A team member from the World Health Organisation-led mission investigating the origins of Covid-19 has downplayed the likelihood the virus was transported from the West by frozen products ahead of a highly-anticipated report on their findings.
The cold-chain transmission theory, where it is believed the virus can be transported large distances on frozen items, is one of four potential sources experts are entertaining and has been one that has been repeatedly pushed by China.
Lead Chinese scientist Liang Wannian said last week the cold chain transmission "plays an important part" in the virus's origins. It follows a persistent campaign from state-run Chinese media, both local and international, that looks to deflect blame for the pandemic.
However, team member Vladimir Dedkov who was part of the Wuhan visit at the start of the year told the Associated Press the theory was far down on the list of likely sources.
He suggested frozen products on which the virus was found were most likely contaminated by infected people.
An infected person also likely brought and spread the virus at the Wuhan market associated with the outbreak, where some of the contaminated products were later found.
“In general, all the conditions for the spread of infection were present at this market,” Mr Dedkov said.
“Therefore, most likely, there was a mass infection of people who were connected by location.”
Wuhan lab leak cannot be dismissed, says Aussie expert
Mr Dedkov also said it was highly unlikely the virus leaked from a lab, echoing previous comments from lead scientist Peter Ben Embarek.
However, Professor Nikolai Petrovsky, an expert in vaccines at Flinders University, told Yahoo News Australia such a theory was being dismissed too early.
"The only mandate of this panel is to explore the natural animal transmission hypothesis," he said.
He questioned whether the Western team of experts were granted the relevant studies and data on a potential lab leak from the Wuhan Institute of Virology, meaning they would "not be considered competent to comment on this possibility".
When questioned by Yahoo News Australia on how the team had concluded the theory was highly unlikely, a WHO spokesperson declined to comment.
Yet Mr Dedkov noted if some data had not been collected, it wasn't because the Chinese side had tried to conceal something.
He and Professor Petrovsky both noted the mission was more analysis than an investigation.
“We did not collect any samples ourselves, we didn’t carry out any laboratory studies there, we just analysed what we were being shown,” Dedkov said.
Liang said data of the original cases in Wuhan could not be taken away by the WHO team due to privacy restrictions of the individuals.
Honorary Professor Colin D Butler at ANU's National Centre for Epidemiology and Population Health, told Yahoo News Australia the claim was "implausible".
The leading theory of the team remains that Covid-19 was passed to humans through an intermediary animal from a bat.
WHO report likely to be deemed 'insufficient'
The report is expected to be released this week after a delay earlier this month.
The lengthy report is being published after months of wrangling, notably between US and Chinese governments, over how the outbreak emerged, while scientists try to keep their focus on a so-far fruitless search for the origin of a microbe that has killed over 2.7 million people and stifled economies worldwide.
Critics have raised questions about the objectivity of the team, insisting that China’s government had a pivotal say over its composition. Defenders of the World Health Organization, which assembled the team, say it can’t simply parachute in experts to tell a country what to do — let alone one as powerful as China.
“I expect that this report will only be a first step into investigating the origins of the virus and that the WHO secretariat will probably say this,” said Matthew Kavanagh, director of Georgetown University’s Global Health Policy and Governance Initiative at the O’Neill Institute.
“And I expect some to criticise this as insufficient. I think it is key to keep in mind that WHO has very limited powers.”
The Wuhan trip is billed as Phase 1 in a vast undertaking to flesh out the origins of the virus.
Delays in deploying the international team to China, repeated slippage in the timing of publication of the report, and rejigging of the plans for it — an initial summary of findings was jettisoned as an idea — have only fanned speculation that the scientists have been steered by political authorities or others.
US charge d’affaires in Geneva Mark Cassayre said on Wednesday he has a "clear understanding that other studies will be required".
He said the US was hopeful the report would be a “real step forward for the world understanding the origins of the virus, so that we can better prepare for future pandemics. That’s really what this is about.”
The WHO leadership, including Director-General Tedros Adhanom Ghebreyesus, repeatedly praised the Chinese government’s early response to the outbreak, though recordings of private meetings obtained by The Associated Press exposed how top WHO officials were frustrated at China’s lack of cooperation.
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