A variant in the south-east of the country, then the south-west, then in the north of England ... Since the discovery in the United Kingdom, in December, of a variant of the new coronavirus considered to be more contagious, the surveillance of the epidemic is clearly increased.
So much so that new variants, identified in several regions of the country, have appeared, according to British media.
Detections which can be explained by the numerous sequencing carried out in the country, but also the strong circulation of the virus at the local level.
In each territory, there are actually "thousands of variants that are detected frequently," summarizes Simon Clarke, associate professor of cellular microbiology at the University of Reading.
“They're only noticed when they're likely to cause a problem,” he adds.
The United Kingdom, has, at this stage, detected three variants deemed "worrying" and initially seen on its own territory, according to government data.
First of all there is the one that we called, from the month of December, the “English variant”, B.1.1.7 (or VOC202012 / 01), also nicknamed “Kent variant”, because it was initially detected in the south-east of the UK.
It has spread throughout the country, but also abroad, including in France.
More recently, two other variants have been found in Bristol (VOC-202102/02), in the south-west of England, and in Liverpool (VUI-202102/01), in the north of England.
These last two variants, one similar to that of Kent, and the other similar to the coronavirus originally identified in Wuhan, have the specificity of presenting the same mutation as the so-called "South African" variant, called E484K, which decreases the effectiveness of antibodies.
These variants were born in "specific populations in the United Kingdom, but the country only sequences 5 to 10% of its samples, so these variants could also circulate elsewhere in the country", specifies the virologist Julian Tang, honorary professor at the 'University of Leicester.
More sequencing
The South African and Brazilian variants, also under scrutiny because of their mutations or their contagiousness, also circulate in the kingdom, recalls Julian Tang.
“All these variants are worrying, sometimes because they seem more transmissible (B.1.1.7.), But also because they present the E484K mutation (all except the Kent variant), which seems to limit the effectiveness of the vaccine against these viruses ”, develops the specialist.
"We have also spotted a variant nicknamed" Nigerian "because it is linked to trips from Nigeria, but we do not yet know if it is problematic", adds, for his part, Simon Clarke.
Why are we seeing such a variety of worrying new coronaviruses on British soil?
Already, because the United Kingdom has "the best infrastructure to sequence and follow the genetic codes of viruses that are isolated", explains Simon Clarke.
“The UK is currently doing more sequencing than any other country in the world, so we are seeing these variants faster than in other countries,” confirms Julian Tang.
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According to the virologist, the scale of the epidemic across the Channel, which has already killed more than 115,000, can also explain this variety.
“The UK has had a lot of population replications of the virus - leading to more cases and more deaths than any other European country.
If you allow a virus to replicate freely, it will generate more host-adapted mutations, which allows it to infect more easily and spread more easily to new hosts, ”he explains.
Variants all over the world
These reports are not entirely a surprise.
In fact, “there are new variants appearing everywhere, in France, in China, in Brazil… The question is: are they causing problems?
Out of the thousands, only a small number are suspected of causing problems, ”says Simon Clarke.
This suggests that the question of variants is a problem in the long term.
“As more countries increase their sequencing capacity, we will see more and more variants detected around the world.
We also do this every year with the flu virus.
This is how the seasonal composition of the flu vaccine is designed for the northern and southern hemispheres each year, ”adds Julian Tang.
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To better fight against the epidemic, it is therefore sufficient to adapt your vaccines.
But at this point, the ongoing vaccination campaign in the UK, which has more than 15 million vaccinated among the most vulnerable people and caregivers, is not changing, and rightly so.
"We must vaccinate as many people as possible using existing vaccines, since there are many people who fall ill with Covid-19 from viruses that are not derived from variants," recalls Julian Tang.
Many manufacturers of Covid-19 vaccines have also announced that they will be able to quickly change their formulas according to the new variants.
However, vaccine matching does not work with every trial.
“The design of vaccines is based on a forecast that tells which variant circulates the most in the world, and which ones will be problematic in the winter.
Sometimes these predictions are wrong.
Other times, the vaccine may not have an effect on the immune system, for some reason, ”says Simon Clarke.
And there, the problem is greater: "We do not yet know how to push an immune system that does not want to react to a vaccine", adds the microbiologist, specifying that this problem remains however occasional: "Some years, everything is fine, and sometimes there is a year or it goes wrong.
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In the long term, there is still a chance that these variant appearances could be beneficial, according to Julian Tang, who also refers to the experience we have with seasonal flu.
"Without control of viral replication, (as with the flu, where only the most vulnerable are vaccinated), this adaptation of the virus will continue, but can eventually lead to a milder version of the virus, like the common cold coronaviruses than the 'we see each year, with less severe diseases, few hospitalizations, and practically few deaths,' said the virologist.
Despite these uncertainties, the example of the United Kingdom confirms a fact: we will have to learn to live, not only with the coronavirus, but also with its variants.