Let’s think of a virus as a “little mutant” that we carry inside. That constantly mutates. At your own pace. With different consequences.
In a month, at least 5 new variants of coronavirus appeared or spread, increasing the rate of infections, mortality and raising doubts about how they could affect treatments and vaccines.
The laboratories ensure that mutations are part of the natural history of all viruses. That those “little mutants” always did what they do best: mutate. But in this global context, not only does the number of cases and deaths increase rather, they impact the economy by deepening the lockdown and closing borders. Can they become the main obstacle to stop the Covid?
Claudia Perandones is the renowned geneticist who coordinates the ANLIS Malbrán teams responsible for testing and decoding the virus genome in Argentina. For his expertise faced with “mutants”, he knows that it is scary to hear of “new strains” and vaccines that are already made. That is why he clarifies that mutations create variants. And that vaccines, if necessary, can be recalibrated.
“Variants are a set or constellation of mutations or changes in the genome of the SARS-CoV-2 virus that occur jointly or in association. Variants that have generated concern are called VOCs (variants of concern, in English)”, Explain.
Which are? The most mediatic these days. The UK VOC and the Rio de Janeiro VOC. Both were detected in our country.
That of the United Kingdom is B.1.1.7, which has 23 mutations of which 8 are located in the viral spike. Among those mutations, three generate the most concern.
“One is the N501Y mutation, which is located in the key contact area for binding with the human ACE2 receptor, which is the gateway for the virus to enter human cells.” This mutation gives it greater affinity or avidity to bind to cells and would be responsible for the virus having 70% more transmissibility.
Does this mutation allow Covid to escape the antibody response of those that were previously infected and also of vaccines? No.
Recent studies from the School of Medicine of Mount Sinai from New York -with whom ANLIS Malbrán has a strategic collaboration- demonstrated that this mutation “is sensitive to the response mediated by antibodies”, both in the plasma of individuals recovered from the disease as in the serum of vaccinated people.
“This finding is very reassuring in relation to the fact that currently developed vaccines are effective in protecting against the United Kingdom variant”, Perandones brand. Two other worrisome mutations within this variant raised alarm: the 69-70 deletion and the P681H mutation. But neither do they escape the vaccine or plasma.
Does the UK variant, which is in Argentina, conditions higher mortality? “Although Prime Minister Boris Johnson raised this Friday the possibility of a greater fatality, the reality is that there is no scientific evidence for such a claim. It is logical and expected that the increase in the number of cases produced by this variant inevitably conditions, an increase in the number of deaths. But both the research groups of Public Health England, Imperial College London, among others, do not allow to confirm what the premier said “, says Perandones.
_Are the vaccines developed for SARS-Cov-2 effective against the appearance of variants?
-Both the CEO of BionTech (Pfizer), Ugur Sahin, as that of Moderna and the Director of the Russian Fund for Direct Investment, Kiril Dmitriev, confirmed that the statistical modeling and tests aimed at determining what the spatial conformation of the spicule with mutations it could adopt, showed that currently developed vaccines are effective in neutralizing the UK variant.
Perandones also highlights that this week Pfizer published its study carried out with the University of Texas, Medical Branch at Galveston, which proved that this vaccine “It is effective for all those variants that contain the N501Y mutation.”
This mutation is present in the UK variant (B.1.1.7) and also in the South African (501.V2) and Brazil variant identified in Japanese tourists (B.1.1.248, or P1 variant). In that study, the researchers evaluated serum from 20 vaccinated people and determined that it was capable of neutralizing them.
The concrete thing is that the British variants are more contagious: they were identified in September and now have a high prevalence in 60 countries. How could the UK mutations have been generated? Again, and simply, by the nature of these little mutants. But there was something unusual.
“That the UK variant differs by 23 mutations from the original Wuhan, China strain, is much higher than current estimates of the virus’ molecular clock of around two mutations per genome per month. The unusually high number of mutations spicule protein and other genomic properties of this variant indicate that it was not the result of gradual accumulation of mutations in the UK (as more infections occurred). A possible explanation for the emergence is a prolonged infection with SARS-CoV -2 in a single patient, potentially with reduced immunocompetence, “says Perandones.
– An eventual new mutation could lead to existing vaccines today becoming placebo?
-Most of the vaccines for SARS CoV 2 were developed through genetic engineering strategies. This allowed to accelerate the times but it would also allow, if necessary, to introduce modifications in the genomic sequences of the viral spicule, which is the target that everyone chooses as the main immune stimulus for the organism to produce antibodies “, he closes. Thus, the race against the “little mutants” would never start from 0.
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