Epsilon variant: this is what it is and why it is capable of bypassing vaccines – Chronicle

Epsilon variant: this is what it is and why it is capable of bypassing vaccines – Chronicle
Epsilon variant: this is what it is and why it is capable of bypassing vaccines – Chronicle

Very contagious and now rampant across Europe, the Delta variant is scary. But unfortunately it’s not the only variant on which you have to keep the headlights on. An article dedicated to the B.1.427 / B.1.429 variant, the Epsilon, was published just a few days ago in Science. The focus of the research was on the ability of the mutated virus to neutralize the antibodies generated with vaccines. And the news is not good.

The Science article “SARS-CoV-2 immune evasion by the B.1.427 / B.1.429 variant of concern” calls it a “variant of concern (VOC)”. It was first identified in early 2021 in California and detected in other 44 countries (also in Italy but only in two cases). The variant is the result of three mutations present in the S glycoprotein, which forms the now famous “crown” protuberances of the virus and which is the “tool”, the key, with which the virus attacks cells by binding to the Ace2 receptor.

To understand why the new variant can circumvent the effect of vaccines, it is important to remember that RNA vaccines cause the organism that receives them to start Spike protein synthesis to stimulate the production, by the immune system, of specific antibodies who then recognize the Spike protein when they “meet” it. The problem arises when a variant has mutations that are potentially able to “bypass” the antibodies produced by the body after receiving the vaccine (but also by those produced by the actual infection). And that’s what the Epsilon variant would seem to do. It has been shown, in fact, that the three mutations present on the Spike protein of variant B.1.427 / B.1.429 I am able to induce one modest but significant reduction in the neutralization power of antibodies induced by the vaccine.

The neutralization power of the antibodies against the Epsilon variant was then compared with the neutralization power against the virus with the G614 S mutation (mutation capable of improving the ability of the virus to bind to the ACE2 receptor), against the original form of the virus. (D614 S), against B.1.351 (South African variant), B.1.1.7 (Indian variant) and P.1 (Brazilian variant). The reduction in antibody netralizing potency was demonstrated using plasma collected, between 7 and 27 days, from 15 subjects who received the second dose of Moderna mRNA-1273 vaccine and from 15 subjects who received the second dose of Pfizer vaccine. / BioNtech BNT162b2.

The potency of neutralizing antibodies against the variant B.1.427 / B.1.429 S (the Epsilon in fact) was reduced by 2.4 times compared to that against the virus with the G614 S mutation after vaccination with Moderna, while it was reduced by 2.3 times after vaccination with Pfizer / BioNtech.

The same study also analyzed the plasma of 18 individuals, 5 of whom were previously infected with the wild type of Sars-CoV-2 who had received two doses of Pfizer / BioNtech BNT162b2 vaccine and whose samples had been collected between 14 and 28 days. after the second dose. Plasma neutralization potency was 2.9-fold reduced against the Epsilon variant compared to the native form of the virus, with a decrease comparable to that observed against the South African variant (3.2-fold reduction) and greater than that observed. with Indian and Brazilian (reduction of 1.3 times and 1.7 times).

It was also the plasma of 9 donors was analyzed convalescents, collected between 15 and 28 days after the onset of symptoms, which had manifested symptomatic Covid in early 2020. The neutralizing power of their plasma was reduced by 3.4 times for the Epsilon variant compared to G614 S, similarly to what was observed with the South African and Brazilian variant, while the neutralization for the Delta variant decreased by 1.9 times.

Therefore, according to this study, the three mutations present in the Spike glycoprotein of the Epsilon variant reduce the neutralizing activity of the antibodies also induced by the infection. The good news, however, is that those who are vaccinated risk having a lower reduction in the neutralization power of antibodies than patients. So there is one higher quality of antibody responses induced by vaccination compared to infection.

There are nine variants of Sars-CoV-2 reported in Italy so far. It indicates it the international bank Gisaid, in which the genetic sequences obtained in countries around the world. Currently the alpha variant (B.1.1.7), identified in October 2020 in Great Britain, is still the most common in Italy even if in the space of a few days it dropped from 53.5% to 44.3% of the total sequences deposited. Its carrier version of the E484K mutation is being monitored and is on the rise. The second variant by diffusion is the Delta, indicated with the initials B.1.617.2 and identified in India, it has rapidly spread to about a hundred countries thanks to the great efficiency with which it is transmitted, estimated between 50% and 60% higher than the Alfa variant.

Both the Alfa and the Delta are so-called Vocs (Variants of concern), variants that cause concern and are followed closely around the world. The Gamma variant is also a Voc and circulates in Italy, indicated with the initials P.1 and identified at the beginning of 2021 in Japan and then in Brazil. The Beta variant (B.1.351) is also present in Italy, identified in South Africa and capable of spreading with an efficiency greater than 50% compared to the original virus and especially among young people.

They are classified as variants under study, that is, as Vui (Variants under investigation) the other five reported in Italy. Among these, the only one of which sequences have recently been deposited is the Eta (B.1.525), identified for the first time in Nigeria and which corresponds to 1.5% of the sequences deposited by Italy. The deposited sequences of the variant correspond to 0.4% Lambda (C 37), identified in Peru. The other variants, of which there have been reports in Italy in recent weeks, but with no recent genetic sequence, are Epsilon, indicated with the initials B.1.429 and B.1.427, identified in California; the Iota (B.1.526) identified in New York and the Kappa (B.1.617.1) and identified in India.

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