The second coronavirus strain may be more infectious, but some scientists are skeptical

The commotion of mutations in the virus that causes COVID-19, and how it makes COVID-19 more infectious, has existed since the early stages of the pandemic. Preprint studies of specific mutations, including “spikes,” interspersed with SARS-CoV-2 pathogens had previously been of interest, but the study is now peer-reviewed, cell.. The paper details one amino acid change in the virus It may have made it more infectious.. However, virologists are far from consensus on the possible role of this mutation.

This paper shows that in SARS-CoV-2 a single amino acid changes from D (aspartic acid) to G (glycine). Spike protein The use of such viruses to grab human cells is the key to how pathogens are infectious. “Spike proteins play a very important role in viral biology,” says Bette Korber, a computational biologist at Los Alamos National Laboratory and lead author of the new paper.

Korber and her colleagues reached this conclusion after adopting multiple approaches to examine the two strains. First, a statistical analysis is performed to show how the mutant virus (often referred to as the “G strain”) gains an advantage over multiple continents and coexists with the original version of SARS-CoV-2 or “D”. Better than the “stock”. Researchers then tested the viral load of individuals with COVID-19 at the Sheffield Teaching Hospital NHS Foundation Trust in the United Kingdom. As a result, it was found that the G strain produces more virus in the human body than the D strain. However, the former did not lead to a higher hospitalization rate, which means that it did not clearly cause more serious illness. Finally, team members created “pseudotyped” pathogens by implanting SARS-CoV-2 spike proteins containing either D or G amino acids into other disease-causing viruses. They tested these pseudotyped viruses by infecting human cells in laboratory dishes, and the results suggested that those with G were more infectious. But examining cells in a dish is not the same as testing them with “multiple cell types that have an immune system in the human body,”” Emma Hodcroft, a molecular epidemiologist at the University of Basel, Switzerland. Says. the study. “We really have to be careful about how we reach conclusions.”

The authors of the study say that current vaccine and therapeutic efforts do not claim that they will be useless because most are based on the original D strain. “But that means you need to check carefully [the effects of the mutation] Make sure it doesn’t have any impact,” says Cober. “You want to be certain [therapies and vaccines] It works great against today’s viruses as well as yesterday’s. “

Meanwhile, some scientists are concerned that the results are overly interpreted. Nathan Grubaugh of Yale University and his colleagues wrote another paper cell On the same day as the layout of Kober’s study Limitations to findings and alternative explanations.. Others have commented on the conclusions of Korber and her colleagues. social media When their paper was first released as a preprint.

Grubaugh’s paper points out that if a strain is simply more common, it does not necessarily mean that it is more infectious. The researchers write that the higher frequency of G-shares “may be explained by chance.” They also said, “In the case of SARS-CoV-2, there is good evidence that a small number of infections are responsible for the majority of infections,” and most of the infections that caused the outbreak happen to be associated with the G strain. He added that there is a possibility. It is possible that tensions (generated in Europe) spread more and more often to other parts of the globe, leading to its global dominance. “It’s like a really difficult unwinder,” Hodcroft says.

Regarding the amount of virus detected in the human body, the method used by the Cover team says “it does not measure infectious virus, which is a problem of infection”. Vincent Racaniello, a virologist at Valeros Medical Surgeon in Colombia, says. Universities not involved in either cell paper. With viral infections, “There are times when you actually produce the infectious virus. But then the infection basically stops. And what remains is a degraded body that remains in the body for a long time. “It’s a virus.” The method adopted by Korber and his colleagues is “not enough experimentation to prove that it promotes infection,” he added, as it can detect degraded viruses.

It is still unclear whether the G strain will affect the efficacy of potential vaccines or treatments. A paper by the Korber team shows that antibodies from people who were infected with SARS-CoV-2 fight against both strains. “This was a really encouraging step, but we need to do more work,” she says.

Since there are several preprinted papers that suggest the G strain, the debate about the newly identified mutations and their implications will probably continue May More Contagious.. However, only Kober’s work has been peer reviewed so far.

“The round trip between these scientists is actually normal, and this is how science evolved,” Hodcroft says. “Not all science is in disagreement. [surveyed] If you are a scientist, they will give you the same general idea about viruses. “

“I’m not saying what they’re suggesting is plausible,” says Racanello. “This may prove at some point, but I’ll be fine.”

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