Lab of natuur?

Is het SARS-CoV-2 virus nu ontstaan in de natuur en op een markt in Wuhan overgesprongen op mensen? Of is het geconstrueerd door mensen en ontsnapt uit een laboratorium in Wuhan? Dit is het meest grondige artikel dat ik tot nu toe heb gezien. Hier de globale conclusie, maar wat dit verhaal zo boeiend maakt is de gedetailleerde bespreking van bewijs voor het een en het ander.

De conclusie: onderzoekers aan het Wuhan Virologie Instituut waren bezig – met subsidie van het Amerikaanse NIAID overheidsinstituut – met experimenten om coronavirussen besmettelijker te maken. (Die subsidie was aangevraagd en verkregen door een organisatie geleid door Peter Baszak, die later een open brief organiseerde in The Lancet waarin vijf virologen met grote stelligheid schreven dat het virus niet was ontsnapt uit een laboratorium in Wuhan.) De onderzoekers waren niet gevaccineerd (want er bestond toen nog geen vaccin) en hielden zich niet aan de maximale veiligheidseisen (beaamd door het hoofd van het onderzoek in een interview) die waren voorgeschreven voor riskant onderzoek (want te veel gedoe met maanpakken en controles.) Het virus was al helemaal aangepast aan mensen, terwijl virussen in de natuur allerlei mutaties ondergaan voordat ze effectief worden. Het SARS2 virus heeft een ongewone structuur, een ‘furin cleavage site,’ die geen enkel ander beta-coronavirus heeft. Bij SARS1 en MERS-virussen waren uitgebreide sporen teruggevonden in de natuur en werd de eerste ‘doorgever/ontvanger’ gevonden. Bij SARS2 niet. (tip J. Meischke)

Hier enkele opmerkelijke alinea’s uit het stuk:

‘What became clear was that the Chinese had no evidence to offer the commission in support of the natural emergence theory.

This was surprising because both the SARS1 and MERS viruses had left copious traces in the environment. The intermediary host species of SARS1 was identified within four months of the epidemic’s outbreak, and the host of MERS within nine months. Yet some 15 months after the SARS2 pandemic began, and after a presumably intensive search, Chinese researchers had failed to find either the original bat population, or the intermediate species to which SARS2 might have jumped, or any serological evidence that any Chinese population, including that of Wuhan, had ever been exposed to the virus prior to December 2019.’

(…)

‘Researchers at the Wuhan Institute of Virology, led by China’s leading expert on bat viruses, Shi Zheng-li or “Bat Lady,” mounted frequent expeditions to the bat-infested caves of Yunnan in southern China and collected around a hundred different bat coronaviruses. Shi then teamed up with Ralph S. Baric, an eminent coronavirus researcher at the University of North Carolina.

(…)

‘So who else, besides miners excavating bat guano, comes into particularly close contact with bat coronaviruses? Well, coronavirus researchers do. Shi says she and her group collected more than 1,300 bat samples during some eight visits to the Mojiang cave between 2012 and 2015, and there were doubtless many expeditions to other Yunnan caves.

‘Imagine the researchers making frequent trips from Wuhan to Yunnan and back, stirring up bat guano in dark caves and mines, and now you begin to see a possible missing link between the two places. Researchers could have gotten infected during their collecting trips, or while working with the new viruses at the Wuhan Institute of Virology. The virus that escaped from the lab would have been a natural virus, not one cooked up by gain of function.’

(…)

‘…the long history of viruses escaping from even the best run laboratories. The smallpox virus escaped three times from labs in England in the 1960’s and 1970’s, causing 80 cases and 3 deaths. Dangerous viruses have leaked out of labs almost every year since. Coming to more recent times, the SARS1 virus has proved a true escape artist, leaking from laboratories in Singapore, Taiwan, and no less than four times from the Chinese National Institute of Virology in Beijing.

(…)

‘In the case of SARS1, researchers have documented the successive changes in its spike protein as the virus evolved step by step into a dangerous pathogen. After it had gotten from bats into civets, there were six further changes in its spike protein before it became a mild pathogen in people. After a further 14 changes, the virus was much better adapted to humans, and with a further four, the epidemic took off.

But when you look for the fingerprints of a similar transition in SARS2, a strange surprise awaits. The virus has changed hardly at all, at least until recently. From its very first appearance, it was well adapted to human cells.’

(…) The direct-from-bats thesis is a chimera between the natural emergence and lab escape scenarios. It’s a possibility that can’t be dismissed. But against it are the facts that 1) both SARS2 and RaTG13 seem to have only feeble affinity for bat cells, so one can’t be fully confident that either ever saw the inside of a bat; and 2) the theory is no better than the natural emergence scenario at explaining how SARS2 gained its furin cleavage site, or why the furin cleavage site is determined by human-preferred arginine codons instead of by the bat-preferred codons.’