Saturday, April 18, 2020

DOES VIRAL MUTATION AFFECT VACCINE DEVELOPMENT?


SARS coronavirus


SARS coronavirus



The new coronavirus is still raging around the world, with more than 2. 2 million confirmed cases worldwide and more than157,468  deaths. Zhong Nanshan, an academician of the Chinese Academy of Engineering, once said that the vaccine is the fundamental solution to the new coronary pneumonia.


However, while people expect vaccines and drugs to appear soon, the new coronavirus may also be mutating to adapt to the immune system of resistance of different populations.

Will the new coronavirus mutation affect the speed of vaccine and drug development? What is the variation law of coronavirus? To understand this, the "China Science News" interviewed Lan Ke, director of the State Key Laboratory of Virology of Wuhan University.

Knowing the chain of virus transmission can control the source of infection, recently, researchers at The University of Cambridge in the United Kingdom published research papers on the SARS-CoV-2 variants and transmission routes.

They believe that there are currently three types of variants in the new coronavirus, and each variant is linked to a specific country. Together, what do you think of the opinion of this paper?

Lan Ke: When we interpret a scientific paper, we need to read the original book, especially pay attention to the methodology used in the original text and make scientific judgments.

First of all, the sample size analyzed in this article is only 160 viral sequences. Compared with the 2 million people infected by the new coronavirus, the sample size is too small to represent all the evolutionary laws of the virus.

Secondly, this article uses bioinformatics methods based on gene sequence analysis, and virus tracing requires a lot of virological evidence and epidemiological evidence to form a complete chain. Simple calculation and analysis cannot reveal the whole picture.

Therefore, the ABC classification of this small sample and the link with the country are not accurate enough.

In particular, Class A in this article includes only 44 samples, including 9, in the United States, 16 in Mainland China, 5 in Australia, and 5 in South Korea. Based on the 44 samples indicating the country and region of origin of the virus, the evidence is insufficient.

A virus is a parasitic organism that cannot survive without its host. Therefore, virus tracing cannot simply analyze the virus sequence, but must also be analyzed together with the host species and sample collection time.

This is very difficult for the traceability of the acute infection virus, because of many key evidences of the virus transmission process are lost over time, and the final formation is only possible inference.

Years after the outbreak of many viruses, the cross-species transmission chain in nature is still unclear.

At present, it is 'believed' that most of the strong viruses that cause pandemics in humans come from wild animals, such as bats and chimpanzees.

Once these viruses are spread to humans due to improper human behavior, due to the lack of corresponding immunity of the human body, it is very easy to cause widespread outbreaks.

Therefore, the traceability study of the virus is more important to figure out which wild animals maybe its natural host and which animals are intermediate hosts, how they are spread to humans, and present a complete virus transmission chain, so as to control the source of infection and reduce the risk of another big outbreak.

In today's globalized world, no matter which country the virus breaks out, it will threaten global public health. Human beings are a community of destiny and the new coronavirus is a common enemy of human beings. 

It is expected that active global cooperation will be carried out to overcome the epidemic. Viruses adapted to humans are less pathogenic - China Science Journal. 

Academician Zhong Nanshan mentioned that the new coronavirus is already very suitable for the human body due to gene mutation. How should this be understood?

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