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For the past couple of days, much attention has been paid to B.1.1.7, a variant of the SARS-CoV-2 coronavirus recently identified in the UK and which appears to be able to spread more easily than the variants circulated so far. and that led to the ongoing pandemic. As a precaution, several countries, including Italy, have suspended flights to and from the UK, while researchers are working to understand whether B.1.1.7 is really new to worry about.
Despite quite alarmed statements by British Prime Minister Boris Johnson, to date there is no evidence to support with certainty that this variant could significantly affect the progress of the pandemic. Virologists and experts are still evaluating the situation and many of them are still not convinced that B.1.1.7 is more adept at passing from individual to individual than other known and analyzed variants of the coronavirus.
The discovery
Scientific advisers to the British government realized that something was wrong on December 8, when they noticed that in Kent, in the south-east of England, a particular variant of the coronavirus was emerging, with unique characteristics in the world. its evolution detected in late summer.
In the last two weeks, the variant known as B.1.1.7 has been found to be among the most widespread in various areas of the UK, including London, and has probably now spread to other European countries as well, albeit with a minor incidence (at least according to the data collected so far).
What caught the attention and continues to keep researchers interested is the speed with which 17 different mutations have accumulated, leading to the new variant. It is extremely rare for a virus to accumulate so many mutations in a short time and for these to concur to constitute a significantly different variant from the initial ones. For this reason, researchers are working to study mutations, better understand what they do, and then determine whether the new variant can be defined as riskier than the others.
Mutations and variants
To better understand the history of B.1.1.7 it is necessary to go back a few steps, with a review of the mutations. A virus enters an organism and uses its cells to replicate, that is, to create new copies of itself that will then join other cells to continue the process. It is not a very precise mechanism and can lead to some errors in the phase in which the genetic material of the virus is transcribed to make a copy, a bit like when you re-copy a text and inadvertently write a typographical error. It is in the order of things, it occurs all the time in nature in the processes of replication of genetic material. The result of these typographical errors are mutations, almost always harmless and that are transmitted to subsequent generations, accumulating with the new ones produced by the replication processes.
These inaccuracies determine the progressive increase of the genealogical tree of a virus, with new branches that, however, do not imply the development of a new “viral strain”. Virologists reserve this definition for a new generation of viruses that present marked and significant differences from the previous ones, especially in the results of their activities.
Although not all agree on the limit beyond which we can speak of a new strain, criteria such as: modified capacity of the virus to cause disease (virulence), new resistance to pharmacological treatments that previously managed to keep it under control, increased capacity are taken into account to evade the body’s immune defenses.
B.1.1.7
The current coronavirus has become in a few months one of the most studied viruses in the entire history of mankind. The researchers observed its evolution as it spread through the population and in different parts of the world, detecting an average of 1-2 mutations per month. Compared to the coronavirus identified in China earlier this year, it means that there are versions of the virus in circulation today with about 20 differences. However, it had not yet happened that researchers detected nearly 20 mutations that apparently occurred substantially at once.
The hypothesis is that the mutations have accumulated in an individual who has been living with the coronavirus for a long time, a circumstance that has allowed the virus to evolve rapidly. Several mutations would have manifested, in evolutionary competition with each other, which would eventually lead to the now defined variant B.1.1.7 and which later spread among the population.
In the UK, they realized that this variant was spreading rapidly thanks to molecular tests, those carried out by analyzing saliva and mucus samples collected with a swab that penetrates deep into the nostrils and oral cavity.
The first traces of the variant were found at the end of last September. As of mid-November, B.1.1.7 accounted for around 26 per cent of new positive cases detected in the UK. As of December 9, the incidence was much higher and the variant is now estimated to be prevalent in London, with 60% of new cases attributable to the mutated virus.
During a press conference, Johnson said that the various mutations would increase the ability of the coronavirus to spread between individuals by 70 percent, explaining that he had also decided on a new lockdown for this reason. His statements, however, did not convince the researchers, who believe premature conclusions of this type: B.1.1.7 could have been spread in a more trivial way by chance and this brings us back to a few months ago, when for a few days a variant. It is believed that the Spanish coronavirus can spread more easily.
The “Spanish variant”
Today, researchers believe that in reality the “Spanish variant” (B.1.177, not to be confused with the British one) was no longer transmissible than others: more simply, it spread after the resumption of tourism in Spain during the summer, with several travelers that they would hire it during their vacations and then import it to their respective countries. Something similar may have happened with B.1.1.7, given the high number of population movements in the London metropolitan area.
However, the new variant should not be underestimated and that is why several investigations are being carried out on its characteristics. Among the 17 mutations that it has accumulated, there are 8 that affect the gene that contains the instructions to produce the protein found in the tips of the coronavirus, and that the virus uses to evade the defenses of cell membranes to inject itself into cells. their own genetic material and replicate.
Mutations and severity of disease
A mutation, called N501Y, has been known for some time and is known to enhance the ability of the coronavirus to bind to cell membranes. The 69-70del mutation, on the other hand, contributes to making the coronavirus more elusive of immune defenses, especially in immunosuppressed individuals (therefore with a less efficient immune system). This mutation is believed to be responsible for the reduced efficacy of some therapies to treat severe cases of COVID-19, such as those based on convalescent plasma. However, it is not yet clear if the mutation alone determines this circumstance or if there are others that contribute to the phenomenon.
However, it is still early to argue that B.1.1.7 causes a more severe version of COVID-19, simply because not enough data has yet been collected from current patients or those who had become ill in recent weeks. In the case of the Spanish variant, some estimated that there could be a 50 percent increase in fatality, but subsequent analyzes ruled out this possibility; the estimate was made on the basis of unreliable data or was collected under difficult-to-verify circumstances.
No flights
The interruption of flights to and from the United Kingdom decided by several countries in recent days could help slow the spread of the new variant, but according to the researchers it is likely that by now B.1.1.7 has begun to spread widely in the Foreign. considering it had been around for several weeks in the UK. In the Netherlands, the variant was isolated in at least one individual, and the same happened in Italy with an individual who returned from the UK and is now isolated.
What about vaccines?
In recent days, there have also been reports of the risk of vaccines being licensed or licensed to be less effective with this variant. Also in this case it is too early to make such claims, not to mention that vaccines intervene in different mechanisms so that the immune system learns to recognize and stop the coronavirus, before it does harm. There is no evidence that vaccines do not work against this variant, but we will know more in the coming weeks, also looking at the trend of the pandemic in countries where vaccination has already started, such as the United Kingdom.
In general, however, vaccines are useful not only to protect people, but precisely to help the viruses against which they were developed to circulate less and less. A lower circulation of a virus implies a lower passage from one individual to another and, therefore, a lower possibility that the virus evolves and accumulates new mutations. On the other hand, the presence of the vaccine could push the coronavirus to evolve differently, so it is important to monitor its mutations.
However, the history of B.1.1.7 has shown that the system for monitoring and analyzing the evolutions of the coronavirus has become quite accurate, even if it is still difficult to prevent particular variants from spreading among the population. Being able to identify these developments as soon as possible could be an essential activity in the coming months, hand in hand with vaccination campaigns to stop the pandemic as much as possible.
summarizing
• Mutations in the SARS-CoV-2 coronavirus continually arise, resulting in variants that circulate in the population for months. B.1.1.7 is a particular variant, with a high number of mutations.
• There are indications that B.1.1.7 spreads more easily than other variants, but the data is still preliminary and needs to be investigated.
• To date, there is no reliable evidence to support that B.1.1.7 causes more serious forms of COVID-19.
• The variant appears to make those infected more contagious, but they are not at increased risk of developing severe symptoms.
• We do not yet know if B.1.1.7 makes the vaccines developed and / or licensed so far less effective, but there are elements to be optimistic about maintaining their ability to combat the coronavirus.
• Vaccination is and will continue to be the most important way to reduce the circulation of the coronavirus, but if B.1.1.7 proves to be more transmissible, the use of precautions such as the use of masks and physical distancing will continue to be important.
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