The SARS-CoV-2, the Covid-19 virus, has caused the biggest pandemic in the past hundred years. Understanding its origins is therefore crucial to elucidate what happened at the end of 2019 – and prepare for the next viral pandemic.
Studies of this type take time, require organization and cooperation. Moreover, they must be guided by scientific principles, and not by political motives or posture. However, for various reasons, the ongoing investigation into the origins of SARS-CoV-2 has already taken too long: the first cases were reported in Wuhan, China, in December 2019, more than twenty months ago.
As reported by various media, on August 24, US intelligence agencies transmitted to President Joe Biden the results of their research into the emergence of the epidemic. (A summary of this work was declassified and made public a few days later, editor’s note.)
According to a preliminary account published in the New York Times, the investigation does not yet determine whether the spread of the virus followed a laboratory accident or proceeded from a natural emergence involving a passage of the animal. to human beings.
If the possibility of a laboratory leak remains an avenue to be explored (on condition that it can be scientifically substantiated), it should not distract attention from the other hypothesis which, based on the data currently available, should mobilize most of our energy. Indeed, the more time passes, the less the experts will be able to determine the biological origins of the virus.
The laboratory accident hypothesis remains very popular in the media. However, it is not the most scientifically supported (Wuhan P4 laboratory, here in 2020). | Hector Retamal / AFP
Six recommendations for further investigation
I am one of the experts who left for Wuhan at the beginning of the year as part of the World Health Organization (WHO) investigation intended to shed light on the question of the origin of SARS-CoV- 2. We found that the available evidence clearly indicates that the pandemic began as a result of “zoonotic” transmission of the virus, that is, transfer from animals to humans.
Our investigation resulted in a report, published in March 2021, in which we make several recommendations for further work to be considered. It is now urgent to get down to designing the scientific studies that will allow them to be carried out successfully.
On August 25, with other editors of this report, we published an article in the journal Nature to argue in this direction. We are wasting precious time, which could be devoted to deepening six lines of research in order to learn more about the origin of the coronavirus. These areas, which we believe are priorities, are as follows:
Additional traceability studies, based on initial reports of the disease;
Investigations aimed at analyzing the specific antibodies to SARS-CoV-2 developed by patients living in regions where the first cases of Covid-19 occurred. This is important, because in many countries (including Italy, France, Spain and the United Kingdom), the evidence that would have supported cases of early detections of the coronavirus has turned out to be inconclusive;
Traceability surveys carried out in communities that had relationships with the wildlife farms that supplied Wuhan’s markets;
Studies designed to assess the risks represented by potential host animals. It can be the primary host (such as bats), secondary hosts or animals which would have played the role of enhancers;
Detailed analyzes of risk factors for early outbreaks, wherever they have occurred;
The follow-up of any new credible leads.
A race against time is underway
Time is of the essence in the feasibility of some of these studies. It is known, for example, that anti-SARS-CoV-2 antibodies thus appear about a week after a person has been infected with the virus and has recovered, or after having been vaccinated. But their concentration decreases over time – analyzing samples taken now from people who were infected in December 2019 or even before, could prove more difficult, and this problem will not improve as the disease progresses. time will pass.
Relying on the analysis of antibodies present in the general population to differentiate between vaccination, natural infection or secondary infection (especially if the initial infection occurred in 2019) is also problematic. For example, after infection with the virus, a range of antibodies specific for SARS-CoV-2, directed against the Spike protein or against the nucleoprotein, is detectable for varying times, at varying concentrations and according to neutralizing capacities. coronavirus variables as well. In the case of vaccination, depending on the vaccine used, only antibodies to the Spike protein may be detected, which also decrease over time.
An international consensus regarding the detection methods used in the laboratory is also necessary. In recent months, differences in the analysis protocols used have indeed given rise to discussions on the quality of the data collected in various parts of the world. However, reach an agreement on the laboratory techniques to be implemented in serological and genomic studies, as well as on access to samples and their sharing (while taking into account questions of consent and respect for privacy) takes time.
And it also takes time to get funding. For all of these reasons, time is a resource we cannot afford to waste.
The constraints of the field
In addition, in Wuhan, many wildlife farms have closed following the initial outbreak, usually without any control. With the resulting dispersal of animals and humans, it is increasingly difficult to find biological evidence in either side of the early spread of the coronavirus.
Fortunately, some analyzes can still be carried out. Among them is the review of initial case studies, and studies of blood donors in Wuhan and other Chinese cities (as well as in all places where viral genomes were detected early).
It is important to analyze the progress or the results of these studies carried out by local and international experts, but no mechanism allowing this type of verification has yet been put in place.
Many analyzes can still be carried out, on the population, but also on old samples preserved (tests in a laboratory in Wuhan, August 2021). | AFP
Since March and the publication of the WHO report, new elements have emerged. These, like the data in our report, have been reviewed by independent scientists. They came to conclusions similar to those of the WHO document, namely:
the natural reservoir of SARS-CoV-2 has not yet been identified;
key species (in China or elsewhere) may not have been tested;
there is substantial scientific evidence supporting the zoonotic origin of the pandemic.
A step forward, a step to the side …
While the possibility of a laboratory accident cannot be completely ruled out, it is highly unlikely, given the repeated human-animal contact that regularly occurs in the wildlife trade.
However, the hypothesis of the coronavirus escaped from a laboratory continues to arouse the interest of the media, despite the available evidence … These discussions, more political than scientific, still slow down the cooperation and obtaining the agreements necessary to advance the studies required by the second phase of the WHO report.
The World Health Organization has called for the creation of a new committee to oversee future studies on the origins of the SARS-CoV-2 coronavirus. The initiative is commendable, but it risks causing further delay in the planning envisaged for the said studies …
This article is republished from The Conversation under a Creative Commons license. Read the original article.