Thread by @latikambourke

[thread]

WHO joint expert team investigating the origins of coronavirus is holding a news conference in Wuhan.

WHO and Chinese govt established a joint team to investigate origins of COVID-19 and it's route to humans.

(English is all being said through a translator).

WHO: The global origin tracing work will therefore not be bound to any geographic location.

So far quotes attributable to Liang Wannian (head of the Head of Expert Panel of COVID-19 Response of
China National Health Commission (NHC).

Finally to key findings.

Liang: As most emerging virus originate from animals requires deep analysis of evolution of viruses in animal reservoir.

Generally speaking a virus causing pandemic must be highly adaptive to human environment, each step driven by natural selection.

Liang: The search for the origins needs to focus on two phases:

* Search for reservoir (animal) host.
* Covid-19 may have emerged from zoonotic transmission but the reservoir host is yet to be identified.

Liang: The second phase involving the evolution of Covid-19 - the likelihood of spillovers, may happen frequently resulting in mutations in different geographical locations.

Liang: Covid-19 most likely to be found in bats and pangolins suggesting these animals as hosts - but viruses identified from these two so far are not sufficiently similar.

Liang: the feline family could be a potential reservoir given the susceptibility of mink and cats to Covid-19.

Liang: Possibility of missed earlier circulation of Covid-19 in other locations. Suggesting a determination of review after global data.

So far the gist of this is - we know nothing for certain but we've officially moved the WHO into accepting the idea repeatedly put forward by China that it may not be the epicentre of COVID-19.

Liang: No substantial unrecognised circulation of Covid-19 in Wuhan during latter half of 2019.

Liang: Analysis of retail pharmacy products have also been conducted and it did not provide a useful indicator of early Covid-19 (being present in Wuhan).

Liang: July to December 2019 - reviewed all-cause mortality from Wuhan and Hubei, 'little evidence' in fluctuations of mortality that might suggest transmission of Covid-19.

Liang: there is no indication of transmission of Covid-19 in Wuhan before December 2019.

This is only going to embolden those accusing @WHO under @DrTedros of being whitewashed by China.

Liang: tests of blood banks showed negative antibodies for Covid-19.

Liang: It is considered unlikely that substantial transmission of Covid-19 was occurring in Wuhan in those two months.

Liang says at the time of spread of Covid-19 at Huanan market the virus was also spreading in Wuhan elsewhere

It it is not possible to determine how Covid-19 was transmitted into the market.

Liang: Some cases elsewhere had links to the market, other markets as well as no markets at all.

It is not possible to determine how Covid-19 was introduced into the Huanan market, he repeats.

Liang: Coronaviruses that genetically relate to Covid-19 have been found in horseshoe bats and pangolins but they haven't found it in bats in the wild in China so far.

Liang: Covid-19 can be found in frozen food and packaging. It has been found in the cold chain, indicating that it can be carried long-distance on cold-chain products.

Liang: further research will be carried out into transmission via cold-chain products, (includes frozen and refrigeration temps).

In Huanan market, sig. number sell cold-chain products but data not available to prove links. Research needed.

Now we are over to Peter Ben Embarek - WHO’s top expert on zoonotic diseases.

Ben Emebarek: We came here with two goals - one to find out what happened at the beginning of the pandemic.

We've focussed on trying to understand what happened during that period.

Ben Embarek: In parallel we also embarked on trying to understand how it happened, how did the virus emerge, how it jumped into the human population.

Ben Embarek: 'Did we change dramatically the picture we had beforehand? I don't think so.'

But Ben Embarek says crucial details have been added to the story, referring to the findings presented earlier by Liang (who basically suggested the virus could have emerged outside China).

Ben Embarek: We did not find evidence of large outbreaks that could be linked to Covid-19 prior to December in Wuhan.

We can also agree that we found wider circulation of the virus in Wuhan in Dec - not just confined to the Huanan market.

Ben Embarek: the picture we see is a very classic picture of an outbreak - few sporadic outbreaks then small outbreaks where clusters start to emerge.

Eg - the market.

Ben Embarek: these early clusters are usually the way one detects the first cases, the first sign of these emerging viruses and that's what we see in the month of December.

Some pushback there on China's theory that it was imported?

Ben Embarek: it has not been possible to pinpoint any animal as the reservoir for this virus. Doesn't look like any circulation of the virus in the animal species anywhere in China.

(Watch those who think it escaped from the lab jump on this)

Ben Embarek - says the next step is to look at the future. How will we advance the search for the start of the story.

(So far no statements on the lab theory)

Ben Embarek: 4 hypotheses on how COVID-19 jumped into the human population.

1. Direct zoonotic spillover from species or reservoir into the human population - direct jump from an animal to a human.

2. Intermediary host species, a second, potentially closer to humans.

In the second case, this would be an animal where the virus adapts easily and jumps to humans.

3. Food chain: potential for frozen products acting as the surface for the transmission of the virus into the human population or food-related routes of transmission.

Final hypothesis - 'the possibility of a lab-related incident.'

Our initial findings suggest that the intermediary is the most likely pathway and one that will require more studies and more specific, targeted....[research I think - link is breaking up].

But Ben Embarek says weight is also placed on the third hypothesis that the virus could have been transmitted via cold-chain route.

WHO rules out further investigation into Covid-19 originating from lab: 'extremely unlikely to explain the introduction of the virus into the human population and is therefore not a hypothesis that implies future studies to support our work into understanding origin of the virus'

Ben Embarek now keeping open the possibility of coronavirus being present in 'other countries' (before Wuhan).

Ben Embarek says an investigation of bat populations OUTSIDE China will be needed.

Ben Embarek says a frozen wild animal that was infected could have been the vehicle for the virus into the market where the temperature would have enabled the viruses rapid spread.

Now Ben Embarek says Covid-19's origin could have been through a very "convoluted route" involving "movement across borders" and travels before arriving in the market.

That was just the intros. No questions so far. And we're 90 mins in...

this presser requires more stamina than a Peloton ride

Ben Embarek says they don't know the 'exact role' of the Huanan market beyond that there was spread. How it was introduced is still unknown. We have a picture of where the cases were, we have genetic sequences for some of the cases.

Ben Embarek - it could be a trader, a visitor, it could be a product. Frozen wild animals susceptible to these viruses were sold there.

SKY UK asks panel to explain why they discounted only one hypothesis - the lab leak theory.

Ben Embarek: "In short, it's about yes, accidents do happen, unfortunately, we have many examples from many countries in the world of past accidents, so of course this is not impossible, it happens once in a while.'

Embarek on argument discounting Covid-19 originating from lab leak - no-where had this virus been studied. We discussed with managers of labs in the region and hearing from them how their audits and staff monitoring programs [were run].

"We looked at the Wuhan Inst. of Virology and it was very unlikely that anything could escape from such a place."

- Lab accidents extremely rare, these are extremely rare events. This would not happen on a regular basis.

Liang: The idea that Covid-19 was human engineered (and leaked from lab) was refuted by entire scientific community.

In all the labs in Wuhan, they uphold a very stringent management system.

Lab leak 'extremely unlikely.'