Tuesday , October 26 2021

When will the Covid-19 epidemic end?


We have been dealing with the Covid-19 pandemic for over 20 months. Several times, we thought we saw the end of this terrible epidemic. But every time a new wave has arrived. However, experts assure you: all epidemics are over. But under what conditions and within what timeframe? Who will risk announcing victory over the virus?

« There will be an end to this pandemic », Assured last September 5, Jérôme Salomon, Director General of Health and BFM TV. « France is on the right track to return to normal life ”Jean Castex also advanced on 31 August. ” Epidemics always have an end, recalls Jean-Claude Manuguerra, a specialist in infectious diseases at the Institut Pasteur. A epidemic it can be extinguished by the competition of another virus, due to weather report, or collective immunity ». The end of pandemic, really? Does this mean that the virus will disappear as quickly as it appeared? That we will finally be able to free ourselves from masks and barrier gestures? That the vaccination will eradicate the Covid-19 ?

From pandemic to endemic

To talk about the end of the epidemic, we must first agree what is an epidemic. And the definitions differ greatly depending on the context and the disease. In general, an epidemic is characterized by the rapid growth ofincidence of a disease in a region and for a certain period. “ For Listeria, we are talking about an epidemic from the first case Remember Jean-Claude Manuguerra. For grip, it takes tens of thousands of deaths to talk about an epidemic. And in the case of Page, despite 1.5 million pollutions in 2020, we are no longer talking about a pandemic. The disease has passed into a phase endemic, which is the natural course of all epidemics. Endemicity is defined by the habitual presence of a disease, usually infectious, in a given population or in a specific region, with a stable incidence. ” the malaria, johepatitis A or influenza are therefore considered endemic Says Jean-Claude Manuguerra.

The most famous example of this change is the Spanish flu virus that continued to circulate after the devastating pandemic episode of 1918-1920. “ When this pandemic [de grippe espagnole] gradually fading, the responsible virus, which was later identified as H1N1, became seasonal He told the newspaper The world Professor Patrick Berche in June 2020. This did not prevent some of his “descendants” from leading to new epidemics such as 1957, recalls, for his part, Jean-Claude Manuguerra.

The pandemic period will end in late 2022

In an interview with a newspaper Point last July, the head of Moderna, Stéphane Bancel, estimated that ” the period of pandemic, the rapid evolution of the virus and the almost continuous planetary pollution, will end at the end of 2022 According to him, a “pandemic period” will open in which “nuclei of contaminations », But where the general situation will stabilize. In short, we will have learned coexist with the virus. However, some countries such as China and Australia still cling to the idea of ​​eradicating the virus, generally limiting it to the appearance of the slightest case. A strategy doomed to failure, as evidenced by the increase in cases in these countries. ” We can consider that with an incidence rate of between 10 and 20 cases per 100,000 inhabitants, we will be out of the pandemic phase. For his part, he considers Jean-Claude Manuguerra. A figure reached twice since the beginning of the pandemic, after the first imprecise between May and August 2020 and briefly in July 2021. And, as we have seen, this has failed to stabilize the number of cases, which has started again.

Don’t expect a decrease in virulence

One widespread belief is that the virus loses its virulence as the pandemic progresses so as not to kill its host, which is also its vector of transmission. Unfortunately, this view does not stand up to the analysis of the facts, the HIV having become, for example, more virulent over time. Likewise, the variant Delta seems to cause more severe forms than the Alpha variant. ” In the event that SARS-CoV-2, el symptoms severe ones usually appear after two weeks of infection, but more than 95% of transmissions occur before the 11the day. In other words, from the point of view of this coronavirus, late (particularly inflammatory) pathological manifestations of virulence do not constitute a loss of transmission opportunities. », Samuel Alizon gives faith, Director of Research at the CNRS iWRITE.

Only one disease in history has been eradicated with one vaccine : the smallpox, the last known case of which dates back to 1978 in the United Kingdom. ” This eradication has been possible at the expense of relentless vaccination campaigns for decades. In addition, SARS-CoV-2 has an animal repository, so it is almost impossible to eradicate the virus, as it is the agent pathogens from finished for example », Says Éric Dortenzio, research director at Inserm. In fact, most of the viruses or bacteria responsible for past pandemics are still present today, whether it is the plague, H1N1 or Ebola. Diseases that still experience sporadic epidemic recruits.

Even if the virus were eradicated from the human population, it would continue to circulate in animals and could undergo unexpected mutations.

According to experts, the safest way to end an outbreak is to slow the spread of the disease and counteract its side effects. Pest control and hygiene standards, for example, have been successful in pest control and anger. He triple therapies drastically allowed reduce AIDS mortality. In the event that measles, vaccination reduces the number of contaminations to almost zero, but this requires reaching almost 100% of vaccination coverage and that the immunity conferred by the vaccine is sterilizing, that is, it prevents the transmission of the virus. Two conditions that will certainly never be met with Covid-19. ” Even if the virus were eradicated from the human population, it would continue to circulate in animals and it could undergo unexpected mutations Warns Jean-Claude Manuguerra.

A more political than health decision

In short, the announcement of the “end of the pandemic” and the lifting of barrier gestures will be more of a political decision than a health one. “Mission accomplished,” said U.S. President George W. Bush on the 1stis May 2003 announcing the end of the war in Iraq. He knew, however, that the fight was far from won, as American soldiers had withdrawn from the country only in December 2011. Only Denmark has dared to announce the end of the pandemic, with the lifting of all last restrictions. But without the security they will not return.

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