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More than 40 countries, including India, have banned travel to and from the UK, a move that several scientists said was necessary in view of the rapid spread of the new viral strain, VUI-202012/0, which was detected on September 21st.
According to Jeremy Farrar, director of the London-based research charity Wellcome Trust UK, there is currently no indication that the new strain eludes treatments and vaccines.
“However, the mutation is a reminder of the virus’s power to adapt, and that cannot be ruled out in the future. Acting urgently to reduce transmission is critical,” Farrar said in a statement.
The European Center for Disease Prevention and Control (ECDC) announced Sunday that a rapid rise in a variant of SARS-CoV-2 with multiple mutations in the spike protein has been observed in the UK.
“Preliminary results from the models reported by the UK on 19 December suggest that the variant is significantly more transmissible than previously circulating variants, with an estimated increase in reproductive number (R) of 0.4 or more with an estimated increase. of transmissibility of up to 70%, “EDC said in a statement.
The R number denotes the expected cases generated directly by a case in a population, while transmissibility is the ability of a virus to be transmitted from one person to another. The ECDC, however, said there is no indication of an observed increased severity of the variant-related infection. The assessment is challenged by the fact that most cases were reported in people younger than 60 who are less likely to develop severe symptoms, he said.
“The new strain of the virus is known to have 13 mutations in the peak protein of which the N501Y mutation is responsible for spreading 70 percent faster than previous versions of the virus,” said Deepak Sehgal, professor and chief. from the Department of Life Sciences, Shiv Nadar University.
N501Y is the mutation. Position 501 in the amino acid chain of the peak protein has been altered from asparagine, indicated by the letter N, to tyrosine, represented by the letter Y, hence N501Y, the scientists explained.
The spike protein is a corona protein of the virus that comes into contact with human cells to enter and infect. Sehgal noted that the new variant has mutations in the spike protein that all three major vaccines target. The three main vaccines are Moderna, Pfizer, and Oxford-AstraZeneca.
“However, vaccines produce antibodies against many regions in the spike protein, so it is unlikely that a single change will make the vaccine less effective,” Sehgal told PTI. Over time, as more mutations occur, the vaccine may need to be modified.
“This happens with seasonal flu, which mutates every year, and the vaccine is adjusted accordingly,” Sehgal explained. The SARS-CoV-2 virus, however, does not mutate as fast as the flu virus, he added.
Virologist Upasana Ray agreed with Sehgal, noting that there is not enough evidence to suggest that these mutations may affect the efficacy of current vaccine candidates. “It is important to remember that we do not know if this variant is a ‘serotype’ (variant),” Ray, senior scientist at CSIR-IGIB Kolkata, told PTI.
He explained that it is still unknown whether the new strain interacts with the host’s immune system differently compared to other existing variants. As such, to date there is no evidence that this variant alters the severity of the disease, either in terms of mortality or the severity of COVID-19 cases for those infected. He said that the structural proteins of a virus are responsible for the binding of the virus receptor and coreceptor in cells, which ultimately leads to the entry of the virus into host cells. “Therefore, changes in the structural protein could influence the strength of virus-receptor interactions and, therefore, infectivity,” he added.
The researchers said the experimental data suggested that the coronavirus N501Y mutation increased infection in mice and led to increased infectivity and virulence. “The threat of mutation in the spike virus can lead to more rapid entry of the virus into human cells increasing infectivity. Only an amino acid change from asparagine to tyrosine has made a difference in the strain improving its transmissibility,” added Sehgal. .
One of the most significant changes is an N501Y mutation in the spike protein that the virus uses to bind to the human ACE2 receptor through which the virus enters the body. “Changes in this part of the spike protein can, in theory, make the virus more infectious and spread more easily between people,” Sehgal said.
The researchers supported temporary travel bans to and from the UK to halt the spread of the new viral strain. The ECDC said there were indications of a more widespread occurrence of cases across the UK, adding that some cases were also detected in other countries. Italy reported that a citizen who had recently traveled to the UK tested positive for the new strain of the virus. “The strain has also been found in Australia, South Africa, Brazil and Italy. It is absolutely essential to stop the journey to spread this new strain around the world,” Sehgal said.
“Countries where this strain of virus has not been reported may be because tests were not performed and therefore are not known. Therefore, to determine the existence or spread of the strain, all countries require extensive testing of circulating viral strains, “he added.
The new strain was first detected in the UK in September. In November, about a quarter of the cases in London were the new variant. This reached almost two-thirds of the cases in mid-December.
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