How important is it to keep a social distance during an outbreak?

BEIJING, April 8 (Xinhua) — A severe flu swept the world as world war drew to a close, according tomedia reports. The Spanish flu, which infected more than a quarter of the world’s population and claimed between 50 million and 100 million lives, is one of the deadliest epidemics in human history.

How important is it to keep a social distance during an outbreak?

The gap between Philadelphia and St. Louis during the 1918 Spanish flu reflects the importance of maintaining social distance.

In September 1918, halfway through the pandemic, several U.S. cities were planning a march to promote free public debt. In Philadelphia, Pennsylvania, 600 soldiers have been infected with the flu virus, but city managers have decided to do the wrong thing. Meanwhile, St. Louis, Missouri, decided to cancel the march and took other measures to restrict public gatherings. A month later, more than 10,000 people had died from the Spanish flu in Philadelphia, while st. Louis had less than 700 deaths.

The march is not the only cause of the death gap, but the data still show the importance of these “keeping the social distance” measures during the pandemic. Maintaining social distance means creating a physical barrier between two or more people to stop or suppress the spread of the virus.

An analysis of interventions in several U.S. cities in 1918 showed that peak-hour mortality rates were much lower in cities that banned public gatherings early, closed theaters, schools and churches.

More than 100 years later, the world is experiencing another pandemic, this time caused by a virus called Covid-19. The world’s population is now 6 billion more than in 1918. Although Covid-19 differs in many ways from the Spanish flu, especially in terms of the main impact on populations and mortality, we can still learn an important lesson from the social isolation measures taken during the last flu. This time, keeping your social distance may still be one of the best anti-epidemic measures we can take.

We haven’t found a safe and effective vaccine, nor have we found a specific drug for Covid-19, so our best insurance practice sits on prevention.

Countries around the world are taking a variety of measures to force people to keep their social distance, thereby slowing the spread of the Covid-19. These measures have been lax, with the cancellation of large-scale gatherings, the closure of entertainment venues, bars, schools and other public places, and in some places the policy of complete closure of the city, forcing residents to live in isolation.

Although self-isolation is also a form of social distance, there are important differences between the two. The purpose of self-isolation is to prevent the spread of the virus to others in infected populations, or in people who have had close contact with patients. The range of social distances is broader, with the aim of preventing people from mixing and causing the virus to spread between people.

And the social distance may be long. The latest computer modeling study warns that unless a vaccine or drug is available, or radical isolation measures are in place, social distance measures may need to be maintained intermittently until 2022. This is because, while such measures can delay the peak of the outbreak, the outbreak is likely to be repeated if there is a seasonal change in the virus.

But there is a natural reason why keeping social distance has become such an important anti-epidemic strategy during this outbreak.

In the early stages of an outbreak, an average of two to three people are infected. This ability to transmit is known by epidemiologists as the “number of infections”. In contrast, the number of flu infections ranges from 1.06 to 3.4, depending on the type of strain. According to one study, the number of infections from the Spanish flu is about 1.8. The number of rhinoviruses (one of the viruses that cause the common cold) ranges from 1.2 to 1.83. Most estimates of Covid-19 put the number of infections ranging from 1.4 to 3.9.

The incubation period for Covid-19 is generally around 5 days, but can last up to 14 days. If you’re infected with the new coronavirus and still maintain normal social activity, you may be able to infect two or three friends or family members, each of whom can infect two or three people. As a result, one case would grow to 244 in just one month;

In addition, asymptomatic infections with Covid-19 can also pass the virus on to others, which undoubtedly adds to the complexity of the problem. One study estimated that this asymptomatic infection could account for up to 10 per cent of all cases. It is estimated that between 1 and 3 per cent of those infected do not show any symptoms from start to finish. These people may not know the need for self-isolation, but if they can consciously maintain social distance, they can also inadvertently stop the spread of the virus.

There is already evidence that people staying at home and at a safe distance from others can slow the spread of the virus and halt the domino effect. The study of the outbreak in Wuhan shows that the number of infections in Wuhan has been reduced from 2.35 to close to 1. And when the number of infections reaches 1, the number of cases does not continue to increase.

China’s outbreak models show that strict social distance is key to reducing the number of infections in Wuhan and Hubei. The study concluded that the earlier the outbreak occurred and the earlier the city was decided to close, the smaller the scale of the outbreak would eventually be reached.

One of the main purposes of keeping the social distance is to “flatten the curve”, which slows the spread of the virus. The principle is to extend the spread of the virus in the population, so that the disease later to the peak. The chart shows that if people don’t keep their social distance, the number of infections peaks much faster, and if they keep their distance, the epidemic’s development curve is much slower. As a result, at any point in time, far fewer people will need treatment and medical resources.

What does it mean if it’s really used in real life? Countries have taken a variety of measures to prevent the epidemic. A computer modeling report published by Imperial College on March 16 predicts the spread of the virus. Since then, the UK has stepped up its efforts to prevent the disease.

Scientists analyzed two methods that could be used in the UK and US to fight the outbreak. The first approach is “mitigation”, which focuses on social isolation only for people at risk, mandatory isolation of people who exhibit symptoms, and the second is “suppression”, where everyone needs to take steps, proactively maintain social distance, and those with symptoms and their families need to be isolated at home.

The paper found that if nothing was done, the number of people dying from the new coronavirus in the UK would reach 510,000, and the US could reach 2.2m. Although scientists predict that the first “mitigation” measure could cut the demand for care by two-thirds and the death toll in half, it will still kill hundreds of thousands of people and overwhelm medical services, especially in intensive care.

The report comes after the UK’s hopes of “group immunity”, in which most people in a society gain immunity through infection or vaccine, would significantly reduce the number of people at risk of infection, thereby curbing the spread of the virus further.

When using a group immunization strategy, decision makers are well aware that this practice may promote the spread of the virus, and activities such as mass gathering of people are not prohibited because of the perception that people who participate in these activities will be healthier and stronger, that they can recover smoothly even if they are infected, and that immunity is passed on to others in the process.

But in the case of Covid-19, we know very little about the short- and long-term effects of infection, and it is not clear how much immunity an infected person will receive when they recover (although some tests in monkeys have shown that it is possible to immunize against the virus). Therefore, in cases where isolation or closure may be effective, it may be dangerous to deliberately expose healthy people to the virus and allow it to spread, and if those infected pass the virus to other live-in people, the outbreak will rapidly worsen.

Following the publication of the Imperial College study, the British government revised its advice to the public and imposed increasingly stringent controls and restrictions on business and the public.

The age and lifestyle of the population in a society can have a significant impact on the way Covid-19 is transmitted. The researchers analyzed the demographic and dissemination patterns of Covid-19 around the world. Italy has a larger elderly population and is living closer to each other, and the number of deaths in the outbreak is higher. Their study showed that as of 13 March, the mortality rate for people aged 80 and over was about 14.8 per cent, compared with 0.4 per cent for those aged 40 to 49.

But even in hard-hit areas such as Italy, social distance seems to have played a role. Different measures have been taken in the cities of Bergamo and Lodi, resulting in a world of difference in the number of infections.

The first new crown case in the city of Lodi was confirmed on February 21st, just two days after traffic controls were put in place. From 24 February, all schools, universities, recreational and sports activities were also abolished. Cases have also begun to appear in the city of Bergamo since 23 February, and there has been a media discussion about the need for small-scale restrictions, but they have not really been implemented until they were closed on 8 March.

On March 7th the number of cases in both cities was about 800, but by 13 March the number of cases in Bergamo had grown to about 2,300, while the number of cases in Lodi was only half that of Bergamo, about 1,100. The age structure of the two cities is similar, with about 21 per cent of the population aged 65 and over.

How important is it to keep a social distance during an outbreak?

The Italian city of Lodi introduced measures to keep the distance earlier than the city of Bergamo, which reported a noticeably faster rate of case growth.

The two cities are very similar to Philadelphia and St. Louis. But it is too early to say whether history will repeat itself. One big difference between the two is that the Italian data compared by the researchers were only confirmed cases, not deaths.

There are other factors that may affect the speed of transmission of the virus, but given the similarity between the underlying conditions of the two cities and the extreme interventions taken by Lodi, we believe that today’s results provide a strong indication of the effectiveness of these measures.

In general, it’s useful to keep your social distance. There is actual evidence of the effectiveness of these measures.

A study in Washington state, USA, analyzed the overall spread of respiratory viruses (excluding Covid-19) and found that maintaining social distance can also reduce the spread of disease over the long term. In February 2019, for example, a large number of schools and workplaces were forced to close as a result of a snowstorm, resulting in a 3 to 9 percent reduction in the number of respiratory cases in the United States for the rest of the quarter.

The problem is that when people start gathering again, the virus will start to spread again, and the number of cases will rise. So we may adopt intermittent, time-free social controls, like turning the tap on and off for a while to ensure that hospitals and health care providers are not overwhelmed.

Of course, keeping your friends and family away from them is not easy, and even more difficult during the global pandemic. Isolation can also have unintended consequences. In the long run, eliminating socialization may be associated with heart disease, depression and dementia.

But keeping your social distance doesn’t mean disconnecting from others altogether. Unlike 1918, with the development of technology, we now have many ways to stay in touch with friends and family, such as social media, chat software and online videos. As long as these practices protect the people we love, then it’s all worth it.