Health

Controversy, the more evolved nCoV, the less dangerous it is


Some experts think that later variants of nCoV are less dangerous, but others oppose that idea, saying Covid-19 is still a public threat.

Recently, many scientists have discussed two common views: “The next generation nCoV strains will be milder” and “Covid-19 will become a seasonal pathogen”.

This idea is based on many years of medical experience with influenza. The two viruses that caused the 1918 Spanish flu pandemic and 2009 swine flu were both less deadly over time. Many people see Omicron as a sign that the pandemic is over.

“The new strain that first appeared in South Africa is contagious. But there’s also data that shows it causes less severe symptoms, doesn’t damage the lungs. I think this could be a signal that a flare-up is coming. The end of the nightmare is also a sign that the virus is beginning to recede,” Boris Nikoforov, an expert on infectious diseases at the Russian Federal Health Service, told Govorit Moscow radio.

According to Nikiforov, Omicron can make Covid-19 a common seasonal respiratory infection pathogen. In fact, many previous experts have also supported this view.

Monica Gandhi, an infectious disease doctor and professor of medicine at the University of California – San Francisco, USA, said that viruses often evolve to be more contagious, not more deadly. “They want to have many copies of the virus, not kill the host easily, because that’s not a very wise strategy,” Gandhi said.

However, some other scientists disagree with this argument. They show that before it really waned, the 1918 flu virus became more deadly than ever. Other viruses, such as Ebola, become more severe over time.

“The idea that viruses or pathogens will cause milder disease over time is false. If a virus can spread and cause more disease, it will continue to grow and attack people,” the teacher said. Professor David Robertson, Head of the Department of Genomics and Bioinformatics at the University of Glasgow, said.

Medical staff take samples to test for Covid-19 in Bangkok city, Thailand, January 5. Photo: Reuters

In fact, nCoV is not deadly at the time when it multiplies, is most infectious. People usually die two to three weeks after the onset of symptoms. As such, the virus will keep the F0s from dying too soon enough to infect more people.

Omicron appears to be less severe than Alpha or Delta, but both are more dangerous than the original Wuhan version. Besides, viruses do not evolve one way. Omicron did not evolve from Delta, nor did Delta evolve from Alpha. Mutations appear randomly and are harder to predict than that.

Professor Robertson said: “The interesting strains are not linked. If that pattern continues, another variant that emerges in the next six months could be even worse. It is important not to assume that Omicron is the end of the evolution of nCoV.”

Many experts believe that Omicron’s transmission capacity has reached a ceiling. Thus, the variant that appears in the future will find it difficult to compete with it. But just a few months ago, many people had similar reviews about Delta.

“When Omicron infects too many people, it loses its original advantage. This is an opportunity for the virus to create versions that evade the immune system,” Professor Robertson said.

Many experts are also cautious with the idea that Covid-19 will become an endemic, seasonal pathogen, the infection rate is predictable and not out of control.

Stephen Griffin, an associate professor of virology at the University of Leeds, said: “Smallpox, polio, Lassa fever, malaria are endemic. Measles and mumps are endemic, but their severity depends on them. into the vaccination program. Endemic pathogens are not less dangerous.”

As more people gain immunity from vaccines or natural infections, the virus causes fewer severe cases. But then it can rise again. The most effective way to deal with it is to get vaccinated. According to experts, the fewer people infected, the less chance of Covid-19 to develop. But the world hasn’t reached that stage yet.

“The idea that we’re going to reach a pandemic stage into a seasonal epidemic seems counterintuitive. We’ve just had a week with an exponential increase in F0,” Griffin said.

Living with Covid-19 takes more than a national vaccination campaign. It requires a global effort to monitor mutations, helping countries tackle outbreaks as they emerge.

Thuc Linh (Follow Guardian)

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