a disease that will probably never be eradicated and a taste of the future

Is the Covid pandemic over soon?

“We are not there yet,” the World Health Organization (WHO) warned in early December. While at least 90% of the world’s population has some form of immunity, “shortcomings in surveillance, testing, sequencing and vaccination continue to create the perfect conditions for the emergence of a worrying new variant that could cause significant mortality,” its director-general warned . Tedros Adhanom Ghebreyesus.

WHO declares the end of a pandemic. “It is always an extremely important moment, often the subject of controversy”, notes Philippe Sansonetti, microbiologist at the Institut Pasteur, and considers that the organization was probably not ready to “whistle the end” of the pandemic. Rather, what experts expect is a gradual transformation of the pandemic into an endemic virus that continues to circulate and cause regular resurgences of the disease. This is the case today with measles or seasonal influenza.

Can we eradicate this disease one day?

It is very unlikely. The SARS (severe acute respiratory syndrome) epidemic, which broke out worldwide in 2003 and caused nearly 800 deaths, could be ameliorated by isolation and quarantine measures. One virus, smallpox, was already declared “eradicated” in 1980 thanks to a WHO vaccination campaign.

But this scenario remains extremely rare. “In order to eradicate a virus, it is necessary that the disease is clinically visible, that there is no animal reservoir, and that you have a very effective vaccine that protects for life. Covid-19 ticks all the wrong boxes,” emphasizes Philippe Sansonetti. Some of the carriers of Covid-19 are actually asymptomatic, which affects isolation measures. And unlike smallpox, the virus is transmitted to animals and can continue to circulate among them and reinfect humans. Finally, vaccines provide good protection against severe forms of the disease, but little against reinfections, and booster doses are still needed.

Although we all like to think so, we have no reason to believe that he will become any more likable.

What are the main risks ahead?

For √Čtienne Simon-Lori√®re, director of the evolutionary genomics unit for RNA viruses at the Institut Pasteur, “today we allow the virus to circulate far too much”: every time it infects a person, mutations can occur and are likely to cause it to develop into more or less serious forms. “Although it suits us all to believe so, we have no reason to believe that he will become more likable”.

In addition, other respiratory viruses may appear: since the emergence of Sras, Mers and Sars-Cov2, “we have found a good dozen coronaviruses in bats that can potentially infect humans”, notes Arnaud Fontanet, specialist in emerging diseases at the Pasteur Institute.

About 60%/70% of new diseases are of zoonotic origin, i.e. they are naturally transmitted from vertebrates to humans and vice versa. By occupying larger and larger areas of the globe, by traveling, by intensifying their interactions with animals, humans contribute to disrupting the ecosystem and promoting the transmission of viruses.

How to prepare for it?

For Arnaud Fontanet “much can and must be done at the start of an epidemic”. Denmark thus decided in 2020 to be locked up very early, which made it possible to get out of it faster. Another necessity: “to have the capacity to develop very early tests”, at the start of an epidemic, to isolate patients very quickly. “Unfortunately, today we are still in the reaction, not the expectation”, laments the researcher.

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