Is the Covid pandemic over soon?
“We are not there yet,” warned the World Health Organization (WHO) in early December. While at least 90% of the world’s population has some form of immunity, “gaps in surveillance, testing, sequencing and vaccination continue to create the ideal conditions for the emergence of a concerning new variant that might cause significant mortality “, warned its general manager Tedros Adhanom Ghebreyesus.
The WHO declares the end of a pandemic. “It’s always an extremely important moment, often subject to controversy”, points out Philippe Sansonetti, microbiologist at the Pasteur Institute, judging that the organization was probably not willing to “whistle the end” of the pandemic. Rather, what experts anticipate is a gradual transformation of the pandemic into an endemic virus, continuing to circulate and causing regular resurgences of the disease. This is the case today with measles or the seasonal flu.
Can we eradicate this disease one day?
It is very unlikely. The SARS epidemic (severe acute respiratory syndrome) which broke out worldwide in 2003 and caused almost 800 deaths, was able to be stemmed by isolation and quarantine measures. A virus, smallpox, was already declared “eradicated” in 1980 thanks to a WHO vaccination campaign.
But this scenario remains extremely rare. “To eradicate a virus, it is necessary that the disease is clinically visible, that there is no animal reservoir, and to have a very effective vaccine, which protects for life. Covid-19 ticks all the wrong boxes,” emphasizes Philippe Sansonetti. Some of the carriers of Covid-19 are indeed asymptomatic, which affects isolation measures. And, unlike smallpox, the virus is transmitted to animals and might continue to circulate among them and reinfect humans. Finally, vaccines provide good protection once morest severe forms of the disease but little once morest reinfections, and booster doses are still necessary.
Even if it suits us all to believe that, we have no reason to think that he will become more likeable.
What are the main risks ahead?
For Étienne Simon-Lorière, Director of the Evolutionary Genomics Unit for RNA Viruses at the Institut Pasteur, “today we allow the virus to circulate far too much”: each time it infects a person, mutations can appear. and are likely to cause it to evolve into more or less severe forms. “Even if it suits us all to believe that, we have no reason to think that he will become more sympathetic”.
In addition, other respiratory viruses might emerge: since the appearance of Sras, Mers, and Sars-Cov2, “we have found a good dozen coronaviruses in bats which might potentially infect humans”, notes Arnaud Fontanet, specialist in emerging diseases at the Institut Pasteur.
About 60%/70% of emerging diseases are of zoonotic origin, ie they are naturally transmitted from vertebrate animals to humans and vice versa. By occupying larger and larger areas of the globe, by travelling, by intensifying their interactions with animals, humans contribute to disrupting the ecosystem and favoring the transmission of viruses.
How to prepare for it?
For Arnaud Fontanet, “much can and must be done at the start of an epidemic”. Thus, in 2020, Denmark decided on confinement very early, which allowed it to get out of it more quickly. Another imperative: “to have the capacity to develop very early tests”, at the start of an epidemic, so as to isolate patients very quickly. “Unfortunately, today we are still in the reaction, not in the anticipation”, regrets the researcher.
