In Great Britain in the last week an increase in cases is reported due to a new variant present in the country, the variant identified with the initials B.1.617 and the name of Indian, as it was sequenced and reported for the first time in India.
Greater increase in the week
There are 77 cases of the Indian variant in the UK (in one week), but they are the greatest increase compared to the other variants. We see this in the table (heat map HERE below) compiled by Professor Duncan Robertson, Professor of Policy and Strategy Analysis at Loughborough University (England), based on data published Thursday by the National Health Service (Public Health England).
(source Professor Duncan Robertson- @Dr_D_Robertson)
In the map, divided into weeks on the abscissa axis, colors highlight the cases sequenced of a variant (with the relative number) from lightest to darkest as they increase. The variants are listed in the ordinate axis on the left. The table excludes B.1.1.7, the English variant now predominant in the country. The cases of the Indian variant are the most numerous (although some may have been previously detected and reported only now), obviously always relative to the percentage of sequenced positive tests, which in the United Kingdom is a little above (on average) 10 for percent of all positives detected.
Also found in Italy
Variant B.1.617 was first reported in India, but has since been found elsewhere as well. including California. In the international portal PANGO lineages, it is highlighted that 42% of the B.1.617 sequences deposited come from India, 18% from Great Britain, 9% from the USA, but there are cases also in Germany (6% of the sequences filed), Switzerland (5%), but there is also Italy, which reported 5 sequences (against 282 in India).
Two mutations of particular note
The properties of the Indian variant are not yet known in detail, but they can be predicted some features looking at the particular mutations it predicts in the genome. All the 15 changes of amino acids of B.1.617 differ from those of all other variants, when compared to the globally dominant D614G strain designated as B.1, with two notable exceptions.
The exceptions are found in one region of the spike protein: the first a mutation called L452R equal to the change found in the Californian variant (B.1.427). Laboratory experiments show that this change increases transmissibility and decreases the recognition of antibodies (including those present in the plasma of the cured and some neutralizing monoclonal antibodies).
The second mutation of interest occurs in amino acid 484. Many of the variants of concern, such as South African, Brazilian and a peculiar Kent variant, have a mutation called 484K, which is believed to help the virus at least partially evade the body’s immune responses. and those of some vaccines. Indian variant B.1.617 also changed to position 484. However, the 484 mutation differs. The glutamic acid replaced by the polar amino acid not loaded with glutamine arriving at the acronym E484Q. Laboratory experiments confirm that this change also confers an increase in the spike binding properties with the human ACE2 receptor and immune evasion.
The importance of sequencing
While more research is needed to explore the role of these mutations and the impact they may have, the combination of the two aforementioned mutations, sometimes called double mutant, would help explain the increased transmission of the Indian variant in its country of origin: India is experiencing a devastating wave of coronavirus, although it is unclear how much variant B.1.617 is helping to fuel the surge in cases. In fact, a fundamental parameter in these cases is precisely that of sequencing capabilities of the various states where the variants are widespread. Many of them are known because they have been mapped and described in Great Britain, which is one of the most sequenced countries.
The (opposite) role of countries like the UK and Brazil
The future of the virus, crushed by vaccines and the immunity of millions of recovered, it is decided in recent months. Variants can develop more in countries, such as Israel and Great Britain, where the normal or ancestral virus (wild) can no longer find people to infect and therefore must change, or in countries (such as Brazil) where it spreads without containment and therefore can mutate rapidly, since the virus can mutate every time it replicates. It is therefore important, especially in this phase of the pandemic, monitor the emergence and spread of new variants and equip vaccines to deal with them.
The third dose winning hypothesis
Although for now, vaccines seem effective on almost all variants of major concern (variants of concern), with slight drops in effectiveness especially with regard to the South African, the idea of thinking of one third dose that fights the variants the predominant one. The pharmaceutical companies are already working on it and, especially with regard to RNA technology vaccines, it does not seem difficult or too long to update the drug with some changes to this: for example, Moderna announced on April 13 excellent efficacy results in the Phase II study it is carrying out for a vaccine modified to work with the South African variant, but other companies are also in an advanced clinical phase on this hypothesis that could transform the fight against coronavirus in a very similar to the seasonal fight against flu, with a virus that mutates little and a vaccine that is updated every year.
April 16, 2021 (change April 16, 2021 | 12:37)
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