Southern Metropolis Daily:
We know that some experts say COVID-19 is a self-limiting disease. Does that mean the patients with mild symptoms can stay at home and take drugs by themselves? How should we view a self-limiting disease? Thanks.
Wang Fusheng:
A self-limiting disease is an academic term. It means that infected human body will show symptoms of fever, coughing and a running nose. These symptoms may go away without treatment and will not cause permanent damage to the human body, or develop into chronic disease. For example, when people catch a cold, they need to take more rest, increase their liquid intake, and ensure sufficient nutrition. Without any special treatment, they could recover in about a week.
There are normally three stages for a self-limiting disease, namely incubation, progression and convalescence. In the incubation period, the virus enters the human body and replicates itself, but there are no clinical symptoms. In the progression stage, the immune system and the virus confront each other, which will cause a series of clinical symptoms, such as inflammation of the air passage. In the convalescence stage, the immune system defeats the virus, and patient will recover. Of course, a self-limiting disease doesn't mean there is no need for treatment.
In terms of COVID-19, the patients with mild and regular symptoms occupy 80% of the total clinical cases. Such patients with a better immune system can recover after a good rest and maintaining a positive mood. Even for patients with severe symptoms, with timely and proper treatment, such as taking drugs and inhaling oxygen, their immune system can also be enhanced. And the progression period will be shortened. Normally there will be no sequela, so there is no need for panic.
However, for elderly patients or those with underlying conditions, we need to pay more attention. If not, even the common cold may cause damage to their organs and bodies, and even threaten their lives. So, for COVID-19 patients with a weak immune system, we should provide extra care. They need to rest in bed as much as possible and get sufficient nutrition. Most importantly, they shouldn't be afraid of the virus and keep faith and a good mood in treatment.
It needs to be stressed that COVID-19 is highly infectious, no matter whether the patient has mild or severe symptoms, we must take the measures of quarantine and avoid contact with others as much as possible, in a bid to curb the spread of the virus. Thanks.
Macao Daily News:
According to media reports, many medical institutions from China and abroad are carrying out vaccine developments. So, my question is, what is the latest progress of vaccine development in China? Thank you.
Zeng Yixin:
Thanks for your interest in vaccine development. A vaccine is one of the most effective means for epidemic prevention. As we all know, several epidemic diseases, such as smallpox, polio and rabies have all been eliminated or prevented because of vaccines. In 1979, we declared smallpox a thing of the past. And in 2000, we declared victory against polio. These are all due to vaccine development. But the development of vaccine is like the development of new drugs. It takes a long time and they must pass through a succession of procedures. This was introduced already by Mr. Xu and Mr. Chen. First, we need to design and identify the active ingredients for vaccine. For example, we need the suitable virus strain to be the candidate of the vaccine. Not all of the strings can be suitable, and sometimes we need to find the key protein or genetic sequence in the virus. Then, we move on to the establishment of a manufacturing process and the management of quality control, which also need to undergo a host of experiments, including the evaluation of effectiveness and safety by using animals, in a bid to gain sufficient data to support the application for clinical trial. So, it is a relatively complex procedure. In addition, we are dealing with a new virus. Our knowledge about it is still limited, and that's why there are still uncertainties in the process of vaccine development.
China has made great progress in vaccine research and development, and possesses a group of high-level R&D teams. With the advantages of the country's whole-nation system, we have coordinated efforts to form various vaccine research and development teams. All these teams, with strong sense of mission and responsibility are giving full play to their respective advantages, working in unity and cooperation day and night to speed up their work and achieve success. On the premise of respecting science and ensuring safety, they strive to minimize the research and development time to put vaccines into use as soon as possible.
Now I would like to introduce the latest developments of vaccine research and development. Now, five technical solutions are being developed simultaneously. Please look at the screen. On the left is a schematic of the coronavirus, on the right is a diagram of the five technical solutions for vaccine R&D, and the top one is the inactivated vaccine. The first solution is to inactivate the novel coronavirus after it is produced. The inactivated vaccine can be used for clinical trials after full evaluation of its safety and efficacy. The second technical solution is a genetic engineering vaccine. We mass-produce the protein S, which is the most likely antigenic protein of the novel coronavirus, and then inject the protein into the body to produce antibodies, which may reduce risks of a novel coronavirus infection. The third technical solution is to use adenovirus as a vector. Adenovirus is a modified virus and it is used in replicating the protein of the novel coronavirus, namely the protein S. Adenovirus can infect our respiratory tract, where it replicates the protein S of the novel coronavirus. Then, the protein S can stimulate the production of antibodies to reduce the infection risk. The fourth technical solution relates to nucleic acid vaccines including mRNA vaccine and DNA vaccine. These two vaccines involve injecting nucleic acid including some carriers or nucleic acid wrapped with nanoparticles into the body. There, it replicate the protein of the novel coronavirus. The protein then stimulates the body to produce antibodies thus forming resistance to the virus. The fifth technical solution is to use attenuated influenza virus vaccine as a carrier. We already have an approved attenuated influenza vaccine. We are trying to add the protein of the novel coronavirus into the vaccine. If this solution works well, a vaccine that can prevent both novel coronavirus infection and influenza will be developed. The vaccine is of great clinical significance during such a flu season. Now the five technical solutions are being accelerated simultaneously.
Some projects have entered the phase of animal testing. To give you a visual metaphor, if the R&D of vaccines is just like erecting a building, now the groundwork has been laid and the main part has reached ground level. We are now building as fast as we can, and will then move into the phase of decoration. Our target is to initiate emergency use, procedures for emergency review and approval of vaccines in accordance with the country's relevant laws if the outbreak requires this approach. Under the premise of ensuring safe and effective access, some vaccines are expected to enter the phase of clinical trials as soon as in April or May. We also have been striving for emergency access to vaccines under certain conditions. This is our basic analysis and judgment on the vaccine work. Thank you.
