In the global action against the COVID-19 epidemic, human beings have learned more and more about this deadly virus. A recent paper published in the Proceedings of the American Academy of Sciences suggested that the current COVID-19 virus has developed three subtypes based on the immune capacity of different populations. Academician Zhong Nanshan also said that the COVID-19 virus has adapted to the human environment through mutation, and it has become increasingly infectious. What impact will the constant mutation of the COVID-19 virus bring? Will there be “super variants” in the end, as worried online?
The most primitive virus is mainly circulating in the United States and Australia
According to a paper published in the Proceedings of the American Academy of Sciences, the research team of the University of Cambridge in the UK, after analyzing the genetics of 160 COVID-19 viruses from all over the world, concluded that “the most primitive COVID-19 virus mainly appears in the United States and Australia. Not in Wuhan. ” However, the paper also emphasized that the evidence currently collected by various parties in the world cannot determine the specific location of the virus’s original origin.
The main author of the paper, Fellow of the Royal Society of British Biology and geneticist of the University of Cambridge, told the Global Times that the content of the paper currently published is based on tracking 160 global genomes from December last year to March this year. The aim is to map the evolution and spread of viral genes.
This paper divides the currently discovered COVID-19 viruses into three types, A, B, and C, according to their evolutionary relationship. Among them, the type A, which is closest to the coronavirus genes carried by bats and pangolins and was first transmitted to humans. Although it was discovered in Wuhan, it is not the same as the COVID-19 virus gene that is popular in mainland China. Type A viruses mainly appear in the United States and Australia. “In the United States, at least 2/3 of the confirmed cases are of type A.” What is prevalent in Wuhan is actually a type B virus that mutated from the original virus. The COVID-19 virus circulating in European countries such as France, Spain, Italy and the United Kingdom is a type C that evolved from type B. It has not been found in mainland China, but it has appeared in Singapore, Hong Kong and South Korea.
For the report released by Cambridge University, Western academic circles and the media are very concerned. A large number of netizens followed the relevant report of the British “Metropolis Daily” and said that this time they realized that the virus behind COVID-19 is so complicated. The previous “Wuhan virus” statement is indeed unfair. There are also comments that the greatest value of the Cambridge University report is that all people affected by the epidemic can carefully read the report and then think about the credibility of various “viral theory”.
Foster emphasized that the COVID-19 virus has too many rapid mutations, making it difficult for researchers to fully trace the virus’ family lineage. His team is currently expanding the research sample to 1001 viral genomes. Although the research results have not yet been released, some certainties and possibilities are already in sight. He admitted that some other international colleagues insisted that “the virus spread in Western countries is likely to originate in Wuhan initially,” but he is confident in his team ’s research conclusion: “It is certain that the first COVID obtained from Wuhan The -19 virus belongs to type B, rather than the most primitive type A. Type A virus once existed in Wuhan, but only a minority. ”
Foreign virus subtypes are more contagious?
Why do more A viruses appear in the US and Australia? Forster believes that this is related to the genetic and immune system of the local population. In layman’s terms, type A has no simple surviving soil in Wuhan, and eventually mutates into a more aggressive type B. In the United States and Australia, Type A quickly found a large number of surviving hosts, so it spread rapidly.
Yang Zhanqiu, director of the Institute of Medical Virology, Wuhan University, told the Global Times on the 12th that the different virus subtypes prevailing in different places are indeed related to ethnicity. Adaptability to the immune system of a population in a certain area. In addition, it also has a relationship with the local host animal and environment, such as which animal it comes from, because the virus has to adapt to the animal host and environment.
Academician Zhong Nanshan emphasized in an interview recently that the COVID-19 virus has been very adapted to survive in the human body through genetic mutation, so its spread is relatively strong, and it has a mortality rate of more than 20 times compared to influenza. This problem is indeed worthwhile. Value. Many people are worried about this, is it more contagious for patients returning from abroad to carry mutant viruses?
Yang Zhanqiu believes that foreign viral subtypes may only be susceptible to the local population, not to the Chinese, and are unlikely to cause a pandemic in China. He said that the rapid spread of the virus is related to the amount of virus on the one hand and close to the mobility of people on the other. There are fewer new cases in China now because we have blocked the spread of the epidemic. China has adopted strict isolation measures for people returning from abroad, and the chances of spreading the virus brought into the country from abroad have been reduced, preventing the spread of the virus. “Even if the virus subtypes circulating abroad are brought back to the country, it is actually more suitable for the people in the original area. If you want to be popular among the Chinese population, you need an adaptation process. So we do n’t have to worry about people who return from abroad bring more terrible Viruses, as long as the conditions and environment for preventing and controlling the virus and blocking the transmission of the virus are good enough. ”
“Super variant virus” is unlikely
As the COVID-19 epidemic continues to spread around the world, there are still concerns that the virus will continue to mutate in the long-term spread, and even “super variants” appear. Yang Zhanqiu said that it is possible that more subtypes of COVID-19 virus will appear in the future, but it will not appear immediately. As for whether there will be a “super variant” in the end, his judgment is “not necessarily”. Because the more virus subtypes appear, the more adaptable the virus is to people, and its ability to spread is reduced, but it is not easy to cause a pandemic. In general, there is no situation where the more subtypes the more severe the virus. “But it is worth noting that if the mutation site of the virus happens to be a very fatal location, a larger outbreak is possible.”
What kind of influence does the non-stop mutation of the COVID-19 virus have on the current war epidemic work? Yang Zhanqiu said that different virus subtypes are closely related to its pathogenicity. For example, the subtypes popular in Italy have higher mortality and stronger pathogenicity. The subtypes popular in South Korea and Japan have weaker pathogenicity and death The rate is correspondingly lower. “Different subtypes cause different disease manifestations, and the corresponding treatments are also different. At present, the mutation of the COVID-19 virus has a greater impact on the vaccine.” For example, the popular virus subtype in China is type B, If we use a type B vaccine to prevent infection in areas where the type A virus is endemic, the effect is not good. “This is similar to the flu virus that changes every year. If the previous flu vaccine is used to prevent the outbreak of the second year, it will not work at all. Yang Zhanqiu believes that after the emergence of virus subtypes, a variety of corresponding vaccines need to be developed. Of course. Theoretically, there may be a vaccine that can act on all three subtypes of viruses at the same time, but the difficulty of developing this vaccine has increased.
Relatively speaking, the impact of virus mutations on drugs is not very large, because drugs are mainly for the process of virus reproduction, and vaccines are for the entire virus. Viral infection is related to the receptor, as long as the drug blocks the viral receptor at an early stage, no matter what subtype of virus, there is no way to infect.