Scientists in several countries are calling for a serious investigation into the beginnings of SARS-CoV-2, the novel coronavirus that gave rise to the covid-19 pandemic. In an open letter released Thursday, the group says that there are still too many unanswered questions about how the pandemic started and that the so-called “lab-leak” theory remains plausible, as does the natural origin theory.
In early February, the World Health Organization unveiled the preliminary results from their investigation into the start of the pandemic back in December 2019, which involved researchers traveling to some of the first known areas of transmission in Wuhan, China. The team did not rule out the possibility that the virus reached the human population through a release from a nearby virology lab, but they called it ‘extremely unlikely.’ The most likely explanation, they concluded, was that the virus had jumped from animals (probably bats) to humans, possibly through an intermediate host like pangolins.
Even at the time, the WHO’s conclusions were not likely to be universally embraced. Some polls suggest that a sizable number of people continue to believe that the virus was deliberately created as a bioweapon and released into the wild. Yet other people, including the former head of the CDC—Robert Redfield—instead posit that the virus may have simply leaked from a lab without malicious intent. In this theory, the leaked virus may have been manipulated in the lab beforehand, but it could have also just come in from the wild and then reached people without being changed in any way.
Many scientists have criticized the more fantastical versions of these theories, providing evidence that there’s nothing inherently suspicious about the genetics of SARS-CoV-2 that would suggest it was created as a bioweapon. They also point out that viruses routinely jump from one species to another, so it’s completely plausible that the pandemic could have started as one of these zoonotic events.
The authors of this new letter, published in Science, don’t dispute these points. But they say it’s too early to close the door on the lab leak theory, not without more evidence. “Theories of accidental release from a lab and zoonotic spillover both remain viable,” the authors wrote.
Their main point is that not enough work has been done to truly call the lab leak theory extremely unlikely. As evidence, they cite WHO Director-General Tedros Ghebreyesus himself. In his closing remarks following the final release of the WHO team’s findings in late March, Ghebreyesus said that their investigation into the possibility of a lab accident wasn’t extensive enough and that “further data and studies will be needed to reach more robust conclusions”—studies that he would be willing to deploy more resources toward.
The enduring suspicion of a lab leak being the impetus for the pandemic isn’t entirely about the science either, but the politics of the country where it emerged. China is notorious for censoring unflattering information about the government, often to the point of silencing their own citizens. Irrespective of its true origins, China did try to limit information about the pandemic early on, including from doctors and scientists who tried to warn the world about the potential threat of covid-19. And the country also imposed restrictions on the WHO investigators sent into Wuhan.
The authors hail from universities and research institutions in the US, UK, and Switzerland, including Harvard, MIT, and the University of Cambridge. And they say that only a truly impartial investigation will be able to clear the air over how covid-19 came to be. Until that’s possible, neither theory about the virus should be dismissed out of hand.
“We must take hypotheses about both natural and laboratory spillovers seriously until we have sufficient data,” they wrote. “A proper investigation should be transparent, objective, data-driven, inclusive of broad expertise, subject to independent oversight, and responsibly managed to minimize the impact of conflicts of interest.”