- Lidia Sanchez
- Animal policy
49 minutes ago
With the confirmation in several countries of the registration of the SARS-CoV-2 variant which wreaked havoc in the UK, confusion has also arisen over the terms used to refer to it.
Is it correct to say that this is a new strain? Is a mutation the same as a variant? What is a lineage?
Before detailing what each term refers to, let’s first remember that, as the experts explained to us, all viruses constantly mutate, at different rates and with different repercussions.
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Regarding variant B.1.1.7, reported by the UK in December, there are concerns that it may be up to 50% more contagious.
However, there is no scientific evidence yet that it causes more damage to patients with COVID-19 or makes the virus more deadly. It also does not affect the effectiveness of vaccines developed so far.
Mutations create variants or lineages
When infections occur, copying “errors” occur, and then mutations or changes in the virus’s genetic code occur, such as the one that causes COVID-19.
By sequencing or genetically analyzing the virus from samples taken from different parts of the world, scientists are identifying certain characteristics that allow these mutations to be grouped into variants or lineages.
For analysis, phylogenetic trees are created, which are like family trees in which all parents are expressed that are released from viruses such as SARS-CoV-2.
Each of the branches that arise directly from SARS-CoV-2 are called lineages, which are designated by a series of numbers and a letter of the alphabet, to identify them, given their order of appearance and genetic makeup.
Line B.1.1.7 has different mutations in its genome, so far around 23, but the main one that grows at position 501 of its genetic code, where the amino acid asparagine (N) has been replaced. by tyrosine (Y).
The abbreviation for this mutation is N501Y, which is also sometimes called S: N501Y, to clarify that it is found in the peak protein of the virus.
It is therefore correct to say that the B.1.1.7 variant or line has arrived in Mexico.
In addition to the UK variant, scientists have identified the 501Y.V2 variant in South Africa.
We don’t want to confuse you, but one detail is that the British and South African variants both share one mutation, that of position 501.
In the United States, 72 cases of variant B.1.1.7. have been confirmed so far, according to the Centers for Disease Control and Prevention (CDC).
So what is a strain?
To understand this, we can immediately mention that SARS-CoV-2 is one of the different strains of the coronavirus.
The two most well-known types or strains of coronavirus to date are: SARS-CoV-2 found in Wuhan, China, since late 2019.
And before that SARS-CoV, which causes severe acute respiratory syndrome or SARS. So: each of the new types or species of coronavirus is called a strain.
It is imprecise to say that the UK registered variant is new, or to mention that a new strain has arrived.
To do this, the virus would have to undergo a drastic change or mutation in its genetic chain, which has not happened so far.
This is why, for now, the vaccines developed so far are still considered useful in combating the virus and preventing further cases of death from Covid.
“There is a strain of coronavirus. It is Sars-Cov-2. It is the only strain and there are variants of this strain. These are variants,” explained Professor Tom Connor of the School of Biosciences from Cardiff University to The Independent in December on B.1.1.7.