The Danish mink has put a serious pig on humanity. The new coronavirus mutation, first discovered on a farm in North Jutland, was the first significant mutation to alter the properties of SARS-CoV-2. Norok were liquidated en masse, although later they apologized. Alas, the new strain is more infectious and presumably more aggressive. The saddest thing is that it is resistant to antibodies that are produced on the usual SARS-CoV-2, which complicates the work of vaccines and threatens those who have already had the old version.
The mutant coronavirus was recorded in Denmark on minks, transmitted to humans and is now spreading to various countries. It is already in Denmark, the Netherlands, Spain, Sweden, Italy, the USA and, presumably, in Israel.
The Danish authorities said that five cases of the new strain were reported from mink farms and 12 cases in humans, and that there are between 15 and 17 million minks in the country. A total of 214 human cases of COVID-19 associated with mink farms have been identified in Denmark, although not all were associated with the new strain.
“This is the first significant mutation of a coronavirus with altered properties,” said Alexander Kudryavtsev, bioengineer, junior researcher at the IBCP RAS. “Studies have shown that it leads to the formation of different properties of the virus from the previous type. Significant changes have appeared in the virus genome due to which also changed the properties of the virus. Based on these changes, the virus was singled out into a separate group, which was named Cluster 5. ”
According to Alexander Kudryavtsev, the most significant change took place in a site called the “receptor-binding domain”, which gave the virus fundamentally new properties of greater resistance to neutralizing antibodies that are produced for coronavirus. Another distinguishing feature of the mutant is its high virulence – it multiplies faster at a lower initial dose, which makes it more infectious. That is, it is transmitted by already known ways, but now it clings to the receptor on the cells better.
What is the threat of resistance to neutralizing antibodies? For example, if a person has already been ill with the “corona” and has developed antibodies to the first version of the virus, the new version is able not only to bypass this line of defense, but also theoretically can cause the same ADE (antibody-enhancing) effect, the possible danger of which scientists spoke with the very beginning of the pandemic. In other words, re-infection can result in a more severe course of infection with an increased risk of death. “But even if there is no ADE effect, it cannot be ruled out that additional virus mutations will not appear in six months or a year, and that we will not meet with an even greater risky option,” the scientist emphasizes.
The resistance to neutralizing antibodies of the first version of the coronavirus makes the work of vaccine developers much more difficult. “Now, in theory, all candidates should undergo a stress test for the real threat of antibody-dependent amplification, because antibodies will be produced, just not for what is needed. A situation may arise, like with the Dengue virus, when re-infection with the virus (like and post-vaccination) increases mortality if the antibodies are incorrect, “Kudryavtsev notes.
Despite the fact that virologists have always emphasized that over the course of the pandemic, the virus should, in theory, weaken its properties, this has not happened yet. “And now we see that everything is the other way around. By the way, the same thing happened with the Spanish flu. The first wave was less aggressive than the second. And it was in the second that, despite the military censorship, they began to talk about it. There was a pandemic in America, however it became known only when it was brought to Spain, where they started talking about it and called it “Spanish flu.” In the first wave in the United States, the virus did not take as many lives as it did later, when a more aggressive strain with genes altered in America appeared. ” – continues Kudryavtsev.
Can we expect dangerous mutations from other animals around us? Alas, yes. “We know that mice and cats have various forms of coronavirus disease (others). And no one can rule out that some form of the new SARS-CoV-2 will pass to them. There are reports that cats and dogs may be carriers a new coronavirus, but it cannot multiply aggressively, like in minks, in these animals, and it does not show symptoms.And once in the minks, the virus mutated inside them.
In addition, today ferrets and hamsters are getting sick with the new coronavirus, they cough, their lungs are affected. These animals have become the standard model for testing vaccine protection, ”says the scientist.
Of course, there is a possibility of the virus mutating even inside a person. And one such case has already been reported by The New England Journal of Medicine. In one of the Boston hospitals, a 45-year-old patient with a rare autoimmune disease (thrombus formation accelerates) was observed in whom SARS-CoV-2 returned three times after infection, and acquired new mutations during his stay in his body.
His virus carrier was recorded on day 72 after infection (this was considered a continuation of the medical history), but, after negative PCR, on the 105th day after infection, the tests were again positive.
The next time this happened on the 128th day, and then on the 143rd. Each time he developed new symptoms – first a high fever, then abdominal pain and pulmonary bleeding, then inflammation of the subcutaneous tissue (for the third time he needed mask oxygen, then mechanical ventilation, and on the 154th day the patient died). Scientists compared the sequences of the data obtained in the swabs and found that the virus mutated!
From the first to the second positive test, 11 nucleotide substitutions appeared in his genome, from the second to the third – 10, from the third to the fourth – 11. In particular, the mutations were in the same receptor-binding domain. Scientists explain that the virus persisted for a long time in the patient’s body, and therefore rapidly evolved.
This case suggests that the “crown” will present us with many more surprises …