The return of the lab-leak theory

When the World Health Organization team tasked to investigate the origins of the COVID-19 pandemic reported its findings in March this year, one of its aims appeared to be to dismiss all speculation that the virus had been engineered by scientists engaged in “gain-of-function” experiments at the Wuhan Institute of Virology. It was “extremely unlikely,” the team said, that the virus had leaked from the laboratories in Wuhan.

The WHO delegation confirmed initial conjectures that the coronavirus SARS-CoV-2 came from horseshoe bats, and transferred to wildlife species sold at the Wuhan wet market. These bats are fairly common in Hubei province and countries like Cambodia and Thailand.

But, the expert team failed to establish which animal species the virus had jumped to, and how it found its way to humans. Up to now, no one has found SARS-CoV-2 anywhere but in humans. This “missing link” weakens the theory of zoonotic transfer. Chinese state media are promoting the counter-narrative that the virus may, in fact, have originated elsewhere and found its way to China through frozen food imported from abroad.

For as long as Donald Trump was US president, Western liberal media generally refrained from lending credence to the idea of a genetically-engineered pathogen escaping from a Chinese lab. Behind the reticence was the fear that it might energize the conspiracy theories and China-bashing popular among Trump’s populist supporters. The real-life consequences of such beliefs are distressingly mirrored in the racist hate they have spawned against Asians in general.

But, neither science nor mass media can remain indefinitely quiet on even politically explosive questions. A year ago, Dr. Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, said that “everything about the stepwise evolution over time strongly indicates that [this virus] evolved in nature and then jumped species.” But, in May 2021, he was asked if he was still certain it developed naturally. His answer was terse but telling: “No, actually.”

WHO director-general Tedros Adhanom Ghebreyesus himself noted: “I do not believe this investigation is extensive enough.” This view found echoes in a recent letter sent to the journal Science by 18 scientists, including prominent names in virology. Without advancing any theory, these experts sought the reopening of the WHO investigation. Bewailing the cavalier dismissal of the lab-leak theory, they wrote that “theories of accidental release from a lab and zoonotic spillover both remain viable.”

Some of the signatories were scientists who continued to believe that the novel coronavirus naturally evolved from wildlife, and who thought that retrofitting a virus strain in the lab to become the highly transmissible and deadly SARS-CoV-2 would have been an exceptional achievement in genetic re-engineering. But they were unified in the consensus that the WHO investigation should have included a comprehensive evaluation of biosafety measures at the Wuhan Institute of Virology.

As rare as they may be, laboratory accidents do happen. Lab technicians may be exposed to all kinds of pathogens in the course of their work. Worse, they can unsuspectingly pass on the infection to the larger population. These concerns are real enough to generate an ethical conundrum that prompted the Obama administration in 2014 to suspend federal funding for cutting edge “gain-of-function” studies. The suspension was lifted during the Trump presidency.

One of the active voices in that debate was that of Prof. Marc Lipsitch of the Harvard TH Chan School of Public Health. In an online article titled “Why Do Exceptionally Dangerous Gain-of-Function Experiments in Influenza?” published shortly before the COVID-19 pandemic, Lipsitch made a forceful case against research that involved the manipulation of viruses to create what he calls “potential pandemic pathogens” (PPPs). Such experiments, he argued, “are nearly unique in that they present biosafety risks that extend well beyond the experimenter or laboratory performing them; an accidental release could … lead to global spread of a virulent virus, a biosafety incident on a scale never before seen.”

Lipsitch disputes the value of these studies to basic science and public health, arguing that there are safer alternative ways of answering the questions they pose. Whatever residual benefits they may have, he writes, are outweighed by the risks they present to humankind. In gain-of-function experiments, a starting virus strain, e.g. of influenza H5N1, is modified through targeted mutations, or coinfection, or spontaneous mutation. The idea is to induce the formation of phenotypes or characteristics, like higher transmissibility, when the modified pathogen is transferred to recipient animals. Such studies are supposed to help public health authorities anticipate the evolution of deadlier viruses in nature, and guide the development of vaccines and therapeutics.

The wisdom of such scientific projects has been repeatedly questioned, not only for the risks posed by lab leaks, but also in view of their potential replicability by bioterrorists who may gain easy access to published results. This debate will no doubt haunt the scientific community for a long time. But, it’s almost certain that, one of these days, a team of legitimate scientists will come forward to make the shocking claim that they have evidence to prove the pathogen behind COVID-19 was created in a laboratory. I dare not think what happens next if their findings gain traction.