Novel Coronavirus Mutation, Will Vaccine Still Work?

More than a year after the pandemic began to sweep the globe, as people cheered the arrival of a vaccine, new, more highly transmissible strains of the new crown mutated strain began to emerge, causing new outbreaks in many countries.
At present, the mutant novel coronavirus reported by Britain has been discovered in 60 countries and regions around the world, and the mutant novel coronavirus reported by South Africa has been discovered in 23 countries and regions.
According to NextStrain, a real-time virus mutation tracking platform, as of January 2021, a total of 3,931 novel coronavirus genotypes have been mutated globally.
According to foreign media reported on February 2, local time, the mutation of the new crown strain has been widely circulated in the UK, is still developing new mutations.
Why do viruses mutate?
Why is novel coronavirus mutating at such a crazy rate?
How will the mutation affect epidemic prevention and control and vaccine effectiveness?
Let’s draw a picture to illustrate the answers to these questions.
Article | | Amy diagram GH edit | Paella
Love mutated viruses
For the virus itself, mutations can be beneficial, neutral, or harmful.
The same is true for humans.
Mutation is the “nature” of the virus.
Viruses do not have independent living systems like bacteria, and can only survive by invading and parasitizing living cells.
Viral genes make mistakes as they replicate in large numbers inside cells.
When an error occurs, a mutation occurs.
The RNA virus that Novel coronavirus belongs to is more likely to mutate than the common DNA virus.
Why is that?
First of all, the genetic material of novel coronavirus is positive single-stranded RNA with 29,903 bases. When RNA viruses replicate, they need to use an enzyme (RDRP) to transcribe their genomes. The reason why RNA viruses are prone to mutation is precisely that this enzyme has a low error-correcting ability, and the mismatch rate of nucleotide will become high during genome replication.
This allows RNA viruses to mutate faster than DNA viruses and up to a million times faster than human cells.
Viruses mutate all the time.
In many cases, a mutation is simply a copying error on a single base.
Early in the outbreak, scientists discovered tiny mutations in novel coronavirus.
Sequencing of a virus sample from a Covid-19 patient collected on 8 January 2020 revealed a mutation in the 186th base of viral RNA, from C to U.
Sequencing of virus samples collected seven weeks later from a Guangzhou patient revealed mutations in two more bases.
The strain causing the new pandemic (SARS-CoV-2) accumulated mutations at a steady rate of one to two per month on average, but most of the mutations had no substantial consequences.
That’s because there are two different types of mutations.
Silent mutations do not change the proteins encoded by the genetic material.
Because the amino acids that make up proteins are encoded by three bases, many times a mutation in the third base letter can still encode the same amino acid, so it does not affect the virus’s mechanism of action.
The key is the remaining “non-silent mutation” possibilities.
In February 2020, scientists identified the mutant D614G virus that was then circulating in Europe and the Americas.
Why is it called D614G?
That’s because in the early days of the epidemic, the leading global strain of novel coronavirus was known as “strain D.”
However, the virus soon mutated — the 614 amino acid on the spike protein changed from aspartic acid (D) to glycine (G).
The D and G amino acids have very different properties, so the D614G mutation is not “silent.”
Studies have found that D614G mutation has higher transmission ability and faster replication rate, which obviously affects human survival.
Viral strains carrying the D614G mutation were far from becoming the global mainstream before March 2020, accounting for less than 10% of published strains globally, but had exceeded 90% by the end of June 2020.
What makes the D614G strain so infectious is that the mutation occurred in the spikelin region of the novel coronavirus, the bulges on the surface of the novel coronavirus that can bind to the ACE2 receptor on human cells, enter the cell, and infect it.
More worrying developments continue.
A month ago, the British government reported that a new crown variant strain, known as B.1.1.7, was widespread in the country.
Subsequently, a new mutant strain, named B.1.351, was also reported in South Africa.
At present, “B.1.1.7” and “B.1.351” have rapidly spread to at least 60 countries.
Notably, in each of the variants, the scientists found a mutation in a protein called “N501Y.”
The mutation makes the virus more likely to bind to human cells, making it more infectious.
The “B.1.1.7” variant is estimated to be about 70 percent more infectious than the other variants.
British Prime Minister Boris Johnson said January 22 that a new study showed the mutated strain had increased its lethality by 30 percent.
Is the vaccine still effective against the mutant strain?
Since December 2020, health care workers in the Brazilian city of Manaus have seen a gradual increase in the number of cases of CoviD-19 and the number of deaths.
The sheer number of cases has overwhelmed almost all local medical institutions.
That surprised many scientists because three-quarters of the city had already been infected with the novel coronavirus, enough to achieve herd immunity without causing a massive outbreak.
In fact, after analyzing 31 virus samples taken in mid-December, scientists found that 13 of them were new, mutated strains.
Because novel coronavirus can be re-infected, areas that have theoretically received herd immunity are at risk of renewed outbreaks…
That raises concerns about whether existing new crown vaccines will still be effective against the mutated strains.
In clinical trials in South Africa, where most subjects were infected with a variant of Novel Coronavirus, the overall effectiveness of the vaccine was significantly reduced, according to clinical data recently published by Johnson & Johnson and Novavax.
According to J&J, its vaccine was 72 percent effective in the United States, but only 57 percent effective in South Africa.
According to Novavax, the overall effectiveness of two doses of the vaccine was close to 90 percent in a British trial of 15,000 people, but dropped sharply to less than 50 percent in a South African trial of 4,400 people.
Fauci, an infectious disease expert in the United States, said that to restrain the mutation of the virus, the most fundamental is to prevent the virus from replicating in the human body, which means that the best way to fight the mutation of the virus is to speed up vaccination, race with the virus, to prevent the virus from infecting more people as much as possible.

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