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In the article “The Evidence which Suggests that This Is No Naturally Evolved Virus” by Sørensen, Dalgleish and Susrud, uploaded by Minerva today, Sørensen and his co-authors present several arguments for why they consider a non-natural origin for the novel coronavirus to be the most logical explanation on how the virus evolved.
It is observations on the spike protein of the Sars-Cov-2 virus that leads Sørensen and his co-authors to believe that the virus has originated in a laboratory.
“There are several factors that point towards this”, Sørensen told Minerva in an interview last week. “Firstly, this part of the virus is very stable; it mutates very little. That points to this virus as a fully developed, almost perfected virus for infecting humans.
“Secondly, this indicates that the structure of the virus cannot have evolved naturally. When we compare the novel coronavirus with the one that caused SARS, we see that there are altogether six inserts in this virus that stand out compared to other known SARS viruses”, he goes on explaining.
Sørensen says that several of these changes in the virus are unique, and that they do not exist in other known SARS coronaviruses.
“Four of these six changes have the property that they are suited to infect humans. This kind of aggregation of a type of property can be done simply in a laboratory, and helps to substantiate such an origin”, Sørensen argues.
Sørensen was also quoted saying that he is quite confident that the virus originated in a laboratory. “I think it’s more than 90 percent certain. It’s at least a far more probable explanation than it having developed this way in nature”, Sørensen said.
Sørensen also highlights other data than those related to the virus’ properties:
“The properties that we now see in the virus, we have yet to discover anywhere in nature. We know that these properties make the virus very infectious, so if it came from nature, there should also be many animals infected with this, but we have still not been able to trace the virus in nature”, Sørensen also elaborated in last week's interview.
In the article Sørensen and his co-authors add additional context to how they believe the virus evolved through experiments in laboratories.
The authors do this by pointing to earlier and open articles by Chinese and American researchers, where the researchers demonstrate and discuss how they have manipulated new chimeraviruses into existence, with SARS-coronavirus as a starting point.
Sørensen and his co-authors point to four different research projects where the chronology of the creation of a new chimeravirus is documented.
The first of these is the research project led by the world-famous Chinese scientist Dr. Zheng-Li Shi and her colleagues at Wuhan Virology Institute in 2008, which “successfully demonstrated technical capabilities to interchange RBD’s between bat SARS-like and human SARS viruses”.
These findings made the exchange of properties between SARS-coronavirus possible, Sørensen and his co-authors argue.
Furthermore, Sørensen’s article points to the fact that Wuhan’s Virology Institute again in 2010 took part in gain-of-function experiments with international collaborators, where SARS-coronavirus was provided with additional properties that increase the virus’s ability to infect humans: “In 2010 scientists from the ‘Special Viruses’ section of the Wuhan Institute of Virology were engaged in ‘gain of function’ experiments, jointly with international collaborators, to increase SARS-CoV infectiousness for humans. They used an HIV pseudovirus to express seven bat ACE2 receptors and compared their binding properties to human ACE2 receptors in order to pick the best for further optimizing a SARS-like coronavirus’s ability to bind to human cells”, they write
In order to build further on this research, Shi and her colleagues sought help from American researchers.
“The Chinese originally lacked the technology and competence to grow and measure the development of the virus”, Sørensen argues.
However, according to Sørensen, Shi and her colleagues received help from the University of North Carolina at Chapel Hill in the US, where a human cell culture was made available for further research on SARS-coronavirus.
In the article, Sørensen and his co-authors write: “In 2015 scientists from the ‘Special Viruses’ section of the Wuhan Institute of Virology were engaged in ‘gain of function’ experiments jointly with a majority team from the University of North Carolina Chapel Hill. Together, they manipulated bat viruses to create a mouse adapted chimeric virus SHC014-MA15 which binds to and can proliferate on human upper airway cells (2B4 Calu-3 – a cell line contributed by Chapel Hill).”
Sørensen and his co-authors write that this work created “a chimeric virus with very high infectivity potential targeted to the human upper respiratory tract” and that what is being described is “in fact, precisely SARS-CoV-2 properties”, which is the virus that causes Covid-19.
Sørensen and his co-authors writes that “the 2015 authors were well aware that the chimeric virus which they had created was very dangerous because they discussed this fact”, but also explains that the creation of the chimeric virus of increased pathogenicity was not intentional “In vivo experiments at Chapel Hill replicated the chimeric virus in mouse lung which showed significant pathogenesis which was the opposite of what the team had expected (“the creation of chimeric viruses like SHC014-MA15 was not expected to increase pathogenicity”).
The chimeric virus SHC014-MA15 that was created as a part of the collaboration between the Wuhan Institute of Virology and University of North Carolina at Chapel Hill is however according to an article published Shan-Lu Liu et al still different from the Sars-Cov-2 virus with a “divergence in the genetic sequence of this construct with the new SARS-CoV-2 (>5,000 nucleotides)”, Shan-Lu Liu writes.
Professor Kristian Andersen at the department of immunology and microbiology at Scripps Research again refers to the study conducted by Shan-Lu Liu when he writes that “the genetic data irrefutably show that SARS-CoV-2 is not derived from any previously used virus backbone”.
Sørensen and his co-authors is however not convinced that the divergence between the chimeric SHC014-MA15 virus created in 2015 and the novel coronavirus Sars-Cov-2 is enough to eliminate the possibility of Sars-Cov-2 being another chimeric virus that builds on this research.
To establish a connection between the chimeric viruses engineered by the Wuhan Institute of Virology and the Sars-CoV-2 virus Sørensen and his co-authors points to events back in 2016 when a new coronavirus started to infect pigs in China. This disease named SADS ended up killing approximately 25 000 piglets. The epidemic was investigated by the researcher at the Wuhan Institute of Virology, and tested against all known receptors used by coronaviruses, but none of these worked.
Sørensen and his co-authors therefore draws the conclusion that “SADS is a CoV infection utilising new tissue-specific binding domains”, and argues that the Sars-CoV-2 coronavirus has attained directly or indirectly properties from the SADS virus that makes it possible for the virus to use new receptors to attach to human cells in the upper airways.
Hence the evolution of the Sars-Cov-2 virus is summarized by Sørensen and his co-authors as follows: “In 2008, Dr Zheng-Li Si and WIV colleagues successfully demonstrated technical capabilities to interchange RBD’s between bat SARS-like and human SARS viruses. Building upon this, the 2010 work (Hou et al, 2010) perfected the ability to express receptors on human cells. On these foundations, the central Gain of Function work that underpins the functionalities of SARS-CoV-2 took place, carrying the WIV spike and plasmid materials to bond successfully to a UNC Chapel Hill human epithelial cell-line.
This work produced a highly infectious chimeric virus optimised to the human upper respiratory tract. In convergent support of this hypothesis, both Lu and Jia have now, in January and April 2020, shown that SARS-CoV-2 has a bat SARS-like backbone but is carrying an RBD from a human SARS and Zhan et al have, like us, noted unusual adaption to humans from the first isolate.
In the 2015 Chapel Hill work it was only ACE2 receptors that were discussed. However, in 2018 Zhou P. et al demonstrated capabilities to clone other receptors like APN and DPP4 and to test and compare these against the (intestine) tissue specific SADS-CoV identified. Then, in the 2019-20 Covid-19 pandemic, profuse symptoms indicating compromise of the bitter/sweet receptors are reported. Taken all together, this implies that by employing insights gained after 2015, as just deduced, a further optimization of the 2015 chimeric virus for additional binding to receptors/co-receptors such as bitter/sweet specific upper airway epithelia receptors occurred. That would help to explain the otherwise puzzling high infectivity and pathology associated with SARS-CoV-2 and hence also help to explain the social epidemiology of its spread”.
The release of a potential pandemic pathogen from a laboratory is by many viewed as a too catastrophic event to even be considered.
However many scientists now argue that it has already happened. In 1977 the H1N1 influenza virus caused an epidemic in the Soviet Union and China. This rapidly spreading epidemic was almost entirely restricted to persons younger than 26 years of age. A common explanation for this oddity is that the epidemic was caused by a frozen version of the virus that circulated in the 1950s, and in some way or another escaped laboratory containment.
It is also a known fact that the SARS-coronavirus that caused the SARS epidemic in 2003 has escaped laboratories in South-East Asia on at least four occasions. In 2003 WHO issued a statement calling for increased safety measures in laboratories that handle SARS-coronaviruses highlighting the risk of lab accidents: “The possibility that a SARS outbreak could occur following a laboratory accident is a risk of considerable importance, given the relatively large number of laboratories currently conducting research using the SARS-CoV or retaining specimens from SARS patients. These laboratories currently represent the greatest threat for renewed SARS-CoV transmission through accidental exposure associated with breaches in laboratory biosafety”, the WHO stated.
The laboratory operated by the Wuhan Institute of Virology was however built to adhere to far stricter security protocols than the ones criticized by the WHO back in 2003, and became the first Chinese laboratory that operated at the highest level of biosafety (level 4), when it was inaugurated in 2015.
At the Wuhan Institute of Virology lead scientist dr. Shi Zhengli ferociously denies any possibility that the Sars-cov-2 virus is a lab escapee. In a rare interview with the Scientific American, Zhengli explains that “she frantically went through her own lab’s records from the past few years to check for any mishandling of experimental materials, especially during disposal. Shi breathed a sigh of relief when the results came back: none of the sequences matched those of the viruses her team had sampled from bat caves”.
“That really took a load off my mind”, she is quoted saying.
Dr. Zhengli has also published the genomic sequence of a new virus that her team had sampled in an abandoned mine shaft seven years ago that shares an overall genome sequence identity of 96.2% with the Sars-Cov-2 virus, the closest match so far according to her article.
However, concerns about the operational safety at the Wuhan Institute of Virology persist. In an article written by Josh Rogin at The Washington Post, Rogins refers to a leak embassy cable sent from the American Embassy in Beijing that raised on concerns about the safety routines at the Wuhan laboratory
“During interactions with scientists at the WIV laboratory, they noted the new lab has a serious shortage of appropriately trained technicians and investigators needed to safely operate this high-containment laboratory”, states the Jan. 19, 2018, cable, which was drafted by two officials from the embassy’s environment, science and health sections who met with the scientists at the Wuhan Institute of Virology.
On the 18-19th of May the WHO conducted its 73rd general assembly, and passed a resolution that “requests the Director-General, working with other organizations and countries, to identify the zoonotic source of the virus and the route of introduction to the human population”.
Sørensens and his co-authors argue that this investigation should not be limited to examining the origin of the Sars-Cov-2 virus solely based on the assumption of a zoonotic source.
The WHO investigation commenced on the 7th of July.
A full print of Sørensens article can be accessed through this link.