Why are there different variants of a virus? and how do we stop them? Virus changes help them to survive, the more a virus is circulating in a population and causing infections, the higher is the likelihood of the virus mutating, which means that if the virus spreads, it replicates. According to WHO most viral mutations have little to no impact on the virus’s ability to cause infections and disease. However, depending on the changes are located in the virus, they may affect the virus resources to transmit, spread or produce more severe symptoms.
In this sense, the key to stop the virus to mutate is to work in order to stop its spread. Therefore, current measures to reduce transmission are indispensable to work against new variants by reducing the viral transmission and opportunities for the virus to mutate.
New viruses have always been named after the locations from which they have emerged, this is for example the case of Ebola, which is an African River, and it is also the case of the SARS-CoV-2 variants so far. However, The World Health Organization recently announced the new names of the virus that produces Covid-19 disease, which have been given letters from the Greek alphabet.
One of the reasons of this change lays on the damage that naming the variants after the country’s names can be making on these places, and the stigmatisation of the people from those countries. In words of Maria Van Kerhove, WHO epidemiologist “No country should be stigmatised for detecting and reporting variants”.
Another reason that WHO gave for the change of names was, that scientific names are too hard to remember and pronounce in different languages. As a result of different options that were considered to name the variants South Africa, Brazil and India variants have now been given the letters alpha, beta, gamma, delta according to the order of their recognition. Other variants of interest will continue to be named after the rest of the letters of the alphabet.
The new variant of the SARS-CoV-2 virus that has emerged, called Omicron (lineage B.1 .1.529 ) has a variation of 55 mutations in the virus genome, as far as is known at the moment, with respect to the first virus, of which 32 are variations in the spike protein (S) a protein that is one of the keys in the viral infection process and which therefore plays a fundamental role in the infection of cells, and which could turn it into a variant that transmits more quickly. For all these reasons, the WHO could declare it as a variant with a higher risk of infection, but there is still no information to support this information, for the moment, it is a variant that should be studied and analysed in depth to corroborate its level of transmissibility, because it may not be a cause for greater alarm.
One of the most concerning variants have appeared so far is the Delta variant (also known as B.1.617.2), which originally appeared in India. The Delta variant includes several changes on the spike protein of the virus (T19R, (V70F*), T95I, G142D, E156-, F157-, R158G, (A222V*), (W258L*), (K417N*), L452R, T478K, D614G, P681R, D950N), it has demonstrated to Increased transmissibility of the virus, it has also showed potential reduction in neutralization by some monoclonal antibody treatment and potential reduction in neutralization by post-vaccination sera. Delta variant is the most recently designated variant of concern, as classified by the World Health Organization (WHO).
We talked about different variants of the virus on this article before, however by the time we shared that information, the number of principal variants of the virus was lower: the UK variant (now named as Alpha variant), the Brazilian (Gamma Variant) and the South African variant (Beta Variant) Since then, more genetic variants of SARS-CoV-2 have been emerging and circulating around the world throughout the COVID-19 pandemic.
The B.1.1.7 (Alpha), B.1.351 (Beta), B.1.617.2 (Delta), and P.1 (Gamma), variants are the ones which have been classified as variants of concern by The US Department of Health and Human Services (HHS).
On the other hand, the named kappa variant has also been detected in India, and it is originated from the same strain than Delta Variant, but unlike this one has not been notified to be highly concerning by WHO, they just have listed it as a variant of interest, in order to be observed.
Some of the SARS-CoV-2 variants active at the moment are:
Viruses are changing all the time, some of these variations allow the virus to spread more easily or make it resistant to treatments or vaccines, which help those variants to survive.
Furthermore, if a particular variant is introduced into a new location and initiate a local epidemic, the frequency of contagiousness can rapidly increase, and when a new variant can become common before its identification, which makes them more dangerous.
On the other hand, a virus carrying a particular mutation can rise in frequency by chance if it is carried by a person who transmits the infectious disease to an unusually large number of other people, if it is moved to a new uninfected location, or introduced into a new segment of the population.
The Delta variant has demonstrated to be so far the most dangerous SARS-CoV-2 mutation, given that it is the most transmissible one. The world Health Organization declared that vaccines available are still effective against the previously known as B.1.617.2 (Beta Variant) first discovered in India. However, the Economist estimates that there have been more than 1 million COVID-19 deaths in India this year.
On the other hand, the delta variant has spread rapidly as well and it has showed to be the most extended SARS-CoV-2 variant in countries such as Canada, Indonesia, Pakistan, Portugal an Russia. According to GISAID, which is a data-sharing initiative, the mutation has been identified in at least 70 countries. Furthermore, researchers at the University of Exeter, the NHS Foundation Trust, reported a significant increase in mortality risk due to the B.1.1.7 Variant (Alpha Variant, initially identified in UK) and from there, it has spread rapidly to a large number of countries.
All Covid-19 vaccines have been developed before the mutations appeared and were subsequently identified. Although several studies carried out so far have suggested that vaccines are not that effective for SARS-CoV-2 variants, they still appear to contribute to the protection against the disease, and it helps to build the herd immunity which is the key to overcome this pandemic. However, there is still questions unanswered in this regard. As far as we know we could can get sick from Covid-19 again with new strains.
Furthermore, some of the pharmaceutical vaccine manufacturers have declared to be developing additional vaccines in order to complement the ones we have available at the moment, and also improve the protection against the different variants.
In conclusion, not all vaccines available and licensed so far have the same effectiveness in their response against the different strains, however, vaccines are the key in this fight against the pandemic for Covid-19 and researchers will continue to work in order to adjust the available vaccines to all the new identified variants. (Read more about vaccines).
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