Zhang Wenhong on International War Epidemic: Is Herd Immunity Reliable? China continues to stand up

Home Health Zhang Wenhong on International War Epidemic: Is Herd Immunity Reliable? China continues to stand up

Original Title: Zhang Wenhong on the International War Epidemic ②: Is Herd Immune Reliable? China continues to stand by and wait

for the epidemic of the new coronavirus pneumonia in Wuhan in recent days. The bombing of information on social media has affected the hearts of the people across the country. To help you understand the dynamic changes of the epidemic, the WeChat public account “Hushan Infection” of Huashan Hospital’s Infection Department affiliated to Fudan University will continue to update the relevant data of the epidemic, and experts such as Zhang Wenhong and Wang Xinyu from the Department of Infectious Diseases of Huashan Hospital will be invited to comment on the trends, hot issues and issues of the epidemic. Relevant precautions, specifically for Q & A interpretation.

Since the outbreak in Wuhan, Zhang Wenhong and Wang Xinyu have been following up. They have written several articles in “Huashan Infection”. Their text is both professional and rigorous and easy to understand. The surging news is authorized to be forwarded. We hope that this This group of articles is helpful for readers to look at the epidemic more rationally and do a better job of self-protection.

This week is the most turbulent week since the beginning of the world’s anti-epidemic-on

March 11, after the World Health Organization (WHO) officially announced that the new coronavirus entered a global pandemic, an outbreak occurred in Europe and became a worldwide epidemic center.

15 at 8 am The global epidemicas of March as of March 15: The

number of U.S. cases has increased, and whether the early disease control of the United States has been questioned by the House of Representatives in time. Trump ’s anti-epidemic strategy has become the center of public opinion;

The British Prime Minister announced the abandonment of the active anti-epidemic strategy and for the first time threw out herd immunization strategies; the

German Chancellor announced that the German infection rate may eventually reach 60%, but Germany has adopted a positive situation to prepare for the famine;

France: there is not much determination and it is mixed in the United Kingdom and Between Germany, “not too good, not too bad” (the original communication between the author and the French national experts in disease resistance);

Italy: continue to be on the verge of collapse, China and the rest of the world launched assistance to fulfill the obligations of the world community;

Traveling to Europe and Americans of Chinese descent: Contradicted by “whether to return home temporarily to avoid the plague or continue to live in the local area while fighting the epidemic”.

We are very, very fortunate to have achieved a phased victory in the initial fight against epidemic through the closure of the city and the response of the whole society.

More than a month has passed, the epidemic prevention process in various countries around the world is like the Olympic long-distance race, which cannot be seen in the first few laps. Later, the epidemic resistance results of various places gradually widened.


  The speeches of heads of states are different. The logic behind the European and American epidemic resistance is that a

US President Trump

announced a national emergency due to the new crown epidemic

Trump announced a national emergency (picture from the White House official website)Trump announced a national emergency State (picture from the White House official website)

——Requires the hospital to activate the emergency plan;

—— Urgently grants the Ministry of Health greater powers, including:

-Can waive the licensing requirements of some healthcare equipment providers;

-Increase test points;

-Expand the coverage of testing reagents ;

– has mobilized the private sector (companies), to join hands in war “plague”, which includes:

– Google website to help develop systems for detecting and monitoring purposes;

– as Wal-Mart insists on not close the door to ensure the supply of daily needs of the people;

– people If testing, it takes several days to produce results;

——I hope to achieve results within 24 hours soon

Comment: Except for the closure of the city and community control, all other measures in the United States are consistent with China’s anti-epidemic strategy, that is, the largest To the extent that US medical resources are open.

  British Prime Minister Boris has

entered the second phase of the epidemic—the “delay” phase.

On March 12, Britain announced its domestic plan for epidemic prevention. At the press conference, British Prime Minister Boris officially announced that the UK has entered the second stage of the epidemic—the “delay”. An article was published after Boris ended the press conference, pointing directly to the nature of the UK’s epidemic prevention strategy. To put it simply, the UK’s epidemic prevention strategy is “not strictly guard against death, tolerate the slow progress of the epidemic, and look forward to the majority of people asymptomatic or only mild symptoms after occult infection, so as to obtain universal immunity in the population to control the epidemic” This is to prevent and control the new coronavirus through herd immunity.

  Italian salamander has

become a typical example of early prevention and control failure. The number of confirmed cases currently exceeds 20,000, and 3,497 new cases have been added within a day. The case fatality rate has reached 6.8%. Medical resources are already running and the state has announced the selective admission of patients.


Chancellor Angela Merkel said, “When the virus has arrived, and the population does not have immunity to the virus, and there are no options such as vaccines or specific drugs, if this situation continues, then the population will Facing a high proportion of infections-experts expect to reach 60-70%. So this is why the development of specific drugs and vaccines is being carried out so intensively. “In fact, Germany is preparing for medical resource reserves throughout Europe. The most abundant country. It is now sufficient to cope with the new severe cases.

Comment: It seems that the speeches of the heads of states are different, but the logic behind the European and American epidemic resistance is actually one-I want to mobilize the largest medical resources that can be mobilized to meet the super infectious diseases that may come. If the country’s medical resources can be effectively organized, I can cope. Like Germany, the current case fatality rate is 0.2%. Less than necessary, we will not take measures to stop society (such as parts of Italy and Wuhan in China). Because once shut down, without a strong government, the country will immediately fall into a greater disaster, and the death toll will far exceed the disease itself. Full research on the disease in early China has given us an understanding of the disease, and the case fatality rate is acceptable. If there is no medical run, the disease can be coped with. But the premise is not to run on medical resources.


  Contribution of Chinese experience to the world

At present, only China has the best results on the surface, because the local cases have been almost completely eliminated (Wuhan will soon be cleared). Academician Zhong Nanshan’s team, Academician Wang Chen and Professor Cao Bin’s team, and Zhang Wenhong’s team in Shanghai have exchanged with the international community several times and introduced China’s experience. Just two days ago, during the dialogue between Chinese and American doctors, the author introduced some strategies for urban prevention and control in Shanghai with a population of 30 million. For example, joint prevention and control cannot be learned abroad, but the hospital’s rapid response and the rapid response to suspected patients Screening and diagnosis, rapid quarantine, and shorter diagnosis and hospitalization are key strategies to reduce outbreaks in hospitals and communities. In fact, the United States has accelerated the training of various community hospitals and also improved the diagnostic capabilities of hospitals (including the supply of reagents and the coverage of costs). Germany is more comprehensive. Both Beijing and Shanghai are international megacities. China ’s experience in megacities is nothing more than restricting population movements and preventing entry, hospitals investing more medical power, screening suspected patients in time, and avoiding medical runs. If medical resources are properly allocated, the fatality rate of the disease can be controlled at about 1-2%, which is an acceptable fatality rate range.


  UK and Germany: One strategy, two versions The

latestEuropean Championship new battle: The

British Prime Minister Boris hopes to adopt a “herd immunity” strategy. German Chancellor Angela Merkel said that 60-70% of the population may be infected. This statement actually caused panic directly. Especially the panic of Chinese of European descent. Because if there are so many people infected, a run of medical resources may occur. Is it going to face great risks?

In fact, the British Prime Minister and the German Chancellor expressed the same meaning. This disease is already a pandemic, and we have no way to adopt China’s prevention and control model. China’s prevention and control model requires a lot of social resources, and we can’t do it. And once the economy stalls, the cost to society may far exceed the disease itself.

In fact, Germany and the United Kingdom did not do nothing. I believe that the current practice in Germany and the United Kingdom is the same as that in the United States. Especially in Germany, the purchase of a large number of ventilator spares has been well received. On the one hand, these European countries are gradually increasing hospitals to make medical reserves for the possible increase in the number of patients with severe illness. On the one hand, I hope that the arrival of the peak of the pandemic can be delayed as much as possible. As long as the peak reached in one month is gradually delayed to reach the peak in 3 months, the incidence decreases with the arrival of summer, and then the number of cases that may occur within one month can be smoothly dispersed to 12 months of the year. It can be dealt with step by step and be reduced to zero. It can be coped with by relying on existing medical resources.

Peak delay and peak reduction after intervention (picture from CDC in the United States)Peak delay and peak reduction after intervention (picture from CDC in the United States)

How can the peak of the disease be reduced? It should be possible by reducing the density of social contact, segregating limited populations, and avoiding super transmission. But Europe and the United States are not China. There is no strong government that can initiate joint prevention and control of the crowd, nor can it implement rapid patient detection and isolation strategies to reduce transmission through 800 outpatient districts on an island country like Singapore. What should I do? Obviously, by telling people about the worst outcome, that is, 60-70% of the population will be infected. In this context, we will announce a series of measures to end large-scale activities, which can be well understood by the public. The living environment in European and American countries is relatively open. There are many independent and independent hospitals. As long as the population reduces large-scale gathering activities, the implementation of home-based work during the peak of the disease, and students taking online classes at home (UK universities have implemented online teaching) can greatly reduce the disease. Spread.

During this period, by greatly increasing the hospital’s response capacity (everything China has done has made a good template), medical runs can be avoided to the greatest extent.

So why is Italy out of control? It is because of the lack of vigilance against the disease at an early stage that a large amount of intra-community transmission occurred in the short term. The out-of-control of the “Buddhism” in Italy against the epidemic is a good lesson for other European countries. It is believed that it will help other countries to accumulate experience in the epidemic.

  No.4 Is

  the so-called “herd immunity” strategy in the UK reliable?

First, let ’s look at what herd immunity is. Herd immunity or community immunity is also called community immunity. That is, when enough people are immune to the pathogen that causes the disease, other non-immunized individuals are protected. be infected. The theory of herd immunity shows that when a large number of individuals in a population are immune to or susceptible to an infectious disease, the infection chain of those infectious diseases transmitted between individuals will be interrupted.

This immunity is usually obtained by having been vaccinated, such as the development and vaccination of the results of smallpox vaccine, which immunized humans or the entire body, and eventually eliminated the infectious disease (speaking of the pox inventor Jenner is British); or This is because the population has been generally exposed to or infected with the virus, such as the flu. But unfortunately, as of now, no vaccine has been successfully used to achieve strong herd immunity in this new crown virus.

  What is herd immunity?

There is also a theoretical basis behind the British government’s adoption of this strategy. The first is epidemiological theory-universal immunity can form a steady state. And a reality is that this new crown epidemic also has the characteristic that most infected patients are asymptomatic or mild, and can be self-limitingly cured without treatment or symptomatic treatment. In addition, the British government was at a press conference. It also reiterated that the mortality rate for the new crown is 1%. Therefore, by releasing the prevention and control of the epidemic, a large number of people will gain immunity after infection, and then focus on medical treatment of critically ill patients in the population. “Death” costs. While controlling the epidemic, we will not sacrifice social vitality and economic development due to strict control measures, and minimize the cost of fighting the epidemic. This is the logic behind the British strategy.

However, such a method of “herd immunity” seems to be feasible in theory. In fact, there are still many uncertain factors about whether it can actually succeed.

From China ’s experience, China has made every effort to protect its citizens from infection, and at the cost of economic sacrifices in prevention and control, has quickly reduced the spread of the virus in the community in a short period of time, and quickly restored social order and strived to restore society. economic development. However, due to the strong determination of the Chinese state and the cooperation of the people, this is not an operation that other countries can copy.

If it is not possible to end the battle in a short time like China (2 months, it happens to be the Spring Festival, creating the best opportunity for a reasonable shutdown of the society). The British government is well aware of the cost of social shutdown, so the strategy of “herd immunity” is at least a theory. The British strategy is based on the fact that most people are asymptomatic or only mildly symptomatic after being infected by the virus, thereby gaining general immunity in the population. However, this strategy is risky for individuals, and some mild patients will suddenly progress to a critical state without warning, and it is extremely difficult to treat critical patients. Under actual circumstances, from Wuhan ’s previous experience and the current epidemic development in Italy and Iran, we know that the biggest risk is an uncontrolled epidemic. Once it spreads rapidly, the number of severe patients will increase. If the hospital’s inadequate response may result in medical resources Run. But if it is well controlled, it can smoothly transition to normalized severe management, like Germany is a model of success.

The strategy of herd immunity is actually not just a scientific issue, it may involve some human and ethical issues, and there may also be huge hidden dangers. With the development of science and technology and civilization in modern society, we hope that more people can get the right to better survival, instead of facing the “survival of the fittest” with the weak power of the individual. When we face an infectious disease with a certain proportion of deaths, and when it is possible to achieve scientific prevention and control, choosing a seemingly fair strategy of herd immunity may have ethical risks.

The “Clinical Ethics” recommendation issued by the Italian Society of Anesthesiology and Intensive Care also suggests that medical personnel should consider “longer life expectancy” as a priority factor in assessments, without necessarily following the “first come, first served” principle To deal with. However, this measure should be implemented only after all relevant parties have made every effort to increase the available resources (in this case, ICU resources), and it is the last resort when medical resources are severely lacking. Therefore, China will definitely not adopt this kind of medical treatment based on “longer life expectancy.” Nearly 50,000 Chinese medical staff rushed to Wuhan, but they were actually unwilling to accept the situation that severe patients could not be treated.

Judging from the fact that countries are frankly accepting the widespread spread of the new crown virus, the subsequent development of the new crown virus epidemic will not be optimistic, and the countries such as the United Kingdom and other Buddhists fighting the epidemic will become pathogen-exporting countries, bringing greater benefits to areas with less developed medical resources Threat.


  China faces the challenge of “crossing the grass twice”

Because most countries in the world adopt the American style, as Roy M Anderson of Imperial College London published a paper in The Lancet said. The goal is to “reduce peak morbidity and mortality and make the epidemic curve more stable.”

In this mode of control, Germany is a model student. Adopt the management model of pandemic influenza, education for all, reduce social activity, and reduce the spread of the epidemic through family self-protection. At the same time, the hospital stepped up preparations for medical resources for critically ill patients. So far, Germany is doing well. However, there are still large uncertainties as to whether other European countries, such as Italy and Spain, can do a good job. Once the run on medical resources occurs, there will be greater uncertainty in society.

China has come to a dark moment. Originally thought that China controlled well, the world would also control simultaneously. East Asian countries such as Singapore, Japan, and South Korea did very well. But now Europe has suddenly become the new epicenter of the epidemic, bringing us huge uncertainty. In the future, China still faces large import risks. According to the current global epidemic situation, it is almost impossible for this epidemic to end this summer. If the epidemic in Italy and Iran continues to evolve in depth, the risk of a new annual outbreak of the new crown will be greater.

China’s next stage is facing huge risks of control and import. The biggest challenge facing Shanghai at present is the large number of overseas flights. The Shanghai expert team said that we have to wait and meet the challenge of “crossing the grass twice”.

At present, the Chinese Health Commission has urgently notified the strengthening of the construction of infectious disease departments across the country, including fever clinics, isolation observation wards, and clinical microbiological testing, which are already in full swing. Relying on China’s strong public hospital network and China’s CDC’s rapid direct reporting system for known infectious diseases, China’s “second pass over grassland” will surely succeed, but it may not end the battle in the short term. People across the country must be mentally prepared to “catch up the epidemic and promote production” until they finally win.

Text: Zhang Wenhong, Ruan Qiaoling Stern

Editor-in-Chief: Fan