SCIO press conference on COVID-19 origin tracing
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E-mail China.org.cn, July 25, 2021
Xinhua News Agency:
Since the outbreak of the pandemic, scientific research has played a very important role. Could you talk about the work of the Ministry of Science and Technology in terms of the scientific research on origins of COVID-19? What achievements have been made? Thank you.
Xu Nanping:
Thank you for your question. There are a lot of journalists today, and everyone looks very serious. It shows that everyone recognizes the importance of the origin tracing of COVID-19. We should realize that origin tracing is substantially a scientific matter, so scientific research has played a crucial role in searching for origins of the virus. The Chinese government attaches great importance to the scientific research on the origin tracing of the virus. After the outbreak, China made five priorities for scientific research, and origin tracing of the virus is one of the priorities which has been considered as very important. The Chinese government called on the scientific research community to follow the principle of "open, transparent and responsible" and put the utmost effort to find out "where the virus came from." Responding to this call, the Ministry of Science and Technology has organized research groups from the Chinese Academy of Sciences, the Chinese Academy of Medical Sciences, the Chinese Center for Disease Control and Prevention, and universities to carry out scientific research on the origin tracing of the virus on a number of priority areas, including animals, humans, molecules and the environment. Some progress has been achieved.
I'd like to name some examples. I think everyone is concerned about the first one. After human-to-human transmission was detected, we wondered where the virus came from; whether it was the animals around us which might have transmitted the virus to humans; or whether it could spread from people to animals. All these regard tracing animal origins. We conducted nationwide viral tests over wild animals, poultry and livestock in 31 provinces, municipals and autonomous regions soon after the epidemic broke out. The tests covered dozens of species, such as pigs, cattle, sheep, chickens, ducks, geese, pigeons, turkeys, wild rabbits and wild boars. We tested more than 80,000 samples over a short period of time, and no COVID-19 antibodies or positive nucleic acid test results were detected. After that, we further conducted COVID-19 challenge trials on animals around us in the lab, and classified them into groups according to their susceptibility to COVID-19 infection, such as highly susceptible, not susceptible or resistant. By doing so, we further understood the situation, and it was also helpful for us to determine the priorities in terms of tracing animal origins.
Second, in order to define the origin of the virus, bat was one of the animals we focused on. In the wake of the COVID-19 outbreak, we organized several groups to conduct research on the coronavirus carried by bats to identify its similarity with SARS-CoV-2. As several experts said just now, bat coronavirus RaTG13 has a 96.2% genome homology with SARS-CoV-2. Yet further research found it shows only 89.3% amino acid homology in the receptor-binding domain (RBD), meaning that its infectiousness is to some extent very low. Our further experiments showed that the infectiousness of RaTG13 differs greatly from SARS-CoV-2 when infecting different species. As such, experts have concluded based on a comprehensive study and judgement that RaTG13 has a remote evolutionary relationship with SARS-CoV-2.
Apart from bats, researchers also found other animals carry SARS-CoV-2-related coronavirus. For instance, scientists detected multiple strains of coronavirus in smuggled pangolins seized by customs. Among them, the highest genome homology with SARS-CoV-2 is 92.4%, lower than RaTG13, but one strain of the pangolin coronavirus shows 96.9% amino acid homology with SARS-CoV-2, higher than RaTG13's 89.3%. Through those studies, scientists concluded that pangolin coronavirus may have played a role in the evolution of SARS-CoV-2.
Our research groups have done lots of other work such as molecular tracing. The origin-tracing work has made solid progress due to joint efforts with overseas scientists. By July 19, Chinese research groups and their overseas counterparts from the U.S., the U.K. and other countries had jointly published 225 articles related to tracing origins of the COVID-19 virus, and Chinese research groups had published 352 articles. That shows our origin-tracing work is highly international. During this period, Chinese and U.S. medical scientists held six dialogues via video link on prevention and control of COVID-19. On top of that, we have beefed up efforts on data and information sharing regarding scientific research, and established the 2019 Novel Coronavirus Resource database for global sharing under the China National Center for Bioinformation. By July 19, the database had garnered and shared more than 2.53 million collections of worldwide SARS-CoV-2 genome sequences, and offered access to almost 300,000 users from 177 countries and regions.
More than one year of effort has made us realize that tracing origins of the virus is a scientific question full of uncertainties, so there is a long and arduous way to go. At the same time, we should realize that origin-tracing work is very important, and we should give a good answer to the serious and fundamental question about where the virus comes from. With responsibilities falling on us and difficulties lying ahead, we must firm up our confidence and adopt a science-based approach. Only by basing the origin-tracing work on scientific attitudes, scientific methods and scientific facts can we uncover the truth. Thank you.
