How the virus moved and what it means

Coronavirus | Photo credit: iStock Images

Key landmarks

  • SARS-CoV-2 has about two single-letter mutations in a month in its genome, which is slower than both influenza and HIV.
  • This relative stability of the virus means that two SARS-CoV-2 viruses taken from anywhere in the world differ by only 10 letters RNA, with an average
  • Despite this, at least 12,000 mutations in the SARS-CoV-2 genome have already been cataloged this year.

The British Secretary of Health, Matt Hancock, said that a new strain of coronavirus that appeared in the last two months during genomic surveillance in England includes a number of different mutations.

The strain was detected in parts of the south-east of England, where the virus spread the fastest, he said.

A more complete picture of whether the new strain leads to differences in symptoms or the severity of the disease will appear only after scientists obtain additional data. Researchers in the UK are closely monitoring his movement in the country.

How the coronavirus changes

A mutation, in most cases, is a one-letter change between viruses from two or more people.

Weeks after SARS-CoV-2 was detected in Wuhan, China, scientists looked at the analysis of viral samples and posted the genetic codes online.

In the case of pathogens such as HIV, influenza and SARS-CoV-2, viruses encode their genome into RNA and usually take over mutations quickly because they are copied to their hosts. This is because RNA copying enzymes are prone to errors.

Research has shown that coronaviruses change more slowly than other RNA-based viruses due to an enzyme that fixes copy errors.

SARS-CoV-2 shows about two single-letter mutations in a month in its genome, which is slower than both the flu and HIV.

This relative stability of the virus means that two SARS-CoV-2 viruses taken from anywhere in the world differ by only 10 letters RNA, on average.

Despite this, at least 12,000 mutations in the SARS-CoV-2 genome have already been cataloged this year.

It is important to note that most of these mutations have no impact on the ability of the virus to spread the disease because it does not change the shape of the protein. And mutations that change the shape of the protein could end up harming the virus instead of making it more efficient.

Mutations – and vaccines

To date, there is no evidence to suggest that the new strain of the virus in England is causing more severe symptoms or will make vaccines unnecessary.

However, scientists are following him closely. If the number of mutations is visibly large, then the new variant will be of greater interest.

From now on, all we know is that there is a variant, but it will take many laboratory tests to understand what this biological variant is capable of doing so that it has any impact on the vaccination process that has begun in the UK.

The top three vaccines we have so far – Oxford-AstraZeneca, Pfizer-BioNTech and Moderna – work by training the body’s immune system to target the spike protein.

The Oxford vaccine introduces the spike protein gene through an adenovirus vector, while the other two directly deliver the spike protein gene as an mRNA wrapped inside a nanoparticle. Once the cells in our body produce the spike protein, the immune response begins to recognize it as foreign and produces antibodies and T cells that attack it.

But even if the peak protein moves, the body is trained to attack different parts of the peak after vaccination.

However, if mass vaccination leads to a significant mutation of the virus – to continue to do what it likes best, ie it infects the maximum number of people – then COVID-19 vaccines will have to evolve accordingly and become seasonal vaccines. , as is the case with common influenza vaccines.

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