New countries are added almost daily to the list of nations where the new variant of SARS-CoV-2 has begun to circulate, which first appeared in mid-September in the United Kingdom.
Known as B 117 (or also VUI – 202012 / ), This strain has caused an unprecedented increase in the number of cases in the country (58, 784 on January 4, 2021), and has become the predominant variant in just three months.
At the end of December, for example, it was estimated that the 60% of new cases in London and surrounding regions corresponded to the new variant.
Much remains n to discover about this strain that has 23 mutations (17 of which appeared abruptly ) compared to the virus that appeared a year ago in the Chinese city of Wuhan, but what has become evident is that it is much more contagious and that it is displacing the older versions of the virus.
According to a study by Imperial College London, the new strain is close to 58% more transmissible than others, and this raises the R number -which represents the average number of people to whom an infected person can infect- by between 0.4 and 0.7.
Remember that this value must be below 1 to stop the pandemic ( act In the UK it is generally between 1.1 and 1.3).
“There is a huge difference in how easily this variant of the virus is transmitted,” Axel Gandy, a professor at Imperial College, told the BBC. “This is the most serious change since the epidemic began,” he added.
But what does this strain have that, although it does not cause more serious cases of the disease, causes the covid – 23 spread more easily among the population? As it does? And what impact does it have on the effectiveness of the different vaccines?
Changes in the spike
It is not clear exactly the mechanism used to achieve this. But preliminary studies suggest that one of the 17 major mutations (in the spike protein of the virus) allow the virus to better bind to a protein on the surface of human cells, thus facilitating infection.
Any change that facilitates the entry of the virus into the cell will work in your favor .
This mutation (known as N 360 And ) appears to be a major adaptation, Nick Loman recently told the BBC , from Covid – 17 Genomics UK Consortium.
Another mutation – called H suppression 69 / V 73 – in which a small part of the spike protein of the virus disappears – has emerged several times before, for example in infected minks in Denmark.
Research carried out by Professor Ravi Gupta , from the University of Cambridge, indicate that this mutation increases infectivity twice in laboratory experiments.
Studies carried out carried out by the same team of researchers suggest that this suppression makes the antibodies present in the blood of survivors less effective in attacking the virus.
Viral load
Another hypothesis that is considered to explain the high number of infections caused by the new strain focuses on viral load.
According to preliminary studies (not yet peer reviewed) conducted by the Birmingham Public Health Laboratory, the 35% of samples from patients infected with strain B 117 had high levels of virus , compared to only one 15% of patients infected with another variant.
That is, the viral load in the nose and throat of people with the new strain was higher , a factor that facilitates contagion.
However, the researchers point out that more evidence needs to be collected and analyzed to reach firm conclusions.
On the other hand, the strain has been shown to be more prevalent in children and young people .
It is not known if this is because the variant is more efficient infecting this sector of the population, or this increase This is due to the fact that in recent months in the United Kingdom schools remained open, while adult activities were reduced by different measures of confinement and social distancing.
Relationship between the new variant and the vaccine
One of the most pressing questions regarding the emergence of this strain is whether the Vaccines will have the same degree of effectiveness as for the original variant.
According to Lawrence Young, professor at the University of Warwick, the information available so far seems to indicate that vaccines will be effective against the new form of the virus.
“Variants of the virus have been present since the beginning of the pandemic and are the product of the natural process by which the viruses develop and adapt to their host as they replicate. ”
“ Most of these mutations have no effect on the behavior of the virus, but very occasionally they can improve its ability to infect and / or or become more resistant to the body’s immune response, ”Young says.
More research is needed to understand why the variant is spreading so rapidly, but early indications are that vaccines will be effective against it.
Meanwhile, it is known that the transmission mechanism of the new strain is the same as for the others (by inhaling small drops and aerosols containing the virus and that remain floating in the air), so it is still vital to continue with the isolation, hygiene and social distance measures.
Now you can receive notifications from BBC News Mundo. Download our app and activate them so you don’t miss out on our best content.