Doctors, WHO scientists and all public health organizations kept telling us this. We are on the brink of a devastating global pandemic. The question that no one can answer is that of the source of this expected and almost certain disease. Will it be Ebola, Zika or Nepah as originally feared? Or the Chinese coronavirus that is now shaking the world? This virus appears to be a very serious candidate for triggering a global pandemic. Especially since scientists are almost unanimous: the next global pandemic will be spread through the respiratory tract; it will be a priori non-lethal, but caused by a virus, which spreading all over the world, would cause a hecatomb.
The data from the World Health Organization (WHO) are conclusive: the probability of a pandemic emerging is increasing. Every day we learn of the existence of a new pathogen, while the world's population continues to grow and the interconnections across the planet are becoming increasingly dense. A meeting of parameters that would favour the outbreak and spread of a devastating disease.
According to the World Health Organization, a global pandemic could erupt at any time. What disease is it? Could it be a as yet unknown disease that the WHO refers to as "disease X", a mysterious pathogen that has not yet been discovered but whose threat is imminent and seemingly inevitable? A danger included in the list of the most dangerous epidemics, in the same way as Ebola, haemorrhagic fever, the respiratory syndrome coronavirus (MERS), severe acute respiratory syndrome (SARS) or the Zika virus.
No one knows yet where this disease might come from. A multitude of possible sources have been identified. It could be a mutation of an existing virus, a virus that escaped from a laboratory, a terrorist risk. It could also be a zoonosis, an animal-to-human transmission. 70% of newly discovered diseases have come from animal sources, whether domestic or wild. The Chinese coronavirus bears an uncanny resemblance to the picture painted by researchers and the WHO.
"Global Catastrophic Biohazard"
A team of scientists from the Johns Hopkins Center for Health Security shed a striking light on this mystery. They published a report entitled "The Characteristics of Pandemic Pathogens", which established a framework for identifying naturally occurring microorganisms that pose a "global catastrophic biological risk" (GCBR in the terminology of public health experts).
GCBRs" are events in which biological agents could lead to a sudden, extraordinary and widespread disaster beyond the collective capacity of national and international governments and the private sector to control it. There is no comprehensive catalogue of GCBR culprits, forcing the health security community to rely only on historical examples (such as the 1918 Spanish Influenza) to guide its preparedness priorities.
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Yet Dr. Amesh Adalja, project leader and senior researcher at the Johns Hopkins Center warned: " Health security preparedness must be adaptable to new threats and not be based exclusively on historical concepts. ». Another pitfall to be avoided, scientists say, is that of focusing on viruses with a high mortality rate such as Ebola or Zika. As soon as they appear in any part of the world, a general uproar is mobilized to fight them. On the other hand, their high mortality rate works against them. By killing their hosts, these viruses are usually driven to extinction before the pandemic stage. The fight against these terrible diseases should not be neglected, but researchers at the John Hopkins Center fear that this may miss the real danger presented by "secondary" diseases which, with the help of a few mutations, can become potentially pandemic.
Researchers are thus breaking down a preconceived idea: the next pandemic will not come from a virus with a high mortality rate, but from a common virus, the family of those that assail us in winter, such as common rhinoviruses or coronaviruses for example. They are not very deadly but their pandemic potential is enormous. Indeed, the authors point out that in order to destabilize governments, the economy, societies, and all health organizations, mortality is less important than a very high rate of people being sick at the same time. There is evidence that a virus that is not very deadly but highly contagious, especially through the airways, can eventually cause a mass death. This was the case with the Spanish flu (H1N1) which occurred between 1918 and 1919. The virus had a mortality rate of only 2.5 %. Yet its transmission in the air allowed the contagion of hundreds of millions of people worldwide, leading to more than fifty million deaths.
Pandemic agent profile
To reach this conclusion, the researchers led by Amesh Adalja reviewed the literature and published reports on the characteristics of emerging infectious diseases, the pathogenic potential of a host of microorganisms: bacteria, fungi, prions, viruses, protozoa, etc.; interviewed more than 120 technical experts from academia, industry and government; and finally convened a meeting of a subset of these experts to discuss the preliminary analysis of the information gathered by the team. The result is a composite picture of the future pandemic agent.
Its mode of transmission, the team concluded, will most likely be respiratory. It will be contagious during the incubation period, before the onset of symptoms, or when infected individuals show only mild symptoms. Finally, it will require factors specific to the host population (e.g. people not immune to it) and other characteristics of intrinsic microbial pathogenicity (e.g. a low but significant case-fatality rate), all of which together greatly increase the spread of the disease and infection. Among the criteria, the researchers add that this pathogen is distinguished by the fact that no direct treatment or prevention method exists to date against it.
The great pandemic that is expected would therefore come from a virus that appears benign but mutates easily to acquire maximum harmfulness. In possession of this sketch, the authors of the report called for a different perspective in our strategies to fight epidemics. The mistake that many have made in recent years has been to focus on certain high-profile RNA viruses such as SARS, for example. As a result, no one was interested in viruses that were not being noticed. The researchers therefore recommended that surveillance of human infections caused by respiratory RNA viruses be made a high priority. Finally, the report called for increased priority for research on vaccines against respiratory RNA viruses, including a universal influenza vaccine.
Were these alerts by the scientists too late or did they go unheeded? The coronavirus on the front pages of newspapers and media around the world is looking more and more like the picture researchers had painted of the next vector of a global pandemic.
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