Despite a year and a half since the outbreak of the corona pandemic, we still don’t know exactly where the SARS-CoV-2 virus that caused the spread of COVID-19 came from. Until now, the dominant view has been that the virus “spreads” from bats to humans. But there are growing demands for the test over fears it may come from a laboratory in Wuhan, China, where the Covid first appeared in late 2019. So now the question is: what do we know for sure and what still need to be discovered?
We know that the sequence of the SARS-CoV-2 virus is similar to that of the bat corona virus. Several decades ago, its “ancestor” circulated in a bat population in South Asia. But many questions remain unanswered: We don’t know how the virus entered Wuhan, how it evolved to spread infection to humans, and under what circumstances it infected the first person in its path. And we do not know if for each of these stages, there was a human contribution (direct or indirect).
“There is a possibility of this virus leaking from the Wuhan laboratory”
The routes of animal transmission, in other words, the spread of the virus from animals to humans is now widely written around the world. Scientists even believe that it is a major mechanism for the spread of new viruses. But the fact that the pandemic started around a large virus research center specializing in the study of coronaviruses with epidemiological potential in humans – the Wuhan Institute of Virology – led to another hypothesis, that of the virus escaping from the distrust lab.
Laboratory accidents have already caused human infections, including the H1N1 influenza pandemic of 1977 which killed more than 700,000 people. Which theory is correct? In the absence of definitive evidence and without promoting conspiracy theories, it is necessary to engage in a serious international discussion on the origin of SARS-CoV-2. In the scientific community, the debate on the origin of SARS-CoV-2 began with the publication of two articles at the start of the pandemic. The first of these, dated February 19, 2020, was published in the scientific medical journal The Lancet.
The article, signed by 27 scientists, highlights the efforts of Chinese experts to identify the source of the pandemic and shares the results. The authors condemned “rumors and misinformation” about the origin of the virus, and said they strongly condemned “conspiracy theories which suggest that the origin of COVID-19 is not natural.” The authors based their opinion on previously published sequence data on the virus, but did not detail the scientific arguments supporting a natural origin.
“Genetic manipulation is not the only reason”
In March 2020, another article published in ‘Nature Medicine’ provided a series of scientific arguments in favor of the natural origin of the virus. The authors reasoned: the hypothesis of natural origin is plausible, because it is the general mechanism of emergence of corona viruses, to hypothesize the creation of a new virus from the available sequences of the sequence SARS-CoV-2 far from other known coronaviruses is linked. Its sequence shows no evidence of genetic manipulation in the laboratory. This latter argument can be questioned, as there are methods by which scientists can alter viral sequences without leaving a trace.
These include cutting the genome into fragments which can then be assembled or, more recently, using the ISA protocol, in which interconnected fragments naturally come together in cells by homologous recombination: A phenomenon in which two molecules of DNA exchange fragments. Moreover, genetic manipulation is not the only cause of accidents or laboratory leaks. Meanwhile, more than a year of intensive research to try to prove the animal scenario with respect to the virus has so far failed: all 80,000 animal samples from around 30 species have all tested negative.
The samples were taken from domestic animals and wild animals from different provinces of China. But it’s important to note that the large number of negative samples does not contradict the animal-based scenario of the virus. Early papers arguing for the theory of laboratory accidents received little attention, perhaps because they came from groups such as the “Bulletin of the Atomic Sciences”, which criticizes the technology, or from outsiders. such as the DRASTIC team (an acronym that stands for ‘Decentralized Radical Self-Reliance Investigation Group for COVID-19’). The group is made up of 24 self-proclaimed “Twitter spies” who are mostly anonymous with the exception of a few scientists who participate under their real names, the group formed on Twitter in 2020 who created SARS-CoV-2 for them- even A search mission was set.
The group’s information and arguments have been fully examined, taken up and developed by certain virologists, microbiologists and scientific communicators. In July 2020, Etienne Decroli, one of the authors of this article, co-wrote a scientific article discussing the possibility of a laboratory accident. The theory of laboratory leaks gained momentum after a paper signed by 8 scientists on May 13 in the journal Science called for a re-investigation into the origins of SARS-CoV-2. So is it possible? Several elements raise questions as to the origin of the virus. In particular, it has been proven that the Wuhan Institute of Virology manipulated a virus similar to SARS-CoV-2 collected in southern China.
Joint commission investigation failed to identify cause of pandemic
In addition to direct genetic manipulation, a laboratory accident can also result from an infection during a sample in nature or during experiments with a virus grown in laboratory cells or mice, not necessarily directly manipulating its genome. . How can we know for sure? Earlier this year, a joint commission of China and the World Health Organization (WHO) failed to identify the cause of the outbreak in an investigation, concluding that it was most likely original animal and that the possibility of a laboratory accident was very high. less. But WHO director-general Tedros Adhanom Ghebreyesus said there were still questions that “will need to be resolved through further study.”
To determine if SARS-CoV-2 originated in the lab, further investigation would be needed in which investigators would have access to sequence databases as well as various resources used by Chinese researchers, including lab notebooks, submitted projects, scientific manuscripts, viruses. sequences, order lists and biological analyzes. Unfortunately, SARS-CoV-2 sequence databases have been inaccessible to scientists since September 2019. In the absence of direct evidence, alternative approaches may provide additional information. By analyzing in detail the available sequences of coronaviruses like SARS-CoV-2, it is possible that the scientific community can reach a consensus based on solid clues, as it has done in other pandemics, including the 1977 H1N1 virus.
Virginie Courtier, University of Paris and Etienne Dicroli, University of Aix-Marseille (AMU)