Two clues COVID may have come from lab
A growing number of scientists are raising the possibility COVID-19 was created in a laboratory, saying the option cannot be ruled out.
Leading immunologists and geneticists have told Sky News that there are two unusual things about COVID-19 that open the door to it being man-made rather than a naturally-occurring virus.
The first curious characteristic of COVID-19 is that the virus binds to human ACE2 receptor cells more strongly than it does to any other animal, including bats.
The second unusual thing about the virus that causes COVID-19 is that it has what's called a "furin cleavage site" that its closest genetic bat-coronavirus relative, RaTG-13, does not have.
This site makes it significantly more infectious.
Israeli geneticist, Dr Ronen Shemesh, who is working on a treatment for COVID-19, said in his opinion the virus was more likely created in a laboratory than evolved in nature.
"There are many reasons to believe that the COVID-19 generating SARS-CoV-2 was generated in a lab. Most probably by methods of genetic engineering," he told Sky News.
"I believe that this is the only way an insertion like the furin protease cleavage site could have been introduced directly at the right place and become effective."
Dr Shemesh points to the insertion of a furin site as the most unusual aspect of COVID-19.
"I believe that the most important issue about the differences between all coronavirus types is the insertion of a furin protease cleavage site at the spike protein of SARS-CoV-2," he said.
"Such an insertion is very rare in evolution, the addition of such four amino acids alone in the course of only 20 years is very unlikely."
Dr Shemesh, who has a PhD in genetics and molecular biology from the Hebrew University in Jerusalem, and over 21 years of experience in the field of drug discovery and development, said it is even "more unlikely" that this insertion happened in exactly the right place of the cleavage site of the spike protein - which is where it would need to occur to make the virus more infectious.
"What makes it even more suspicious is that fact that this insertion not only occurred on the right place and in the right time, but also turned the cleavage site from an serine protease cleavage site to a furin cleavage site," he said.
"This protein cleaving protein is highly promiscuous, it's found in many human tissues and cell types and is involved in many other virus types activation and infection mechanisms (it is involved in HIV, herpes, ebola and dengue virus mechanisms).
"If I was trying to engineer a virus strain with a higher affinity and infective potential to humans, I would do exactly that: I would add a furin cleavage site directly at the original less effective and more cell specific cleavage site."
La Trobe University Chemistry and Physics Professor David Winkler said there were several possibilities for the source of COVID-19 and you cannot rule out the laboratory as one option.
"On the basis of the calculations we've done, you can't exclude that it's been processed through human cells in a biosecurity lab - but it's certainly not the only explanation," he said.
Flinders University Professor Nikolai Petrovsky says COVID-19 is "exquisitely adapted to infect humans".
"We really don't know where this virus came from - that's the truth. The two possibilities is that it was a chance transmission of a virus … the other possibility is that it was an accidental release of the virus from a laboratory," he said.
"One of the possibilities is that an animal host was infected by two coronaviruses at the same time and COVID-19. The same process can happen in a petri-dish.
"In other words COVID-19 could have been created from that recombination event in an animal host or it could have occurred in a cell-culture experiment.
"I'm certainly very much in favour of a scientific investigation. Its only objective should be to get to the bottom of how did this pandemic happen and how do we prevent a future pandemic."
Broad Institute of MIT and Harvard and University of British Columbia biologist, Alina Chan, said there was little evidence to definitively say where COVID-19 originated.
Dr Chan said there is no current evidence to show that the coronavirus originated in the Wuhan wet market.
"If intermediate animal hosts were present at the market, no evidence remains in the genetic samples available," she said.
"There is no publicly available genetic evidence of cross-species transmission at the Hunan seafood market. But at the same time we cannot rule out the Hunan seafood market because we have not been able to analyse other data, eg, animal samples, from the market."She said human adaptation in nature and in a laboratory is possible.
"Did SARS-CoV-2 transmit across species into humans and circulate undetected for months prior to late 2019 while accumulating adaptive mutations?" she said.
"Or was SARS-CoV-2 already well adapted for humans while in bats or an intermediate species?"
Originally published as Two clues COVID may have come from lab