Discussion on the relationship between biodiversity and newly-emerged infectious diseases by Prof ZHANG Wenhong
2021/5/28 14:55:00 本站

Editor's note

May 22 this year marks International Biodiversity Day. CBCGDF and BGI have successfully co-hosted an online conference titled The Construction of Human and Natural Life Community from the Perspective of Global Environmental Crisis. Professor Zhang Wenhong was invited to the meeting and shared his thoughts on the relationship between biodiversity and newly-emerged infectious diseases. Thus, to meet CBD COP15 and promote global biodiversity protection, professor Zhang Wenhong's speech is shared for readers' reference.


Today, I would like to talk about the relationship between biodiversity and newly-emerged infectious diseases and measures we can take to deal with the COVID-19.

The existence of biodiversity serves as a fundamental basis for the occurrence of all infectious diseases today. Human beings are also part of the biodiversity in nature. For a long time, human beings have maintained a very balanced state with nature. So in the whole process of human evolution, we rarely talked about these pandemics before the birth of modern civilization. However, with the advent of industrial civilization, the migration of human beings, the emergence of cities and towns after the agricultural civilization, and the communication among continents, there is an extensive exchange between human and nature, among species. So many microorganisms in nature enter the human body.

Because there is a particular species barrier between humans and other species, many pathogens are not so easy to enter the human body. But in the long-term evolution process, some viruses or bacteria can cross the barrier to enter the human body. Further, the incidence of infectious diseases becomes possible with increasing density as people live. Once new infectious diseases enter human society, many problems can be caused. The diseases we see today occupy only a tiny part in the whole nature.

Suppose a huge tree is represented to show the diversity of species in nature. In that case, the diseases related to human beings that can only be detected are shown in the blue area, while the red area indicates the virus that we can find through virus cultivation. That means in the whole nature, the storage of virus is vast.

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If we can not maintain the ecological balance of nature but permanently destroy the diversity, more and more species in nature will invade human society. That's what happened this year with the outbreak of the COVID-19. Once the virus enters human society, the typical situation is that human beings will have a response.

After the emergence of human reactions, one of the natural reactions of the human immune system is to eliminate the virus. In the process of exclusion, a large number of inflammatory reactions will occur, and severe patients will die due to inflammation. In the process of continuous interaction with the virus, the virus is constantly adapting to humans. Therefore, in the survival of the human species, smallpox and influenza, which are very well known, are constantly adapting to nature and human beings before vaccines come out to reach a balance.

From the initial death of many people to the final establishment of an immune system in human society, the virus will gradually evolve, and finally, a very balanced state will be achieved. But a lot of people still die every year. So before the vaccine, whether smallpox or influenza, will cause a large number of deaths. This is the result of the exchange, adaptation and evolution of different species in nature. In the evolutionary process of all species, we will find that viruses or bacteria, if there is not a very good and specific method for them, such as vaccines, specific antiviral and antibacterial drugs, will cause global spread.

Take AIDS as another example. If we do not have a specific and effective anti-HIV method, the spread of AIDS will far exceed our expectations. Because after vaccination, under the pressure of this kind of immunity, the virus will continue to evolve. The re-adaptation of humans makes the bud of the virus constantly change, which will eventually lead to the long-term existence of the virus in human society. Then a considerable number of people will be infected every year. After infection, we will start to establish immunity again. Then the following year, new varieties will come out and finally reach a balance. This is a normal relationship between natural species and human beings today.

In this case, after the emergence of the new coronavirus, the world is monitoring its polymorphism. We will find that the D614G mutation is the first adaptive mutation in the polymorphism monitoring,which will change all strains in the world after a while. When these viruses spread in different areas, they begin to have a new mutation of their own. But these mutations do not mean that humans will lose control of these viruses because these mutations are random to a certain extent, and eventually, the virus that spreads fast will become a dominant group.

So whether it's D614G or those virus strains in the United Kingdom, the United States, India and South America, the transmission speed of these virus strains is several times or two to four times higher than that of the original strain. Still, it has not caused a complete escape of its resistance. It is a natural evolution process in the current virus evolution process. Here I'm showing you a mutation in D614G.

At first, we thought that D614G would lead to severe consequences, but today we find that it is not. Its mutation caused a slight increase in the speed of transmission. Now a mutation of D614G in the world, Europe has occupied almost all the virus strains, but these virus strains in the clinical face have not caused a significant increase in mortality.

So the mutation of these viruses is a very normal mutation process in nature. Every time in the process of transmission, there will be epidemic strains. After that, we saw the South African strain and British strain, and they all started from the D614G mutation. As the global epidemic is still spreading, we believe that an independent virus strain will form in different regions. Today, because the virus is no longer spreading in China, the evolution of virus strain in China has stopped. But in the future, when we re-start exchanges globally, it is still difficult to predict whether these virus strains will continue to have new subpopulations.

We are concerned about today whether the emergence of subpopulations will escape the group immunity we have built and the role of our vaccines. A better recent data is from the United States. Since March this year, mutations of British virus strains have accounted for more than 50 percent. So many people will ask whether there will be vaccine escape and the runaway of the United States epidemic because the UK strains in the United States account for more than 50 percent. So today, as we can see, it is like a random variation of the virus, and because of its rapid spread, the dominant strains do not escape the group immunity we have built and the immune protection by vaccine injection.

So today, for people who have been vaccinated in the United States, control measures like wearing masks or keeping social distance have been wholly loosened, which is also an excellent response to the current mutation.

A subpopulation that appeared in the United States has gradually occupied a more considerable advantage globally, but it does not cause complete escape to the immunity. What are we worried about?

Will the mutation caused by the Indian subpopulation, i.e., subpopulation 1.617, lead to an escape of our population immunity and vaccine? From the data of India, in the first three months from January to April this year, we will find that this virus strain accounts for more than 80% of the dominant position.

What is worrying now, the escape of vaccine or the escape from group immunity? According to the number of people infected in India, it is very far from population immunity. For the amount of vaccination in India, it is far from enough for the escape of the vaccine, and only more than 10% of the people vaccinated in the season. So for the emergence of strains' escape to vaccine, we haven't yet seen it in theory because the population's vaccination has not reached that level. Now, in the research, will the emergence of this strain change its pathogenicity and infectious change?

Now we find a slight increase, but the severity of the disease has not significantly changed. Because of the gradual improvement of medical resources, there is no increase in pathogenicity due to the mutation of the virus. From the scientific research of natural diversity, virus mutation is not to kill human beings because killing the host will not bring any benefits to the spread of the virus. So at present, only the virus strains with increased infectivity, rather than the virus strains with increased pathogenicity, may have advantages in biodiversity and virus evolution.

Of course, sometimes the opposite happens. But in most cases, for the new epidemic today, these new strains will have a certain degree of increase in transmissibility. For example, we see the California strain in the United States, increasing the infectivity by 20%. Well, the infectivity caused by strains in India has also increased to a certain extent.

Today we see that for the vaccine's performance against mutant strains, a vaccine from Biotech still has a 95 percent protection rate for British strains. This means that the virus now mutates before full-scale vaccination achieves. Generally speaking, targeted vaccine escape will not happen to the virus.

The mutation in Israel is still completely controllable because Israel is one of the most commonly vaccinated with the Biotech vaccine. Although various virus strains escaped from the vaccine in the world and the region can be found, there was no runaway outbreak in Israel.

From the clinical data, today's mutation is still under the control of the vaccine. Recently, some protein vaccines have come out. The protection rate of the South African strain has been reduced to 51% and the protection rate of the AstraZeneca vaccine has also declined. So today, as a whole, due to the mutation of virus strains, the protection rate of some vaccines will decline to a certain extent.

For the fact that a vaccine to British strain can be reduced to 70%, many people are also very concerned about the protection rate of inactivated vaccines in China. According to the data recently obtained in the United Arab Emirates, Brazil and other countries, we find that the efficacy of Chinese inactivated vaccines can still reach more than 78% among the local epidemic strains.

From this point of view, although the evolution and mutation of the virus is a normal state, there is no complete escape from the vaccine. There may be a certain degree of escape, but it remains in the effective range.

In the future, vaccination now seems complicated to fully reach an immune barrier in any country in the world. That means that without any public health strategy, the vaccine can prevent 85% of the infection under optimistic conditions, and it is still difficult for us to reduce the whole transmission coefficient to below 1. Therefore, it is suggested that non-drug intervention measures can be maintained to a certain extent in various countries in the future. So I think in the future, non-drug intervention is still vital for countries that have not received perfect vaccination and comprehensive coverage.

From the perspective of the coronavirus, we can see the relationship between the diversity of nature and human beings. We constantly break through a balance in nature, and then natural species will appear to induce infectious diseases among human beings. Once there is an infectious disease, we will gradually balance the new species in nature through vaccination or mass immunization. So looking forward, after the global vaccination, I believe the relationship between humans and the virus will be in a very balanced state.

By vaccinating and developing drugs, we will reduce the virus's mortality to a shallow level, and we can have a long-term relationship with the virus. But at this stage, I believe we have to learn how to run faster than the virus. Through vaccination, we can ensure that the virus does not induce mutation and avoid re-outbreak of the epidemic. We should also implement very decisive non-drug measures for the imported epidemic. So in the future, I believe that the struggle between human beings and the coronavirus will become an excellent example of our interaction, mutual relationship, mutual struggle and mutual survival with nature. We believe that this pandemic can be totally under control in the future. Thank you.


The article is made from video conference and has not been verified by Professor Zhang Wenhong

Link to Zhang Wenhong’s speech:

https://v.qq.com/x/page/i3248u3o8jj.html

(More information is available at CBCGDF Media)


Translator/ Lee

Editor: Syying


Chinse original articles: https://mp.weixin.qq.com/s/FDikPD_vxWkSuzB6ZoPV_Q


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