Beijing time on April 8 th news, according to foreign media reports, World War I is coming to an end, and a serious flu has swept the world. Spanish influenza * * * infected more than a quarter of the world's population and killed 50 million to 654.38 billion people, making it one of the deadliest epidemics in human history.
19 18 during the Spanish flu, the difference in death toll between Philadelphia and St. Louis reflected the importance of keeping social distance.
1918 In September, when the epidemic was halfway through, many cities in the United States were still planning demonstrations to promote free bonds. In Philadelphia, Pennsylvania, 600 soldiers were infected with the flu virus, but city managers still decided to take the right measures. At the same time, St. Louis, Missouri decided to cancel the March and take other measures to restrict public meetings. A month later, more than 10000 people in Philadelphia died of Spanish flu, while the death toll in St. Louis was less than 700.
This parade is not the only reason for the death toll gap, but the data still shows the importance of these "keeping social distance" measures during the epidemic. Keeping social distance refers to building a barrier consisting of physical distance between two or more people, thus preventing or inhibiting the spread of the virus.
19 18 The analysis of the intervention measures taken in several cities in the United States shows that in those cities where public meetings, theaters, schools and churches are closed early, the death rate during peak hours is much lower than that in other cities.
100 years later, the world has encountered another epidemic, this time caused by a virus called coronavirus pneumonia-19. Today, the global population has exceeded19186 billion. Although coronavirus pneumonia-19 is different from Spanish influenza in many aspects, especially in the main population and mortality, we can still learn an important lesson from the social isolation measures taken in the last influenza. This time, keeping social distance may still be one of the best anti-epidemic measures we can take.
At present, we haven't found a safe and effective vaccine, and we haven't found a specific drug for coronavirus pneumonia-19, so our safest way is to give priority to prevention.
Countries all over the world are taking various measures to force people to keep social distance, so as to slow down the spread of coronavirus pneumonia-19. These measures vary in degree. Some just cancel large gatherings and close public places such as entertainment places, bars and schools. In some places, cities have been completely closed, forcing residents to be isolated from the world.
Although self-isolation is also a form of keeping social distance, there are important differences between the two. The purpose of self-isolation is to prevent infected people or people who have had close contact with patients from spreading the virus to others. Maintaining a wider social distance is to prevent the virus from spreading among people because of the mixing between people.
And this social distance may last for a long time. The latest computer modeling research warns that unless there are vaccines or specific drugs, or radical isolation measures are taken, measures to keep social distance may need to be maintained intermittently until 2022. This is because, although taking such measures can delay the arrival of the epidemic peak, if the virus changes seasonally, the epidemic may still be repeated.
However, there are natural reasons why keeping social distance can be such an important anti-epidemic strategy during this epidemic.
At the beginning of the outbreak, each infected person will infect an average of 2 to 3 people. This infectious ability is called "infectious number" by epidemiologists. In contrast, the number of influenza infections is between 1.06 and 3.4, depending on the type of virus. A study shows that the number of people infected with influenza in Spain is about 1.8. The number of rhinovirus infections ranged from 65438 0.2 to 65438 0.83. However, most estimates of coronavirus pneumonia-19 show that the number of people infected is between 1.4 and 3.9.
The incubation period of coronavirus pneumonia-19 is usually about 5 days, but the longest is 14 days. If you are infected with COVID-19, but still maintain normal social activities, you may infect two or three friends or family members, and each of them may infect two or three people. In this way, in just one month, one case has developed into 244 cases; In less than two months, this number will soar to 59604.
In addition, asymptomatic patients with coronavirus pneumonia-19 can also transmit the virus to others, which undoubtedly further increases the complexity of the problem. According to a study, this asymptomatic infection may account for at most 10% of all cases. It is estimated that 1% to 3% of infected people will not show any symptoms from beginning to end. These people may not know the necessity of self-isolation, but if they can consciously keep their social distance, they can also inadvertently stop the spread of the virus.
There is evidence that people staying at home and keeping a safe distance from others can slow down the spread of the virus and curb this domino effect. The research on the epidemic situation in Wuhan shows that the successful implementation of large-scale control measures has reduced the number of infected people in Wuhan from 2.35 to nearly 1. When the number of infected people reaches 1, the number of cases will not continue to increase.
The epidemic model of China shows that strictly keeping social distance is the key to reduce the number of infected people in Wuhan and Hubei. The study concludes that the sooner the city is closed after the outbreak, the smaller the scale of the epidemic will eventually reach.
One of the main purposes of keeping social distance is to "level the curve", that is, to delay the spread of the virus. The principle is to prolong the spread time of the virus in the population and let the disease develop to the peak in the later stage. The chart shows that if people don't keep social distance, the number of infected people will peak much faster; And if you keep your distance, the epidemic development curve will be much smoother. In this way, at any point in time, the number of people in urgent need of treatment and medical resources will be much less.
What does it mean if it is used in real life? Various countries have taken various epidemic prevention measures. A computer modeling report published in Imperial College London, London on March 16 predicted the spread trend of the virus. After that, Britain also stepped up its epidemic prevention efforts.
Scientists analyzed two methods that Britain and the United States might use to fight the epidemic. The first method is "remission", which only isolates people in danger and forcibly isolates people with symptoms; The second method is "suppression". Everyone needs to take active measures to keep social distance, and people with symptoms and their families need to be isolated at home.
It is found that if no measures are taken, the number of people who died in COVID-19 in Britain will reach 5 1 10,000, and the number in the United States may reach 2.2 million. According to scientists' prediction, the first "mitigation" measure can reduce the medical demand by two thirds and the death toll by half, but it will still lead to hundreds of thousands of deaths, and medical services will be overwhelmed, especially intensive care.
Before the publication of this report, Britain had hoped to achieve "group immunity", that is, to make most people in a society immune through infection or vaccine, so that the number of people who might be infected would be greatly reduced, thus inhibiting the further spread of the virus.
When adopting the group immunization strategy, policy makers are well aware that this practice may promote the spread of the virus, and people's large-scale gathering and other activities are not prohibited, because there is a concept that people who participate in these activities will be healthier and stronger, and even if they are infected, they will recover smoothly. In the process, they will pass on their immunity to others.
However, as far as coronavirus pneumonia-19 is concerned, we still know little about the short-term and long-term effects of this virus infection, and we don't know how much immunity the infected person can get after rehabilitation. Therefore, it may be very dangerous to deliberately expose healthy people to the virus and let it spread when isolation or city closure may be effective. If these infected people pass the virus on to other roommates, the epidemic will deteriorate rapidly.
After the publication of Imperial College London's research in London, the British government revised its advice to the public and adopted more and more strict control and restriction measures for enterprises and the public.
The age and lifestyle of people in a society will have a great influence on the way of coronavirus pneumonia-19. The researchers analyzed the demography and transmission law of coronavirus pneumonia-19 around the world. There are many elderly people in Italy, and different generations live close together. The death toll from this epidemic is also high. Their research shows that as of March 13, the mortality rate of people over 80 years old is about 14.8%, while the mortality rate of infected people aged 40-49 is only 0.4%.
But even in the hardest hit areas like Italy, keeping social distance seems to have played a role. Bergamo City and Rorty City have taken different measures, resulting in a world of difference in the number of infected people.
On February 2nd, Kloc-0, the first case of COVID-19 in Luoti was diagnosed, and traffic control measures were implemented two days later. Since February 24th, all schools, universities, entertainment and sports activities have also been cancelled. Since February 23rd, cases began to appear in bergamo. Some media discussed whether to implement small-scale restrictions, but these measures were not really implemented until March 8th, when the city was closed.
On March 7th, the number of cases in both cities was about 800, but by March 13, the number of cases of bergamot had increased to about 2,300, while Luoti was only half of that of bergamot, about 1 100. The age structure of the population in these two cities is very similar, and the population over 65 accounts for about 2 1%.
The Italian city of Rorty introduced measures to keep social distance earlier than Bergamo, and as a result, the number of cases in the latter increased significantly.
The situation in these two cities is very similar to that in Philadelphia and St. Louis. But it is too early to say whether history will repeat itself. A big difference between the two is that the Italian data compared by the researchers this time are only confirmed cases, not deaths.
There may be other factors that affect the spread speed of the virus, but considering the similar basic conditions of the two cities and the extreme intervention measures taken by Rorty, we think today's results can strongly illustrate the effectiveness of these measures.
Generally speaking, it is really useful to keep social distance. There is practical evidence to prove the effectiveness of these measures.
A study conducted in Washington, USA, analyzed the overall transmission law of respiratory viruses, and the results showed that keeping social distance can also reduce the spread of diseases in the long run. For example, from 2065438 to February 2009, a large number of schools and workplaces in the United States were forced to close due to snowstorms. As a result, the number of respiratory cases in the United States decreased by 3% to 9% during the rest of this quarter.
The problem is that after people start gathering again, the virus will spread again and the number of cases will increase. Therefore, we may take intermittent, loose and tight social control measures, just like turning on the tap for a while and turning off the tap for a while, so as to ensure that hospitals and medical service personnel will not be overwhelmed.
Of course, it is not easy to keep a distance from friends and relatives, especially during the global epidemic. Isolation may also have some unexpected consequences. In the long run, stopping socializing may be related to heart disease, depression and dementia.
But keeping social distance doesn't mean completely cutting off contact with others. Different from 19 18, with the development of science and technology, we now have many ways to keep in touch with relatives and friends, such as social media, chat software, online video and so on. As long as these practices can protect the people we love, they are all worthwhile.
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