Health

The super infectious nCoV strain is difficult to resist vaccines


The new strain of nCoV in the UK could become popular, scientists say, but it will take years to become resistant to existing vaccines.

Once the vaccine was approved, opening the door of hope to escape the pandemic, British officials warned urgently about the new more contagious nCoV strain than before.

As the virus quickly swept through London and surrounding areas, Prime Minister Boris Johnson was forced to impose the country’s strictest restriction order since March.

“When the virus changes the way we attack, we also have to adjust our defense method,” he said.

London train stations were packed with people trying to leave the city before the ban went into effect. On December 20, many European countries began to close borders on people from the UK to prevent the new virus from entering.

In South Africa, a similar mutation has occurred. Viruses have been found in 90% of samples on the continent since mid-November.

Variants are used to refer to strains of the virus that have some variation in their “genetic sequence” from the original discovered in Wuhan, China, in December 2019. The variation in the “genetic sequence” of the virus is a natural phenomenon because during the infection and reproduction, they copy their own genome and make mistakes. Up to now, the number of nCoV variants detected by genetic sequencing from random patients is up to several thousand, however the actual number may be higher.

The fact that some strains have become popular just by accident does not mean that the changes made the virus more preeminent. But when the vaccine is available and many human populations appear immune, the pathogen is harder to survive. Scientists believe that the virus will have mutations that make them easily or favorably evade the immune system.

“This is the risk that we need to be aware of,” said Jesse Bloom, an evolutionary biologist at the Fred Hutchinson Cancer Research Center in Seattle. Scientifically, we need to track and determine which trait is influential.

The nCoV strain in the UK has about 20 mutations. Among them, some mutations changed the way of exposure and infection of human cells. Muge Cevik, infectious disease specialist at St. Petersburg University. Andrews in Scotland, scientific advisor to the UK government, says mutants can be replicated and transmitted more efficiently. Officials say its infection rate could be as high as 70%. But this analysis is based solely on an epidemiological model that has not been validated in laboratories, added Dr. Cevik.

Londoners wear masks, walking on the empty streets on the first day the city imposes a third-degree restriction. NY Times

“On top of that, I think we need more test data. We can’t rule out the possibility that high levels of infection depend on human behavior,” she said.

Scientists in South Africa believe that the activity of the new people is the cause of the pandemic, not the new strain.

The new UK report also raises concerns that nCoV could evolve to levels of resistance to recently released vaccines. They surmised some changes in the genetic code of the virus that protects it against certain antibodies.

But experts say it takes years, rather than months, for the virus to become resistant to the vaccine.

“Don’t worry about some supernatural mutation that makes all your antibodies and immune systems useless,” says Dr. Bloom.

“It’s going to be a long process, going on over the years, requiring many mutations. It’s not like an on-off switch,” he added.

The new strain of the virus is of concern only when people who have already been infected or who have been vaccinated re-infect even though antibodies still exist in the body.

But scientific analysis is of little importance to Britain’s neighbors. Concerned about travelers carrying a new variant of entry, the Netherlands said it would suspend flights departing in the UK from December 20 to January 1.

Italy also closed routes and Belgium issued a 24-hour ban on people arriving from the UK by air and train. Germany is making a similar move.

In the UK, officials have announced that they will increase the number of police at centers such as train stations to ensure residents only make essential trips. Health Minister Matt Hancock, on 20/12 said, those who fled London “very irresponsible”. He also thinks the new restrictions could last for months.

Similar to other types of pathogens, nCoV can change shape. Genetic mutations are mostly insignificant, but some may benefit the virus.

Scientists are concerned about the latter possibility. Especially when mass inoculation can prompt the nCoV to adapt. Mutations can then help the virus evade or counteract an immune response.

nCoV is infecting a cell in the human body.  Photo: NY Times

nCoV is infecting a cell in the human body. Image: NY Times

Mutations also have the ability to affect the susceptibility of the virus to antibodies. In some cases, the virus self-removes parts of the genetic code in order to adapt. This phenomenon has appeared at least three times: in Danish weasels, the British people and an immunosuppressed patient, become less responsive to plasma therapy.

“The pathogen is continually transmitting, developing and adapting to the environment,” said Ravindra Gupta, a virus specialist at Cambridge University.

Initially, scientists thought nCoV was quite stable and could not escape the immune response produced by the vaccine, said Dr. Deepti Gurdasani, a clinical epidemiologist at Queen Mary University, London.

“But over the past few months, it is clear that the mutation is still occurring. As natural selection increases with mass vaccination, I think this mutation could become more common,” she said.

The good news is that the technology used in the Pfizer-BioNTech and Moderna vaccines is much easier to adjust and update than the conventional injection. New vaccines also induce a large immune response, so nCoV may need mutations for years before a vaccine modification is needed, says Dr. Trevor Bedford, evolutionary biologist at the Fred Center for Cancer Research. Hutchinson, says.

Thuc Linh (According to the NY Times, BMJ)

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