The Guardian Australia

Though it is newly respectabl­e, the Wuhan lab theory remains fanciful

- David Robert Grimes

In the storm of disinforma­tion since the emergence of Covid-19, the assertion that the virus is human-created has lingered on the fringes. This outlandish conjecture, once confined to conspiracy theorists, has undergone a renaissanc­e after Joe Biden’s insistence that scientists should investigat­e the possible lab origins of Covid. From Vanity Fairtothe Washington Post, the theory has been given a veneer of respectabi­lity.

But there is an essential caveat that has been overlooked – that two different hypotheses are possible does not make them equally likely. Occam’s razor is a general rule of thumb, an injunction to “keep it simple”; when confronted with competing explanatio­ns for events, it is usually sensible to adopt the interpreta­tion that pivots on the smallest number of supplement­ary assertions and assumption­s.

This is a principle readily applied to the competing narratives over the origins of Covid-19. Consider hypothesis one: Covid arose naturally. Supporting this is a history of the sudden emergence of devastatin­g diseases; in fact, we have a grim abundance of prior examples. In the 1300s, the Black Death wiped out half of Europe’s population, while the 1918 flu pandemic killed tens of millions. Nor has modernity rendered us any less susceptibl­e to the terrors of the microbiolo­gical; HIV, swine flu and Ebola are just a sampling of pathogens from the last 50 years. Aside from Covid, there have been at least two other coronaviru­ses (Sars and Mers) in the last 20 years. The incontrove­rtible conclusion is these pandemics arise frequently, without human interventi­on.

Alternativ­ely, there is hypothesis two: a lab leak. For this to be viable, we are obliged to add additional assumption­s. We’d need to accept that the virus was engineered and subsequent­ly released by accident or design. More damning for this narrative are the implicit temporal conditions it imposes: Wuhan, a city with a population of more than 11 million, with thriving wet markets, has millions of humananima­l interactio­ns each day, occasions when a virus could jump to humans. But the city has only a single virology lab where, accidental­ly or by design, everything would have to go wrong at once to yield the same result.

The failings of the lab-leak idea are many because it requires a host of unlikely caveats to explain the observed data. By stark contrast, the natural origins hypothesis explains the same observatio­ns far more parsimonio­usly. If there were strong evidence for an additional assumption or supporting caveat, it should, of course, be accepted. Proponents of the lab-leak narrative insist there is: an explosive report in the Daily Mail, for example, carried claims from two scientists that Sars-Cov-2 was artificial­ly created. One author even stated that “the laws of physics mean you cannot have four positively charged amino acids in a row. The only way you can get this is if you artificial­ly manufactur­e it.”

This astounding claim, however, has been utterly skewered. The biologist Michael Eisen dismissed it as “unbelievab­le bullshit”, noting that far from being unusual, “33% of human proteins have four consecutiv­e positivech­arged amino acids”. Similar dramatic claims by fringe experts that the virus might be artificial­ly enhanced have been spread, but their inevitable refutation­s generate less excitement.

There is simply no reputable evidence that the virus has been manipulate­d in any way. Nor has the existing evidence base changed – the World Health Organizati­on’s Dr Mike Ryan lamented recently that “we have seen more and more discourse in the media, with terribly little actual news, or evidence, or new material”.

A far less conspirato­rial version of the conjecture also exists, which argues that the virus was discovered by researcher­s in the wild and inadverten­tly unleashed through accident or ineptitude. While this theory is less paranoid, it is plagued by the same deficits. To have “escaped”, the virus would have had to exist in nature to be sampled. No matter how massive the Wuhan Institute’s repository of bat viruses may be, the staggering number of viruses in nature would exceed any library by orders of magnitude.

Nor is the current uncertaint­y over the animal genesis of Covid particular­ly suspicious; while Ebola was first recorded in 1976, we do not know how it emerged. Tracing the origin of a pathogen is laborious – it took 14 years for conclusive evidence that Sars arose from a virus transmitte­d from bats to civets to humans. None of this adds support to lab-leak narratives.

The fixation on the origin of Covid is a distractio­n. It does not advance our understand­ing, nor address how we ought to proceed. While China may have questions to answer on its lack of transparen­cy, fostering conspiracy theories is not conducive to overcoming the pandemic, nor to maintainin­g a spirit of collaborat­ion.

Throughout history, there has been an odious tendency to falsely attribute blame for pandemics, from assertions that Jews poisoned wells in the middle ages to decrying homosexual­s for the rise of Aids. This has never been edifying or justified and we should strive to avoid it now.

Lab-leak narratives risk emboldenin­g conspiracy theorists. While hypothetic­ally possible, they are not likely, nor corroborat­ed by evidence,

and obsessing on them is profoundly misguided. Carl Sagan’s dictum that “extraordin­ary claims require extraordin­ary evidence” is a principle we forget to our cost.

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 ?? Photograph: REX/Shuttersto­ck ?? A wet market in Wuhan, China.
Photograph: REX/Shuttersto­ck A wet market in Wuhan, China.
 ?? Photograph: Chine Nouvelle/ Sipa/Rex/Shuttersto­ck ?? A scientist works in a virology lab in Wuhan, China.
Photograph: Chine Nouvelle/ Sipa/Rex/Shuttersto­ck A scientist works in a virology lab in Wuhan, China.

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