The golden sentence:
The Omicron strain is highly infectious, and it is stronger than "take all". That is, no matter whether you are vaccinated or not, the Omicron strain can be infected.
Vaccination is very limited in preventing (Omicron strain) infection, although it can prevent severe disease. It breaks through the protective effect of vaccines.
It is necessary to further adjust and improve the epidemic prevention strategy, but it is unclear when and how to adjust it, because there is no good way to "conquer the enemy with one move".
Influenza is an upper respiratory disease, which mainly infects the throat; coronavirus is a lower respiratory disease, which mainly infects the lungs, but may also infect other organs of the human body.
The case fatality rate of infection with the new coronavirus, even the lower case fatality rate of the Omicron strain, is higher than that of the flu.
Since the local confirmed cases of new coronary pneumonia appeared in Manzhouli, Inner Mongolia at the end of November 2021, from the northeast to the northwest, east China, and then to the north and central China, a new wave of new epidemics has formed in China that lasted for nearly two months. Most of the time, the number of confirmed cases in a single day exceeded 100. example.
Among confirmed cases in Tianjin and other places, a more contagious and mutated strain of the new coronavirus Omicron has also emerged.
The epidemic situation in countries such as the United States, the United Kingdom and France is more severe.
Data from the World Health Organization shows that on December 23, 2021, the number of new confirmed cases of new coronary pneumonia in the UK exceeded 100,000, breaking the record of 68,000 confirmed cases in a single day set in January 2021; after entering 2022, continue to It reached a new high, reaching a peak of 218,300 new confirmed cases in a single day on January 5.
Also breaking the record is the United States.
On January 12, the number of newly confirmed cases in the United States exceeded 1 million, reaching 1.3367 million, setting a new record for new confirmed cases in the country in a single day since the outbreak of the epidemic.
Due to the sharp increase in the number of confirmed cases in these countries, the number of new confirmed cases in the world has also formed a new peak every day, with more than 3 million new confirmed cases in a single day.
Wu Zunyou, chief epidemiologist at the Chinese Center for Disease Control and Prevention, told the Beijing News Beijing Think Tank that European and American countries did not take effective prevention and control measures when facing the Omicron strain, which further led to the global spread.
This not only made the epidemic situation in its own country more severe, but also caused the epidemic to spread further to more countries.
China's current overseas imported cases mainly come from European and American countries, especially the United States.
Why has the domestic and international new crown epidemic situation become so severe this winter?
Why did the Omicron strain, known as the terminator of the new coronavirus by European and American countries, lead to a more severe epidemic situation?
With the vaccination rate of more and more countries in the world reaching 70% to 80%, can we take the lead in opening the door to return to normal?
The Beijing Think Tank interviewed Wu Zunyou for this.
Basically similar to the 2020 winter epidemic
Xinjing Think Tank: Since the end of November 2021, from Manzhouli, Inner Mongolia, to Xi'an, Shaanxi, and then to Tianjin, epidemics have occurred one place after another.
Why is there such a wave of epidemics that lasts for so long and is not in the same place?
Wu Zunyou: It should be said that this wave of epidemics is very similar to the situation in the winter of 2020.
There are several factors. The first is that respiratory infectious diseases are more likely to spread after the weather is cold.
Some of this wave of epidemics occurred independently. For example, the epidemics in Shenzhen, Guangdong, and Yunnan were independently imported from abroad and led to local distribution; some were related, and the overflow of cases in one place led to the formation of local epidemics in the next place, such as the overflow from Inner Mongolia and Tianjin (Tianjin's Case spillover led to the formation of a new crown epidemic in Anyang, Henan).
Why are epidemics easy to form in winter?
It is affected by two factors. First, the global epidemic situation is more severe in winter, resulting in the introduction of overseas epidemics into my country.
The current epidemic situation in my country is basically caused by imported cases leading to local transmission. If there are more overseas cases, it will be more difficult and risky to prevent imported cases.
Second, people tend to gather indoors with poor ventilation in winter, which makes it easy to spread respiratory diseases.
Secondly, for China, the overall situation of epidemic prevention and control is relatively good, and everyone has been lax, resulting in the implementation of normalized prevention and control measures, especially the implementation of personal protection measures.
In particular, some infected people, because of their low vigilance after they have symptoms, continue to move.
This in turn results in family or community (friends, neighbors) transmission.
Thirdly, although the domestic vaccination rate is already high, some vaccinated people are infected with mild symptoms or no symptoms at all, resulting in occult infection.
By the time the re-infected person went to the hospital for a serious illness, he had already been infected.
In addition, some cities are caused by insufficient prevention and control capabilities and inadequate command implementation.
Just like the epidemic that occurred in a northern province in January 2021, we went directly to the front-line command after we went.
Although it has been two years of the epidemic, it is easy to see that other people (prevention and control work) do it, but some cities have not experienced it and have not accumulated corresponding anti-epidemic experience.
Xinjing Think Tank: The domestic epidemic is still dominated by Delta, which is not the same as the international situation.
As far as this epidemic is concerned, do you think it has brought any inspiration to our prevention and control work?
Wu Zunyou: In the face of various mutations of the new crown, the current normalized prevention and control measures are still effective.
The biggest problem facing now is that the constantly mutating strains, like the Omicron strain, have milder symptoms after infection, which is a good thing for individuals, but it is more difficult for groups to prevent and control; There are many breakthrough cases of the Mikron strain, which makes the vaccine prevention and control strategy need to be further adjusted.
The only way to do this at the moment is to get a booster shot.
Omicron strain breaks through vaccine protection efficacy
Beijing Think Tank: Since mid-to-late December 2021, the number of newly confirmed cases in many countries in Europe and the United States, as well as in South Africa, has almost broken records every day.
What do you think is the reason?
Wu Zunyou: The most important reason is that they were not able to fight the epidemic. When the Omicron strain caused the spread, the United States and the United Kingdom did not take any effective defense measures. shortened.
It can be said that they are allowing the Omicron strain to spread.
This makes the epidemic in its own country even more severe.
At the same time, it has also had a greater impact on the epidemic situation in countries around the world.
Because there are no restrictions on outbound travel from the US, UK, etc.
More than 1 million cases are diagnosed in the United States a day, which in fact greatly increases the risk of spreading the epidemic around the world.
The imported cases in China are mainly from the United States, including the cases of the Omicron strain, mainly from the United States.
Although South Africa is the first country in which the Omicron strain was discovered, the United States, the United Kingdom, etc. have really played a core or amplifier role in the worldwide spread (Omicron strain).
Beijing think tank: Tianjin has also seen cases of infection due to vaccination.
Compared with Delta, does it mean that the Omicron strain is more powerful?
Wu Zunyou: Our current understanding of the Omicron strain is still very limited, but we do have a new understanding of it now.
Our original belief that it was highly contagious was based on laboratory studies, with very limited real-world data.
Now we realize that the Omicron strain is highly contagious and "takes all".
What is all-you-can-eat?
That is, no matter whether you are vaccinated or not, the Omicron strain can be infected.
For example, more than 1 million cases were diagnosed in the United States a day, 100,000 to 200,000 cases were diagnosed in the United Kingdom, and 200,000 or 300,000 cases were diagnosed in France a day, all of which were affected by the Omicron strain.
For example, of the 107 cases announced in Tianjin on January 12, 2022, only 1 case has not been vaccinated, the rest have been vaccinated, and even 32 cases have completed booster vaccination.
That said, vaccination is very limited in preventing (Omicron strain) infection, although it can prevent severe disease.
This infectivity enhancement is not the same as the infectivity enhancement we usually talk about. It breaks through the protective effect of vaccines.
The new coronavirus can't be like the flu
Xinjing Think Tank: Although the infectivity of the Omicron strain has increased, is it possible that the harm caused by it is not so serious?
Wu Zunyou: It depends on how you say it.
Compare with the new coronavirus, SARS in 2003 and Middle East Respiratory Syndrome (MERS), which are both coronaviruses.
Among the three viruses, the case fatality rate (that is, the death rate per 100 infected people) is the highest in the Middle East Respiratory Syndrome, which is about 34%, SARS is about 10%, and the new coronavirus is about 2% (calculated according to the data released by the WHO, about 1.7%).
However, the social impact and economic damage caused by the new crown virus is the largest, and it is also responsible for the most deaths.
why?
Because of the large base of new coronavirus cases, although the fatality rate is relatively low, the absolute number of deaths will be correspondingly high.
In the same way, the Omicron strain has caused more infections due to its insidious transmission. Although the fatality rate is not high, the absolute number of deaths will still be larger.
Taking the United States as an example, the number of confirmed cases in one day was 50,000 or 60,000, but now it is more than 1 million at most, and the base has expanded by one or two times.
This may impact the medical system. If the medical system is overwhelmed and more patients are not treated in time, some mild illnesses may turn into severe illnesses, severe illnesses into critical illnesses, and eventually death.
Therefore, if the base of infection is larger, the absolute number of deaths will be correspondingly larger.
Beijing think tank: Some virologists believe that the Omicron strain is the terminator of the new coronavirus, and the symptoms are mild and the harm is not so great.
Can it be understood that the new coronavirus may become the same as the flu under the influence of the Omicron strain?
Wu Zunyou: The possibility is very small.
Because influenza is an upper respiratory disease, it mainly infects the throat area; coronavirus is a lower respiratory disease, mainly infecting the lungs, and may also infect other human organs.
Different parts of the virus infection have different symptoms. Lung infection is easy to cause pneumonia, while upper respiratory tract infection rarely causes pneumonia.
The case fatality rate of infection with the new coronavirus, even the lower case fatality rate of the Omicron strain, is higher than that of the flu.
In addition, from the perspective of immunity, the protective effect of the flu vaccine is longer than that of the new crown vaccine. The protective effect of the flu vaccine can be maintained for one year, and the new crown vaccine is only 3-6 months.
Therefore, it is difficult to treat the new crown as the flu.
Beijing Think Tank: Some scholars in European and American countries believe that after the spring of 2022, epidemic control may be released.
What do you think about this?
Wu Zunyou: This possibility is relatively high. For European and American countries, opening up or not opening up has little impact on the epidemic situation in their own countries.
After the European and American countries are fully liberalized, the pressure on China will be relatively large.
How China responds to this change requires further research.
Epidemic prevention cannot be limited to biological prevention and control
Beijing Think Tank: In addition to daily protection, vaccines are an effective measure.
Globally, China has one of the highest vaccination rates (over 80%).
At the 2021 Beijing Think Tank Spring Summit, you said, "Whoever increases the vaccination rate to reach the herd immunity rate first will be the first to open the country."
Do you think we can open the door in 2022?
Wu Zunyou: This issue has become complicated now.
It turned out that we judged based on historical experience that as long as the vaccination rate reaches a certain critical value, herd immunity can be formed. Even if a case is introduced, it will not cause an epidemic, so that the country can be opened.
This is based on historical experience and our understanding of medical biology.
But after the emergence of the Omicron strain, our cognition has been refreshed.
In particular, the epidemics in the United States and the United Kingdom, as well as the recent epidemic in Tianjin in my country, all show that our current vaccines cannot withstand the infection of the Omicron strain.
The effectiveness of the vaccine also lies in reducing symptoms after infection and reducing deaths, and the effect of preventing and controlling the spread of the epidemic may not be as good as we originally thought.
For European and American countries, because of their higher awareness and tolerance of the epidemic, I said before that "whoever has the highest vaccination rate can open the country first" is still valid.
For China, it's hard to tell right now.
Because China's current policy is different from that of most countries in the world.
Therefore, after a certain level of vaccination, whether the country's door can be opened, when and how to open the country's door still need further observation and analysis.
Beijing Think Tank: The new crown virus has been raging for more than two years. Do you think our epidemic prevention strategy needs to be adjusted in time?
Wu Zunyou: It is necessary to further adjust and improve, but when and how to adjust, it is unclear now, because there is no good method for "one move to defeat the enemy".
The so-called "one-trick attack" means that, for example, the new crown epidemic can be brought under control with vaccines or drugs.
If there is such a measure, the superior leadership will also be easy to adopt.
At present, the prevention and control effect can only be achieved by taking comprehensive measures, and neither single measures nor "1+2" measures can completely control the epidemic.
Xinjing Think Tank: In 2022, some foreign researchers claimed to have discovered a recombinant new coronavirus strain of Delta and Omicron, and named it "Delta Coron".
What does this indicate about the characteristics of the new coronavirus?
Wu Zunyou: Actually, virology experts and the World Health Organization have clarified this matter. This is because the laboratory was contaminated with an erroneous gene sequencing result.
But it is indeed possible that more mutant strains will appear in the future.
It is also possible that this new mutant strain has the mutant properties of Omicron and Delta.
This tells us that people are accustomed to using simple biological methods to deal with the new crown virus, thinking that they will be fine after vaccination, or that they will be fine once they take medicine.
In fact, we still have to take social prevention and control or public health protection measures, which will be more effective when combined with biological prevention and control.
Why do you say that?
It is not difficult to find out that China's medical capacity and level are not as good as those of the United Kingdom and the United States, but the effect of China's new crown epidemic prevention and control is far better than theirs.
Text | Xiao Longping, an interviewer with Beijing Think Tank