COVID, June 7: Since the beginning of the COVID-19 pandemic, there have been various hypotheses to explain the origins of SARS-CoV-2.
So far, none of these hypotheses has shown the origins of the virus. One of the first scenarios put forward — that the Wuhan seafood market allowed for a rapid dispersion of the virus — seems less certain now. After a year of intensive research, the virus has still not been identified in any animals.
Animal-human transmission, however, remains one of the strongest hypotheses explaining the appearance of the new coronavirus: the coronavirus was transmitted from bats to humans through an intermediate host. It would not be the first time this happened.
In the case of MERS-CoV (Middle East Respiratory Syndrome), camels likely served as the intermediate host. For SARS-CoV-2, pangolins, scaly anteaters sold illegally in the Wuhan market, maybe the host, although this hypothesis requires more convincing evidence.
I am a professor in the department of biological sciences at Université du Québec in Montréal, an expert in virology, particularly in human retroviruses, and inhuman coronaviruses.
The idea that SARS-CoV-2 had accidentally leaked from a maximum-security biological laboratory — biosafety level-4 (BSL-4) — at the Wuhan Institute of Virology (WIV) began to circulate soon after the onset of the pandemic.
The possibility resurfaced in recent weeks, placing Dr Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), in an embarrassing situation. Some newspapers assert that the United States was funding this research laboratory and claim that the projects being funded there focused on gain-of-function studies. An opinion piece published in the Wall Street Journal claims that NIAID may have supported some of these experiments that were underway at WIV.
Although there may be benefits to gain-of-function experiments, there are also risks.
So, what are gain-of-function studies? Although the term is sometimes used broadly to refer to “gain-of-function” studies of proteins, in medical terms, it is associated with research on viruses. The goal of gain-of-function research is to create a virus with new properties that make it more pathogenic or more transmissible to humans.
Research that is too dangerous?
However, the principle underlying gain-of-function research has been widely challenged over the past decade.
A classic and oft-cited example, which concerns many scientists, is Ron Fouchier and Yoshihiro Kawaoka’s research on the highly dangerous avian H5N1 influenza virus. Using a technique that passed the virus from one ferret to another many time over, these researchers were able to create an H5N1 influenza virus that could be transmitted to the species by aerosols.
The study was widely debated and the research was eventually put on hold. The US government even urged scientific journals not to publish its full results, arguing that the information could be used by bioterrorists. The research was resumed in 2013.
Gain-of-function research has the potential to help prevent animal-to-human transmission of a virus with pandemic potential. However, this type of research must be carried out in a highly secure laboratory, such as those known as BSL-4.
The Wuhan lab-leak hypothesis is revived
So, the hypothesis that SARS-CoV-2 originated in a leak from the Wuhan lab is now being taken seriously.
In a May 11 interview, Fauci called for a more thorough investigation into the origins of SARS-CoV-2. On May 26, U.S. President Joe Biden instructed his intelligence agencies to double-down on their investigation into a possible laboratory leak of the virus responsible for the current pandemic.
New evidence has also been put forward by different media outlets: the Wall Street Journal recently revealed that several WIV researchers became sick in the fall of 2019 with symptoms similar to “both COVID-19 and common seasonal illnesses,” and that at least three were hospitalized, adding support to the need to investigate whether the COVID-19 virus escaped from the Wuhan lab.
The WHO, Biden and Fauci, among others, are calling for further investigation of the hypothesis, and the gain-of-function studies on animal coronaviruses at WIV is central to these inquiries.
Although a piece of conclusive evidence on the origins of SARS-CoV-2 may never be obtained, the latest developments raise new concerns about gain-of-function experiments in general and may lead to a re-evaluation of both the experimental approach and the safety regulations of the laboratories that use it.