This article comes from WeChat public account: Glacier Thinkshare (ID: icereview) < span class = "text-remarks">, author: Zhang Tian Kan
On March 13, Patrick Valence, the UK ’s chief scientific adviser, further explained that the UK ’s policy against the epidemic is to infect 60% of the population to obtain herd immunity, thereby delaying the peak of the epidemic until summer.
The new crown pneumonia epidemics facing the world are the same, but different countries and regions have different coping strategies.
On March 12, British Prime Minister Boris Johnson announced measures to deal with the new crown pneumonia epidemic, including requiring schools to stop overseas travel, preventing vulnerable people such as the elderly from boarding cruise ships, requiring fever or a persistent cough for more than 4 hours. People carry out self-isolation, etc.
However, the school is still open, and large parties such as sports events and concerts are held as usual.
On March 13, Patrick Valence, the UK ’s chief scientific adviser, further explained that the UK ’s policy against the epidemic is to infect 60% of the population to obtain herd immunity, thereby delaying the peak of the epidemic until summer.
The words of the British Prime Minister and the government’s chief scientific adviser have left many people confused. In the face of the epidemic, people are afraid to avoid it. The government should introduce a strict precautionary policy. But why should the British let the majority of the people actively become infected?
Isn’t this numbness, and grass is killing people? ?
Not only the UK, but also Japan and Sweden have taken similar measures
Actually, although the UK ’s response to new coronary pneumonia is somewhat unique, it is based on scientific evidence, and it is not the only one with no branches.
Any decision needs to be scientifically based. The scientific rationale for this decision in the UK is that new coronary pneumonia is likely to become seasonalFlu-like illness recurs every year. Therefore, gaining immunity from a group of illnesses will be a countermeasure for long-term control of the disease. “The infection rate of 60% is the number that obtains group immunity.”
The purpose of the British government is to protect those who are most affected, “to delay the epidemic peak to summer and then control the epidemic.” At that time, the burden on the British national health system would not be that heavy. “Our goal is to try to reduce the peak, expand the peak, not suppress it completely,” “Since the vast majority of patients have milder symptoms, more people will become immune to this virus after establishing herd immunity, so we can reduce transmission While protecting the most vulnerable groups. ”
▲ Foreign media reported the British government’s initiatives (picture / network)
First of all, the majority of patients with new crown pneumonia are mild, which has been confirmed by the new crown epidemic situation in various countries, which is the basis for the decision of the UK’s anti-epidemic policy.
World Health Organization (WHO) Data show that 80% of confirmed cases of neocoronary pneumonia are mild, common, including no pneumonia or pneumonia Patients; only 13.8% of the patients are severe, and the proportion of asymptomatic infections is unknown.
So, with limited medical resources to treat fewer critically ill patients, good steel is used on the blade. Otherwise, medical resources and health systems will be overwhelmed, and the epidemic will be expanded.
Not just the UK, other countries have adopted similar measures.
On February 25th, the Japanese government announced the latest policy to cope with the new crown pneumonia epidemic. The critically ill patients were admitted to medical treatment, and the mildly ill patients were kept at home. While suppressing the spread of infection, the number of severely ill patients and deaths were minimized. .
On March 12, Sweden decided to stop statistics on confirmed cases of new coronary pneumonia, and the country will no longer test mild and suspected patients. Since notThe new crown may be prevented from spreading in Sweden. The country ’s public health agency said it will use limited resources for high-risk groups such as medical staff and hospitalized patients.
Of course, these countries’ response policies may be dismissed as lazy or the scientific basis is not sufficient. However, there is still a more sufficient scientific basis, that is, immunological imprinting (immunological imprinting) , or immune memory theory.
▲ London Heathrow International Airport (Picture / Internet)
The theory means that if a person has a disease and is infected with new coronavirus pneumonia this time, the body will develop immunity against this disease. In the years to come, if you encounter a new coronavirus infection, The antibodies and immune system in the body will be awakened by immunoblotting, attacking pathogens, protecting people from the same disease, or even if they get the disease again, the symptoms will be much milder and will not cause death.
The scientific basis for people to get flu to gain immunity
Influenza A is a zoonotic disease that people experience and suffer from every year. However, the variability of the flu is also difficult to prevent. Even if the influenza vaccine is given every fall and winter, it is difficult to prevent people from getting flu. The reason is the variability of the influenza virus.
Due to the variability of influenza viruses, influenza vaccines are in a lagging stage, that is, the annual influenza vaccine is only developed based on the virus strain of the previous year and predicting what changes will occur in the coming year, so it cannot completely prevent the flu of that year.
In this case, earlier British researchers first proposed that gaining immunity by naturally influencing the flu is more powerful and more resistant to the flu than the flu vaccine.
▲ Under the prevention and control measures, the different changes of the epidemic situation (picture / network)
In January 1969, when the H3N2 flu first spread in the United States, it killed many people. However, during the second peak of H3N2 flu from June to December 1970, patients in the UK, Europe and Australia plummeted.
This result attracted great attention from professionals. After careful investigation, British researchers found that the H3N2 flu first occurred in Hong Kong, China in mid-July 1968. People who were infected with the H3N2 flu at the time unexpectedly resisted the flu when the flu broke out in 1969 and 1970.
This means that the specific immunity that was naturally acquired after the flu had previously affected the later defense against the same or similar flu.
To verify this mechanism, British researchers conducted experiments in South Wales. Flu antibodies were measured in two groups of people who were continuously vaccinated and volunteers who were not vaccinated. Antibody titration tests are performed around winter each year.
The results show that the natural immunity of wild H3N2 influenza virus (influenza) is more inactivated than inoculation against Hong Kong influenza The immunity obtained by the vaccine is more durable.
According to this situation, researchers believe that the natural immunity is stronger and longer lasting than the artificial immunity. This once again proves a theoretical “primary antigenic damage” in immunology, which refers to the first infection by a wild pathogen (all pathogenic microorganisms) The imprint left on the body’s immune system is much deeper than the imprint left at any time after infection.
Thus, when you are infected with similar pathogens in the future, the deep imprint will quickly wake up the immunitySystemic memory, which produces a large number of antibodies or activates immune cells, effectively destroys pathogens.
The latest scientific research also supports this conclusion
On February 4, 2020, researchers from the University of California, Los Angeles and the University of Arizona published a research article in the journal Public Science Library Etiology, saying that people had the flu in the early stages of life, or they could be prevented. No longer have the same type of flu, or it is very mild.
Researchers obtained records of some patients from the Arizona Department of Health. After research, they found that in the past few decades, two subtypes of influenza virus (H3N2 and H1N1) caused seasonal flu outbreaks.
Most people born between 1918-1957 were first exposed to the H1N1 influenza virus, and middle-aged people born between 1957-1968 were first infected with H2N2, but since 1968, H3N2 has been seasonally flu The main strains, so most young people are first exposed to H3N2.
A surprising result is that if a person is first exposed to the H3N2 virus in their infancy, if they encounter the H3N2 flu again later in life, they are less likely to have a serious hospital stay. Similarly, the person who first encounters H1N1 at an early age will have a stronger resistance when they encounter H1N1 flu again in the years to come.
▲ British man wears full protective clothing to go shopping (picture / online)
Another finding is that even if you encounter H1N1 flu when you are young, you will have some resistance when you encounter H3N2 flu when you grow up, but you will not have the same symptoms as when you had H1N1 flu when you were young. Strong resistanceThe same is true of H3N2 flu.
This conclusion was also put forward in another article published in Science in 2016 (Science) , childhood-influenza flu The virus will enable people to obtain partial protection in the future, and be able to escape the infection of the flu virus. Even those with a relatively distant flu virus, the people who have had the flu have protection.
Thus, the flu viruses that came in contact in the past determine a person’s future response to the flu, whether they are sick, and how serious they are.
What is the worst result? Will the British people agree?
Obviously, the above studies are only for influenza.
It should be noted that if people want to get the flu naturally without the flu vaccine to gain stronger immunity, there are obviously risks, especially for high-risk groups such as the elderly and people with other diseases. So at this stage, researchers are also encouraging people to get vaccinated during the flu season.
There is no clear conclusion as to whether the treatment of neo-pneumocoronary pneumonia can be as effective as the flu. Therefore, the practices of Britain, Japan and Sweden are somewhat risky. The premise and basis of decision-making are based on the current situation, that is, most of the new coronary pneumonia is mild, and only a few severe patients will be life-threatening.
▲ People wearing masks on the streets of the UK (Picture / Internet)
According to statistics from the Chinese Centers for Disease Control and Prevention, the case fatality rate of 60-69 years old is 3.6%; the case fatality rate of 70-79 years old is 8.0%; the case fatality rate of 80 and above is 14.8%.
Under this premise, the United Kingdom believes that most people will not be affected by the new crown virus infection, and they will have stronger immunity. Medical careResources for critically ill patients. This approach certainly takes time and clinical practice to test.
Of course, there are other grounds for Britain ’s response, such as the epidemiological characteristics of new coronary pneumonia. Under current circumstances, strict restrictions on public life should not be imposed immediately.
The British government’s chief scientific adviser, Valance, said, “If you suppress something very strictly, it will rebound when you release it, and it will rebound at the wrong time.”
In addition, according to the reality that most of the infections are mild, the British government is worried that if there are not enough people now infected with the new crown virus, it will reappear this winter, which will cause a serious burden on the British medical system. .
So, if you take this as a bet or adventure, what is the worst case scenario?
Recently, the Chief Medical Officer of England, Chris Witty, said that the worst case may be that about 80% of the entire population of the United Kingdom will be infected with the new crown virus, and about 1% of patients will die.
According to this assumption, the British population is 66 million, and 80% of the people are infected with 52.8 million. About 528,000 of them may die.
This is really a “big bet”!
Of course, this is the worst case scenario. Several other data can draw some comparisons: the number of deaths from flu in the UK in 2014-2018 is around 1-2 million per year. In the United States, at least 10,000 people die from the flu each year, and 61,000 people die from the flu in the 2017-2018 year.
▲ UK Flu Mortality Statistics (Picture / Internet)
Will this “big bet” Britain win? I’m afraid it’s difficult to draw conclusions. But even with scientific evidence, the British government still faces difficulties when it wants to fully implement its ideas.
The question before us is that YingWill the people of China agree? !!
This article comes from WeChat public account: Glacier Thoughtshare (ID: icereview) , author: Zhang Tian Kan