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Saturday, May 08, 2021

World Health Organization (WHO) report on the natural origin theory of SARS-CoV-2

The origin of SARS-Cov-2 is a hot topic these days. As far as I can tell, the consensus view among the experts is that the ancestor is from bats but it evolved in an intermediate host before jumping to humans. However, there's a vocal group who claim that the virus was engineered in a lab in the Wuhan Institute of Virology and accidentally escaped causing a pandemic. A group of scientists from WHO investigated this speculation and decided that it was "extremely unlikely." I posted a summary of their analysis a few days ago [World Health Organization (WHO) report on the lab leak conspiracy theory].

That's not going to put an end to the speculation since proponents of the lab leak hypothesis are now saying that the WHO report, and the opinion of other experts, can't be trusted. They claim that there's a widespread consiracy to lie and cover up the fact that SARS-CoV-2 was created in a lab and leaked to the Wuhan population.

There's not much point in arguing with people once they go down the conspiricy theory path since they will refute every argument by claiming that it's part of the conspriacy. However, it's worth pointing out that there's a perfectly valid alternative explanation; namely, natural origin. For those who still have an open mind I'm posting the explanation of the WHO scientific team who conclude that this is the most likely explanation [WHO-convened global study of origins of SARS-CoV-2: China Part].

Introduction through intermediate host followed by zoonotic transmission

Explanation of hypothesis

SARS-CoV-2 is transmitted from an animal reservoir to an animal host, followed by subsequent spread within that intermediate host (spillover host), and then transmission to humans. The passage through an intermediate host can be without or with virus adaptation.

Arguments in favour

Although the closest related viruses have been found in bats, the evolutionary distance between these bat viruses and SARS-CoV-2 is estimated to be several decades, suggesting a missing link (either a missing progenitor virus, or evolution of a progenitor virus in an intermediate host). Highly similar viruses have also been found in pangolins, suggesting cross-species transmission from bats at least once, but again with considerable genetic distance. Both these putative hosts are infrequently in contact with humans, and an intermediary step involving an amplifying host has been observed for several other emerging viruses (Henipaviruses, influenza viruses, SARS-CoV and MERS-CoV). SARS-CoV-2 infection and intraspecies spread (including further transmission to humans) has been documented in an increasing number of animal species, particularly mustelids and felids. SARS-CoV-2 adapts relatively rapidly in susceptible animals (such as mink). The increasing number of animals shown to be susceptible to SARS-CoV-2 includes animals that are farmed in sufficient densities to allow potential for enzootic circulation. High-density farming is common in many places across the world and includes many livestock species as well as farmed wildlife. There was a large network of domesticated wild animal farms, supplying farmed wildlife. In high-density farms, there often are connections between farms (for instance, through the workforce and food supply), leading to complex transmission pathways that may be difficult to unravel, as was observed in other zoonotic outbreaks involving farmed animals. Optimized conditions for sustained virus transmission chains in large-scale animal farms may also impact on virus seasonality in favour of a year-round endemic transmission pattern, and thereby increasing the zoonotic risk in winter months.

Arguments against

SARS-CoV-2 has been identified in an increasing number of animal species, but genetic and epidemiological studies have suggested that these were infections introduced from humans, rather than enzootic virus circulation. In addition, since the containment of SARS-CoV-2 in China, new outbreaks have occurred for which genomic sequence data was generated. Based on epidemiological analysis and genetic sequencing of viruses from new cases throughout 2020, there is no evidence of repeated introduction of early SARS-CoV-2 strains of potential animal origins into humans in China. There was no genetic or serological evidence for SARS-CoV-2 in a wide range of domestic and wild animals tested to date. The screening of the major livestock species was done across the country and provided no evidence for circulation of a related virus. The scale of testing in these species was such that widespread circulation is extremely unlikely. Screening of farmed wildlife was limited but did not provide conclusive evidence for the existence of circulation.

Assessment of likelihood

Based on the above arguments, the scenario including introduction through an intermediary host was considered to be likely to very likely.

I should note that it's often very difficult to figure out who's right and who's wrong in a scientific controversy but in general there's one group that appears to be thinking critically and one that's not. Critical thinking is also hard to recognize but when I was teaching it we emphasized one important clue. Critical thinkers usually present both sides of an argument and discuss not only their own opinions but also the views of the other side. That's one of the things that impress me about the WHO report. It doesn't mean that they are necessarily correct but they sure look a lot better than proponents of the lab leak conspiracy theory who seem to dismiss out of hand the possibility of a natural origin.

I'd also like to make note of the fact the WHO is not a perfect organization. They have made mistakes during this pandemic as have every single government on the planet (some more than others). I'm not defending everything that WHO has done but I don't see any reason to be overly suspicious of the integrity of the scientists who wrote this report.


Nesslig20 said...

I have talked about this "theory" too on the League of Reason forum.

. said...

"That's not going to put an end to the speculation since proponents of the lab leak hypothesis are now saying that the WHO report, and the opinion of other experts, can't be trusted. They claim that there's a widespread consiracy to lie and cover up the fact that SARS-CoV-2 was created in a lab and leaked to the Wuhan population."

You have two statements in here that don't go hand in hand. One can make an argument that the WHO report is unreliable without invoking a widespread conspiracy that there a huge coverup. An unreliable WHO investigation is not mutually exclusive with a natural origin.

Why do you continue to evade the sociopolitical situation that surrounded the investigation? There are a number of reasons why it wasn't a reliable source of information:

1. The WHO team were not given direct access to the data and had to rely upon the information given to them by the Chinese authorities. The team is on record as saying that they did not have the independence, authority, and in some cases, the expertise to carry out a full investigation into the possibility of a lab leak. They are on record as saying that the Chinese team was most qualified to determine if there was a lab leak despite the lab having a clear conflict of interest. Moreover, everything included in the WHO report required approval from the Chinese authorities.

This would limit a possible coverup to the Wuhan Institute Scientists and Chinese authorities who knew about the leak. This wouldn't necessarily involve all of the scientists working at the WIV. If there was a coverup, there is no reason to believe that this involved the WHO team outside of the institute.

2. The Chinese authorities have a proven track record of trying to coverup the pandemic. In the early stages they detained and censored scientists and doctors, they destroyed samples, and lied about transmissibility between humans. This wasn't limited to the early stages either, as they have continued to show an unwillingness to be transparent. After the initial coverup, they delayed the WHO investigation for over a full year, and implemented a vast tech surveillance and censorship apparatus monitoring discussions of the pandemic. For the WHO report to be trustworthy, you would need to prove that the Chinese authorities are being transparent about the investigation despite of all of these actions.

3. If there was a coverup, it would be unreasonable to expect the Wuhan Institute's scientists to be truthful. The Chinese authorities have already shown that they will persecute scientists that speak out of line. They continue exert control over the dissemination of information surrounding the pandemic. Would you expect the scientists to be truthful if they faced persecution for doing so? I wouldn't, and I am not questioning their integrity. I believe that most people would lie if it prevented harm to themselves and their families. This has already been shown for information obtained from torture or highly aggressive police interrogations. Had they been interviewed anonymously in a different country and were offered safe haven, I would take a different position.

If we really want to lay this to rest, we should call for a thorough investigation that is both thorough and independent.

Disclaimer: I have always been careful with my language, but it bears repeating that I do equate criticisms of the Chinese government with those of the Chinese people. By arguing that the Wuhan Institute scientist's testimonies should not be considered to be reliable, I am only arguing that they are not in a position to be truthful. This is in no way meant to be an attack on their character or integrity.

Unknown said...

Thank you for your excellent commnetary.

Woody Benson said...

If you want a cover-up, what about the US government in the person of "Supreme Leader" Donald Trump who was informed personally by Xi Jinping in early Feb., 2020, that the new virus has airborne transmission and was several times more lethal than the flu. The Chinese government placed no restrictions on Trump, but the latter kept this info secret from the public so as not to "spread panic". Xi's info was never released by Trump or the US government nor were they followed up with inquiries concerning dangers presented by the virus. We learned about Xi's warning on the danger of pandemic 7 months later, in September, when Bernstein's book came out.
Skeletor seems to confound local "Chinese authorities" around Wuhan with those of the central government and neglects to put a time frame on the Chinese response. The first cases of virus were reported in late November, 2019. Initially they were confused with an ongoing outbreak of the common flu. In December doctors began noting that there was a new disease and tried to put out an alert. Local authorities, focused on New Year's celebrations, and (I assume) because of the relatively small number of cases at the time, underestimated the danger and suppressed the alert. By the end of December it was becoming general knowledge that a new dangerous virus was circulating. The time delay (say Dec.10-Jan.10) was on the order of 3-5 weeks, and still hard data, the type required by WHO, were lacking.
It should be noted, different from the US and Europe, the Chinese had no advanced warning and were taken completely by surprise by the new disease. I first learned about the outbreak in late January (2020) from reports that Yuhan was on lockdown. Some doctor friends I contacted ventured it was no more than some type of flu that would go away by spring. Sound familiar? Researchers in Shanghai sequenced the virus and posted their results on-line before mid-January (according to them, with no government interference). The Yuhan lockdown abt. Jan. 23, 2020 spoke for itself. At that point, 2+2 = 4. Even then it took a few more days for WHO to get on board.
If I were to place blame, heavy blame, on anyone, it would be the West's incompetent intelligence gathering and interpretation and a sleepy medical warning system that couldn't predict that the world was facing an avoidable disaster.
Nothing makes me think the virus came from a lab. Much of south China is limestone bat-cave country, and many wild mammals den associated with bats. A wide variety of creatures that could serve as hosts are also captured and raised by local people for sale and consumption. If I am not mistaken (and I may be because I did not take notes), some very early COVID-2 cases were from places other than Yuhan (and associated with neither the fresh-meat market nor the virus institute). In the absence of molecular evidence (which I am not competent to evaluate), the simple fact that a virus research facility was near the early outbreak is not compelling. I would suspect that if the Chinese were militarizing viruses, they would work from high-security, top-secret labs in some isolated region, the geographical equivalent of Colorado.
Also, were the virus to have originated in the Yuhan lab, it is hard to imagine that, given that early symptoms, when they exist, are similar to those of H1N1, the escaped virus would have been detected before spreading to WVI staff. This obviously didn't happen.
In my view it is vanishing unlikely that SARS-CoV-2 was created, intentionally or not, by human hands.

Georgi Marinov said...

"I'd also like to make note of the fact the WHO is not a perfect organization. They have made mistakes during this pandemic as have every single government on the planet (some more than others). I'm not defending everything that WHO has done but I don't see any reason to be overly suspicious of the integrity of the scientists who wrote this report."

There are "mistakes" and then there are obvious deliberate lies.

Hospitals in Wuhan overflowing with sick patients and you claiming "no evidence for human-to-human spread" is not a "mistake", it is an obvious deliberate lie.

Wuhan under draconian lockdown and crematoriums not being able to keep up and you telling governments "don't close borders" (and guess who did well -- the countries that did not listen to that "advice") is not a "mistake", it is another obvious deliberate lie. It is also quite obvious why it was told.

Insisting "it is not airborne" for more than a year, even after it has been pointed out countless times to you that it is, with mountains of irrefutable evidence, is not a "mistake", it is an obvious deliberate lie. And again, we all know why it was told.

This sort of thing from the last few days:

Is also not a "mistake", it is obviously 100% deliberate, and it is also obvious why it is done.

Scientific integrity mandates that you do not bow down to political pressure.

It also mandates that when someone is telling obvious lies under political pressure you point out that those are lies instead of making excuses.

dean said...

And here we see how tightly conspiracy mongers are to their personal favorite conspiracies. Rather like the modern Republican leadership, facts mean nothing to them.