(China Focus Face-to-face) For questions about vaccination, experts in disease control provide authoritative answers
China News Service, Beijing, February 8th, title: Questions about vaccination, experts in disease control give authoritative answers
——Interview with Shao Yiming, a researcher at the Chinese Center for Disease Control and Prevention
Author Peng Danni
The new crown pneumonia epidemic is still raging around the world, and vaccines have become an important means for countries around the world to fight the new crown epidemic.
As of 24:00 on February 3, a total of 31.236 million doses of new crown virus vaccines have been reported to key populations across the country.
Regarding vaccination, safety, and how to achieve herd immunity, Shao Yiming, a researcher at the Chinese Center for Disease Control and Prevention and consultant of the World Health Organization's Vaccine R&D Committee, accepted an exclusive interview with China News Agency "China Focus Face-to-face" to provide authoritative answers.
Excerpts from the interview are as follows:
China News Agency reporter: At present, are the vaccination rates and vaccination rates in my country in line with expectations? What is the level in the world?
Shao Yiming
: China is fast.
It should be said that our country's new crown (pneumonia) vaccine research belongs to the world's first legion. It is the first country to start clinical trials and the first country to enter Phase III clinical trials.
In accordance with the needs of epidemic prevention and control, under the coordination of the vaccine research and development team, the vaccine team of the Joint Prevention and Control Coordination Mechanism of the State Council and the State Food and Drug Administration, in July 2020, my country was the first country to approve vaccines for emergency use.
Our country’s higher-risk groups, front-line prevention and control teams, customs and border defense, and some important jobs, such as terminal staff, personnel related to imported goods, and students studying abroad, have started emergency vaccination from that time. .
It should be said that the country's work arrangements are scientific and sound.
Because unlike many countries in the world, there is not much risk of infection in our country.
In China, in the summer and autumn of last year, most of the daily new local cases were single digits, and very few were double digits.
Now, we have entered the second epidemic season. The global epidemic is growing very fast, with hundreds of thousands or even millions of new cases per day.
In countries with high epidemics, vaccines are urgently needed to curb the growth of the epidemic and protect their high-risk groups. The demand for vaccines is more pressing than ours.
Therefore, we can meet the domestic demand for prevention and treatment by conducting vaccination in an orderly manner in accordance with government arrangements.
Data map: On January 29, at the temporary vaccination spot in Xueyuan Road Street, Haidian District, Beijing, medical staff vaccinated the vaccinated.
Photo by China News Agency reporter Jiang Qiming
China News Service reporter: Some experts infer that 70% of people vaccinated with the new crown vaccine can establish a relatively stable herd immune barrier in China. How should the public understand the concept and meaning of "herd immunity"? How is the 70% ratio calculated?
Shao Yiming
: The immune system evolved through our human body can produce pre-immunity against infectious diseases and then respond to infections or diseases caused by it.
The prevention and control of infectious diseases is the three major interruptions.
One is to control the source of infection, find the source of infection, isolate and control it; the second is to cut off the route of transmission, block it before infecting new susceptible people; the third measure is to protect susceptible people and make them vaccinated There is a certain degree of resistance, and the vaccinated people who can have a certain immune barrier reach a certain proportion of the population, and it is difficult for the virus or germs to spread again.
As for how many people need to be vaccinated to achieve herd immunity or build an immune barrier, it depends on the ability of a virus or bacteria to spread.
You can use a simple formula, 1-1/R0, to calculate the percentage.
R0 is called the basic reproduction number, which refers to how many people can be infected by a person with a virus.
The R0 of the new coronavirus is estimated to be high or low, and the average is about 3. That is, one person can pass about three people, and the calculation (the required vaccination rate for herd immunity) is 66%.
At present, the protection rate of the inactivated COVID-19 vaccines on the market is about 70% to 80% on average.
There may be some loss during transportation.
Therefore, it is safer, 80% of the population is vaccinated, which can achieve the herd immunity barrier.
China News Agency reporter: How long do you think it will take China to reach the 70% to 80% vaccination rate target?
Shao Yiming: Actually it is affected by several scientific and technological factors.
In the past year, the scientific community has continuously reported the secondary infection of the new coronavirus, indicating that this virus is in some people (this ratio is still difficult to calculate) and the immunity is not particularly durable.
In other words, the establishment of herd immunity is restricted by how high the protection rate of the first batch of vaccines is and how long the immunity can be maintained after vaccination.
Shao Yiming, a researcher at the Chinese Center for Disease Control and Prevention and a consultant to the World Health Organization's Vaccine R&D Committee, accepted an exclusive interview with China News Agency "Focus on China".
Photo by China News Agency reporter Jiang Qiming
China News Agency reporter: Regarding vaccines (vaccinations), what kind of information should be conveyed to the public in this regard?
Shao Yiming
: Our citizens' response to scientific and government epidemic prevention (measures) is one of the best countries in the world.
There may be some people who think that China's vaccine protection rate is relatively large, and some people think that we use more traditional technology, inactivated vaccines. How safe is it?
From a scientific point of view, it is precisely these two factors that do not need to be worried.
In medicine, what kind of drugs and vaccines are the safest must pass clinical trials.
The more people who test and the longer the test, the more proof of safety.
In this sense, the inactivation (technology) used in vaccines in our country has been used for hundreds of years, and the vaccine of this technical route has been used by all mankind, and it should be said to be reliable.
Data map: On February 2, people lined up at the gate of a vaccination spot in Chaoyang District, Beijing.
Photo by China News Agency reporter Yang Kejia
China News Agency reporter: For the elderly, a susceptible high-risk group, the domestic new crown vaccine has not yet been opened to them. Approximately how long will China's new crown vaccine cover this group?
Shao Yiming
: When we generally do clinical trials of new drugs and vaccines, we start with young and middle-aged people because they have a strong tolerance for new drugs.
Regardless of whether it is the first or second phase, our vaccine class is required to follow this principle when discussing strategies and when reviewing national new drugs.
As long as it is safe to pass the first stage of the young and middle-aged (experiment), it will expand to children and the elderly at both ends of the age. The sample size is exactly the same in each group.
Judging from the (New Coronary Vaccine) Phase I and II clinical trials, the final results of the three age groups are safe, and the side effects of the elderly group are lower.
We have also noticed that the domestically produced new crown vaccine has been approved for use in many countries and is used by people of all age groups.
This shows that the safety of the vaccine is guaranteed.
In fact, our country has very strict management of places where the elderly are concentrated, such as some elderly service institutions such as nursing homes.
Therefore, there are very few infections in places where the elderly are concentrated. In this sense, the elderly in our country are not at a high risk. They are actually at lower risk than the general population.
Reporter from China News Service: Can you tell me what steps a vaccine will go through after it is produced from a factory and will be distributed to various provinces? How long does the transportation and distribution process usually take? For example, take Beijing as an example. This distribution process What is it like?
Shao Yiming
: Our country has a very good public health system. There are
disease control
centers at all levels from the central to the provinces, cities and counties.
There is also a maternal and child health care system, as well as some specialized diseases, such as tuberculosis and skin disease prevention and treatment systems, all of which can be vaccinated.
In recent years, the health care reform has strengthened the grassroots, and many public health service centers have been built in the community, all of which can be vaccinated.
The vaccine has a special traceability code, and the entire process of transportation, distribution, and use is strictly monitored, so people can rest assured that they can get the vaccine nearby.
Shao Yiming, a researcher at the Chinese Center for Disease Control and Prevention and a consultant to the World Health Organization's Vaccine R&D Committee, accepted an exclusive interview with China News Agency "Focus on China".
Photo by China News Agency reporter Jiang Qiming
China News Agency reporter: Do you have any impression of the most extensive vaccination in China in the past? What experience can be used in this new crown vaccination?
Shao Yiming
: For example, the measles vaccine we used in the past was very good, and the smallpox vaccine that we used most strongly in the past.
At that time, there was a high degree of consensus in the world. Under the promotion of the World Health Organization, after about ten to twenty years of hard work, smallpox was eliminated in 1979.
Human activities inadvertently caused many species to become extinct, but we only extinct one species, that is, variola virus.
Because the death rate caused by this disease to humans is too high, everyone is afraid, and a high degree of consensus can be generated.
We still have to do a good job in science education.
For example, the integration of our national health work with mass movements is actually to promote to the public so that everyone has the concept of public health.
Because the prevention and treatment of infectious diseases only requires everyone to participate, and everyone is safe, in order to ensure personal safety.
China News Service reporter: What do you think will be the situation of the global epidemic in this autumn and winter?
Shao Yiming
: The new crown epidemic is now in the second annual epidemic season of the respiratory disease pandemic.
Just like the Spanish flu in 1918, the peak (outbreak) was in early 1919.
The current situation is the same, but I think this momentum will be quickly curbed.
Because many countries are now aware that the prevention and control in the past has not been done in place and thorough as in China, and they are now improving, such as the "100-day plan" of the Biden administration in the United States, and (wearing) masks is no longer a controversial issue. problem.
Together with these measures and the large-scale vaccination, the global situation will turn for the better.
At that time, the upward trend of the epidemic should be weakened by at least 50%.
By the summer of this year, when it is not conducive to the spread of respiratory diseases, the northern hemisphere will stabilize, and the world will be able to respond more securely to the epidemic prevention and control this winter and next spring.
Shao Yiming, a researcher at the Chinese Center for Disease Control and Prevention and a consultant to the World Health Organization's Vaccine R&D Committee, accepted an exclusive interview with China News Agency "Focus on China".
Photo by China News Agency reporter Jiang Qiming
China News Agency reporter: About virus mutation. In your previous interview, you mentioned that inactivation and mRNA vaccines are the faster way to deal with virus mutations. For inactivation, you only need to replace the seed virus in the fermenter of this virus. You said it takes about two months. Compared with other technical routes, why is inactivation more advantageous?
Shao Yiming
: Because virus strain screening does not take a long time, for example, a rough result can be obtained in two weeks, and the entire production cycle is about 40 days.
The same is true for the mRNA vaccine, it is actually synthesized on the machine, (equivalent to) giving it a new blueprint, the machine can complete this task.
For other routes, such as recombinant protein and viral vector vaccines, the process steps are very complicated, and it takes dozens of steps to complete this task.
This is why mRNA and inactivated vaccines were first marketed.
Data map: On January 8, in Shenyang, Liaoning, the staff showed the new coronavirus vaccine to be vaccinated.
Photo by China News Agency reporter Yu Haiyang
China News Agency reporter: What do you think of the impact of virus mutation on vaccines?
Shao Yiming
: The direct and fastest test is to test the serum from the vaccine in vitro to test its neutralizing ability.
We have seen that the ability of antibodies to neutralize the mutant strains found in the UK is better, while the strains found in South Africa have dropped a lot.
Of course, this data is not equal to the protection of the vaccine in the body.
The response (method) depends on what the dominant strain is circulating in a region.
Existing vaccines have good protection against early epidemic strains in Wuhan, including Italy, France, and Germany.
(If the prevailing local strains mutate) I think we can consider using a two-valent vaccine: one is for the early epidemic strain, the other is the new epidemic strain that has become more important locally.
I think the development of the new crown vaccine will move towards a multivalent vaccine like the flu vaccine in the future.
The flu vaccine uses a quadrivalent vaccine every year, that is, different types of mutant strains are put together for injection.
We don’t have to panic. Science is constantly studying, data is accumulating, and vaccines are not updated. When to update, the government health department will make scientific judgments based on the data.
(Finish)