How does the Covid pandemic end: what will happen after Omicron?

As the weary world faces its third year of coronavirus, just as the most contagious variant to date has exacerbated its spread, many scientists are optimistic that the loss of global health caused by this pandemic will be reduced in 2022.

Although Omicron coronavirus variant There may be a crisis in the next few months, but the most likely scenario shows that the prospects will greatly improve afterwards, because the immunity of the global population through vaccination and natural infections may make the consequences of the virus less serious.

“Omicron cases in Europe and North America are rising very fast, and we may see the same rapid decline in the next one or two months, although it may take four to six months for this variant to become global Make an impact,” said Sir Jeremy Farrar, director of the Wellcome Medical Foundation.

He said that after the Omicron wave has passed, “the established immunity may give us a period of calm, but this can work in many ways.”

An encouraging sign appeared on Thursday, when Omicron first appeared in South Africa in November, lifting restrictions on people’s movement due to the surge in cases. “All indicators indicate that the country may have passed the peak of the fourth wave,” the cabinet statement said.

Tim Colbourn, Professor of Epidemiology at University College London, said, “It is completely reasonable to think that the burden of the new crown virus in 2022 can be reduced by 95% so that it is no longer one of the top ten health problems. A reasonable goal to end the pandemic.”

Some experts regard Omicron itself as a pointer to the future evolution of the Sars-Cov-2 virus, because natural selection facilitates the transmission of mutations as quickly and efficiently as possible between people who already have a certain degree of immune protection.

Laboratory tests have shown that mutations in Omicron make it more contagious than previous mutations in the nasal cavity and upper respiratory tract-conducive to rapid spread-but on the contrary, it is unlikely to penetrate deep into the lungs, where it tends to cause the greatest harm.

These conclusions are supported by epidemiological evidence, namely Reduced risk of serious illness Using Omicron can be reduced by half or more.

According to the model of the University of Washington Institute of Health Indicators and Evaluation, Omicron’s high infectiousness means that the number of people infected worldwide will reach a staggering 3 billion in the next two months, as many as the first two years of the pandemic.

Chris Murray, director of the institute, said: “However, compared to the global delta wave or the peak of last winter, this large-scale surge of infections and cases will translate into a surge in hospitalizations.”

Evidence to date indicates that Omicron will replace Delta as a variant that is popular in most parts of the world, just as Delta wiped out previous strains. “I feel relieved about this prospect,” Farrar said.

“If you have different variants spreading at the same time, I would be more worried, because it means they are using different ecological niches, and we will eventually encounter potentially dangerous dynamics where multiple strains interact.”

People line up in Portugal for the Covid test © Horacio Villalobos/Corbis/Getty Images

Even if Omicron does become the dominant strain, another variant of the virus is certain.

Although individual changes in the genetic code are random events in the process of virus replication-no one foresaw Mutational diversity This is the characteristic of Omicron-the environmental pressures that allow some people to thrive are predictable.

In a world where most people have been exposed to Sars-Cov-2, variants that can spread quickly and easily while evading the attention of the human immune system will be more popular. Mutations that make the virus more deadly are unlikely to make it healthier, and may even be an obstacle if they prevent effective transmission.

“Although you can imagine the emergence of a deadly new variant that is more transmissible, but also more harmful… I don’t know how feasible this is for this virus,” cell biologist and University College London professor Jennifer Ron said. “Sars-Cov-2 relies on infected cells, and it may be close to the limit of its pool.”

Over time, whether new pathogens are established in the population will become milder, this is a question of debate among scientists. But Paul Hunter, a professor of medicine at the University of East Anglia, is convinced that the coronavirus is indeed the case.

Four human coronaviruses have been spreading around the world for a long time, causing mild to moderate cold-like symptoms. When they first spread from animals to humans, they may have caused severe epidemics.

In particular, the recently arrived OC43 was crossed from a cow around 1889 and caused what was called at the time “Russian Flu”Hunter believes that this will lead to an increasingly mild wave of Covid-like diseases in the past four to five years-although not everyone believes the evidence.

“Sars-Cov-2 will always throw out new variants, but our cellular immunity will establish protection against serious diseases every time we are infected,” he said. “Ultimately, we will no longer worry about it.”

If Sars-Cov-2 develops in a substantially linear fashion, then this reassuring situation may apply. However, Farrar points out that the risk of a sudden evolutionary jump to “something outside the left field of the existing lineage” is small.

One possibility is that Sars-Cov-2 evolved in animal populations and then returned to humans. Influenza pandemics usually start with flu viruses spreading from birds or pigs.

Alternatively, Sars-Cov-2 can exchange genes with different viruses through “gene recombination”. For example, if someone is infected with Sars-Cov-2 and the related Mers coronavirus at the same time, this coronavirus is not easy to spread from person to person, but it will kill about 40% of infected people. It is conceivable that there will be a nightmare A general mixture is both infectious and lethal.

Although such an evolutionary leap is not impossible, most experts believe it is extremely unlikely. Colborn said: “Compared to some variants of SARS Coronavirus 2, I am more afraid of another pandemic caused by a new virus that we don’t know yet.”

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