New COVID-19 variant found in South Africa: massive mutation or avoidance of human defense
2021-11-26
According to foreign media reported on November 24th, scientists have issued a warning that a "very large" mutation of COVID-19 mutation strain "quietly appear", in the multinational epidemic "reappearance peak", such a new variant of the emergence of the strain or "one disaster after another". ▲ b.1.1.529 strain had 32 mutations in spike protein Shocked scientists For the first time, both mutations appeared in one strain at the same time Although genome sequencing shows that so far, only 10 cases in 3 countries and regions have been confirmed to be infected with the virus named b.1.1.529, it has aroused "serious concern" of scientists, because 32 spike protein mutations have appeared in this new mutant strain, and some of them help the virus escape immunity. Spike protein is a key part of the virus. COVID-19 recognizes human ACE2 protein into human cells through it. At the same time, most of the existing new crown vaccines also attack human viruses by training human immune cells to identify spike proteins. The mutation of spike protein will affect the ability of virus to infect cells and spread, but it will also make it more difficult for immune cells to attack pathogens. To the scientists' surprise, the B.1.1.529 COVID-19 variant contains two mutations in the Flynn protease cut site - P681H (appeared in Alpha, Mu, some Gamma, B.1.1.318 mutant strains), and N679K (seen in C.1. 2). Dr. Tom peacock, a virologist at Imperial College London, tweeted that this was the first time he had seen two mutations appear in one strain at the same time. He pointed out that the mutation of this new mutant strain is "very terrible" and may be "more terrible than all previous new crown mutant strains", including delta strain, which is currently dominant in the world. In contrast, there were 16 mutations in the spike protein of delta virus strain. It is reported that B.1.1.529 infection was first collected in Botswana in November 11th. There are 3 confirmed cases in the country. Three days later, on November 14, South Africa recorded the world's first case of b.1.1.529 infection, and another five people have been confirmed in South Africa. In addition, one case was found in Hong Kong. A 36 year old man traveling to South Africa stayed in South Africa from October 22 to November 11. When he returned to Hong Kong, he tested negative, but he tested positive during isolation on November 13. Scientists say a single case in Hong Kong has just returned from a trip to South Africa, raising concerns that more viruses may have spread through international travel. "The export to Asia means that infection may be more common than the results of current gene sequencing," Dr. picock wrote In addition, he said: "the extremely long branch length and the incredible and amazing number of spike protein mutations suggest that b.1.1.529 may be a real concern (predicting escape from most known monoclonal antibodies)." ▲ b.1.1.529 strain has caused "serious concern" of scientists Or evolved from AIDS patients. This confirms the previous concerns of scientists Ravi Gupta, Professor of clinical microbiology at Cambridge University, said that the two mutations in b.1.1.529 increased infectivity and reduced antibody recognition ability. Judging from the current mutation, this is indeed a problem worthy of attention. However, he said that one of the key characteristics of the virus is not clear, that is, its infectivity, because this is the key reason for the dominance of the delta variant. "Immune escape is only part of what may happen". Scientists say they will pay close attention to the new variant to see if it has accumulated momentum or signs of wider dissemination. Some virologists have begun to feel deeply worried about the situation in South Africa. They said that at present, the b.1.1.529 infection cases in South Africa are from Gauteng Province, and the local cases have surged recently, which is likely to be driven by a new mutant strain, because the new cases have suddenly increased in very local areas. Moreover, in the existing cases in South Africa, one of the patients is a female infant under the age of one year, which means that family transmission has occurred. Professor Francois Baloks, director of the Institute of genetics at University College London, said that a large number of mutations in the B.1.1.529 variant were apparently accumulated in a single outbreak, suggesting that it might have evolved during chronic infection in patients with weaker immune systems, such as untreated AIDS / AIDS (HIV) patients. "I definitely think it's hard to recognize by neutralizing antibodies relative to alpha or delta," he said Baroque's statement confirms the previous concerns of scientists or has become a reality, that is, the "collision" between HIV and COVID-19 may complicate efforts to eradicate the new crown pandemic. Late AIDS patients may become a source of COVID-19 mutation and even become "the world's mutant virus factory". According to the Red Star news report, in the 216 days, a South African woman with advanced HIV had 32 mutations in COVID-19, including 13 critical spike protein mutations. At that time, scientists pointed out that there may be a link between the frequent occurrence of new varieties of COVID-19 and the high prevalence of AIDS in the Natal province of South Africa. More than 1/4 of the adults in the region are HIV positive. However, Professor barox said that it is difficult to predict the spread of b.1.1.529 strain. Dr. picock also said that the current situation is not clear and should be closely monitored. "I hope it is just a strange poison cluster that is not easy to spread.". (Xinhua News Agency)
Edit：Li Ling Responsible editor：Chen Jie
Source：chengdu.cn
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