Jun 16, 2020 – As protests against the killing of George Floyd wind down, a stark reminder that a global pandemic looms overhead. Now it is being claimed that coronavirus has made a new mutation, and is now far more infectious than the first wave.
In more than half of the studied strains of the novel coronavirus, this widespread mutation was found, which improves its ability to penetrate cells from 2.5 to 8 times. Molecular biologists from the New York Genomic Center and New York University claim this, the results of their work are published in the bioRxiv electronic scientific library.
“The widespread D614G mutation significantly accelerates the transmission of the virus between a wide variety of types of human cells, including cells from the lungs, liver and intestines. One of the reasons for the increased infectiousness of the virus may be that this mutation makes SARS-CoV-2 more resistant to human enzymes, ” the researchers write.
Today it is known that coronavirus accumulates mutations at about the same rate as the causative agent of influenza. However, how these mutations affect the infectiousness and other properties of the virus, scientists do not yet reliably know. In early March, Chinese biologists said that the virus could be divided into two subtypes – S and L, which differ from each other in the severity of symptoms and the speed of spread. Other scientists doubted this, noting that changes in the general gene pool of the virus could be caused by various random processes, rather than real differences in the infectiousness of these SARS-CoV-2 subtypes. In May, scientists from Britain and Australia showed that three varieties of the virus circulate in the human population at once.
According to scientists from New York University under the leadership of Neville Sanjana , about 70% of the coronavirus strains of all three subtypes circulating today have a common mutation in the S gene, which controls the production of proteins of that part of the SARS-CoV-2 membrane that is directly related to its penetration into the body. Judging by its rapid spread, this “error” in RNA, the so-called mutation D614G, is supposedly useful for coronavirus. However, scientists did not know before what exactly she was changing.
Experiments have shown that this change in the RNA of the virus sharply increased its infectivity. In particular, the number of luminous intestinal cells increased by about 2.5 times, lungs by five times, and liver cells by almost eight times. However, she four times reduced the likelihood that the immune system will begin to recognize the spike-like protein of the virus and develop antibodies to it.
In addition, scientists found that enzymes in the human innate immune system destroyed the coat proteins of this version of SARS-CoV-2 more slowly than other types of the virus. As suggested by Sanjan and his colleagues, this can accelerate the formation of new viral particles and their distribution throughout the body.
This is why it is claimmd the D614G mutation has become dominant in such a short time. Major cities have witnessed mass protests where social distancing norms were not observed. The CDC has said in recent days that this will make the coming second wave of the coronavirus far more problematic.