While the SARS-CoV-2 coronavirus pandemic is still raging in many countries, virologists continue to study the virus in order to improve the means of control put in place and, perhaps, accelerate the development of treatments and vaccines. Recently, a team of researchers has shown that the viral strain that is currently circulating is a mutated version of the one that originally emerged in China, having a higher and potentially more transmissible infectious power. In any case, if this result is important for a better understanding of the virus, it is not likely to change the current measures implemented or the management of infected patients.
The genetic variation of the new coronavirus that dominates the world today infects human cells more easily than the original strain that emerged in China, according to a new study published in the journal. Cell. Laboratory research suggests that this current mutation is more transmissible between people around the world compared to the previous iteration, but this has not yet been proven.
Researchers from Los Alamos National Laboratory in New Mexico and Duke University in North Carolina have joined the COVID-19 Genomics UK research group at the University of Sheffield to analyze genome samples published on GISAID, a resource international to share genome sequences.
Graph showing the evolution of the domination of the G614 strain over the initial D614 strain. Credits: B. Korber et al. 2020
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A more infectious viral variant
They discovered that the current variant, called D614G, slightly but powerfully alters the protein spike (advanced) used by the coronavirus to invade and infect human cells. Virologists first published their article on the medical preprint server bioRxiv in April, where he totaled 200,000 readers, a record.
Protein spike on which were indicated the different sites modified compared to the initial Chinese viral strain. Credits: B. Korber et al. 2020
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But it was first criticized because the authors had not proved that the mutation itself was responsible for its domination; the virus could have benefited from other factors or by chance. The team therefore carried out additional experiments, at the request of the editors of Cell. They analyzed data from 999 British hospital patients and observed that those with the variant contained more viral particles, but without changing the severity of their disease. Laboratory experiments have shown that the variant is three to six times more capable of infecting human cells.
On the same subject : COVID-19: The virus has already mutated into more than 30 different strains
Additional data needed to assess the scope of the outcome
But everything at this stage is only likely: the experiments in vitro often do not replicate the dynamics of a pandemic. To our knowledge, although the variant currently circulating is more “infectious”, it may or may not be more “transmissible” between people. Anyway, says Nathan Grubaugh, virologist at the Yale School of Public Health, the expansion of the variant, whether by natural selection or by chance, means that this variant is now the pandemic.
In a report, Grubaugh added that, for the general public, these results do not change much. ” Although there are still significant studies needed to determine if this will significantly influence drug or vaccine development, we do not expect D614G to change our control measures or worsen individual infections “Concludes Grubaugh.
Sources : bioRxiv
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