The variant of the SARS-CoV-2, which dominates in the world today, infecting more easily the cells as the one that appeared originally in China, which is likely to make it more contagious among humans, although this remains to be confirmed, according to a study published Thursday in the journal Cell.
“We still do not know if a person is doing less well with it or not,” commented Anthony Fauci, director of the Institute of infectious diseases american journal Jama. “It seems that the virus replicates better and might be more transmissible, but we are still at the stage of trying to confirm it. But there are very good geneticists viruses that work on it. ”
After his release from China and his arrival in Europe, a variant of the new coronavirus, which mutates constantly as a virus, became dominant, and it is this european version which is then installed in the United States. The variant, named D614G, relates to a single letter of the DNA of the virus, at a place controlling the point with which it penetrates the human cells.
Genetic mutations of the coronavirus are tracked around the world by researchers, that sequencing the genome of the virus they found and share them on an international database, GISAID, a treasure trove of more than 30,000 sequences to this day.
The researchers of the new study, from the universities of Sheffield and Duke, and the Los Alamos national laboratory, were established in April as D614G dominated now and then said, with some alarm, that mutation made the virus more transmissible “. They had put their results online on a site of preprints the scientists.
But that assertion was criticized because the team had not demonstrated that the mutation itself was the cause of the domination; it may be that it has benefited other factors or chance. Scientists have therefore carried out research and experiments further, to demand of the editors of Cell.
They first analyzed the data of 999 patients in the uk hospitalized because of the Covid-19 and observed that those with the variant had more viral particles in them, but this does not change the severity of their illness — a new encouraging.
On the other hand, laboratory experiments have shown that the variant was, however, three to six times more capable of infecting human cells.
“It seems likely that this is a virus more capable of “, said Erica Ollmann Saphire, who has conducted one of these experiments, the La Jolla Institute for Immunology.
But it’s all in the “unlikely” : an in vitro experiment can not reproduce the actual dynamics of a pandemic.
The conclusion the more strict is so that if the coronavirus that is currently circulating is probably the most ” infectious “, it is not necessarily a more “transferable” between humans.
In all cases, write Nathan Grubaugh, of Yale university, and colleagues, in a separate article, ” this variant is now the pandemic “.
“D614G should not change our measure of restrictions or aggravate individual infections,” says Nathan Grubaugh.
“We are witnessing the scientific work in real time : this is an interesting discovery that affects potentially millions of people, but of which we do not yet know the final impact. We have discovered the virus six months ago, and we will learn many more things in the next six months. “