019,” he said.
“Tracing the origin of the virus is a complex scientific issue, which does not fall within the scope of diplomacy and should not entail any political factors.”
Michael Ryan, WHO’s director of the health emergencies program, said in November it would be “highly speculative” to argue the disease did not first emerge in China.
“It is clear from a public health perspective that you start your investigations where the human cases first emerged,” he said.
What in the World
Eryk Bagshaw is the China correspondent for The Sydney Morning Herald and The Age. Due to travel restrictions, he is currently based in Canberra.