By Robert Hickson 16/05/2021

In books and movies it is often a good plot point for a disease (or monster) to escape, accidentally or with assistance, from a government lab. There are also real cases of pathogens getting out of labs (but quickly being controlled).

That’s also a discussion going on now about Covid-19. Natural evolution or human agency? Spillover or accident? The origin of SARS-CoV-2 still isn’t definitive. A letter published last week in Science from some leading public health and infectious disease researchers calls for greater scrutiny of the possibility that the SARS-CoV-2 pandemic resulted from an accidental release from a lab.

The World Health Organisation investigation earlier this year concluded that a laboratory escape as the source was “extremely unlikely.” But the authors of the Science letter point out that assessment received less consideration than infection from a wild or captive animal, and that independent access to information from China did not occur. They note too that the Director General of the WHO thought the report did not contain an adequate assessment of the possibility of laboratory escape.

The letter does not claim that the pandemic started due to a virus escaping from a research lab. Their point is that greater scrutiny of this possibility is still required, to both understand the origin and to help reduce the risks of further pandemics.

That’s a reasonable stance to take.


Was it a lab leak?

The possibility of a lab escape is examined  by science writer Nicholas Wade in a long article in The Bulletin of the Atomic Scientists. While he looks at both hypotheses, he clearly thinks there is more to support the lab escape hypothesis.

The Public Health Expert blog republished a blog post that considers Wade made a good case. Too uncritically in my view.

Although Wade highlights some important issues, I think he abandons a dispassionate  journalistic approach for an, at times, conspiratorial one. He refers to “the virologists’ omertà”, where there is a supposed code of silence by virologists to not mention genetic experiments for fear of jeopardising reputations and funding opportunities. And he suggests that science journalists are naïve, taking scientists at their word. These assertions are ingenuous and he offers opinions not evidence.

There has been plenty of robust scientific and journalistic challenging during the pandemic. For example, early debates about how contagious and serious the SARS-CoV-2 is, the benefits and risks of encouraging herd immunity, the robustness of particular therapeutic trials, and whether the D614G mutation conferred greater transmissibility.

Science writers like Zeynep Tufekci (an Associate Professor at the University of North Carolina) and Ed Yong at The Atlantic, Carl Zimmer at the New York Times and Kai Kupferschmidt at Science magazine have written critically and insightfully about the pandemic. (Yes, these are all US publications, but these are where I’ve seen some of the best science journalism on Covid-19).


Possibilities aren’t facts

Wade’s article, like many conspiracy-related theories, emphasises how many things seem very unlikely to have occurred naturally. Such as, not having found the ancestral virus in the wild as quickly as for SARS, the virus apparently being well adapted to infect humans, the unusual furin cleavage site.

And he notes the research interests and earlier reports of safety concerns at the Wuhan Institute of Virology. Taken together these make it seem to him that a lab escape is more likely. But that is just assertion not evidence.

While he refers to some scientific papers to support his views, he ignores others that don’t. Such as some noting the diversity in bat coronaviruses, and the frequency of recombination in coronaviruses and occurrence of similar cleavage sites in other human coronaviruses.

To be fair, researchers have sometimes too quickly asserted that laboratory escape is unlikely. Escapes of pathogens from labs do occassionaly happen. So, it is not cut and dried how the virus started circulating in Wuhan.

Wade does highlight important issues about gain-of-function experiments (where viruses are modified to see if they are able to infect new hosts). This was covered in more detail by science journalists last year, but probably not as widely read.


Gather evidence not assertions

Further investigation of the origin of the pandemic is necessary. There are still critical gaps in knowledge about the virus’ origins, so jumping to one conclusion or another now isn’t helpful or productive.

This also shouldn’t stop or hinder improving approaches to evaluating zoonotic risks in the wild. Or to improving regulation and oversight of high-risk research.


Photo by Marija Zaric on Unsplash