COVID-19,SARS-CoV-2 z-bo 2020-10-30 426

　　As we enter the last quarter of 2020, the SARS-CoV-2 that has plagued us for a year does not seem to disappear. In the absence of vaccines and widespread effective therapies, some people believe that we should learn how to deal with COVID- 19 Coexistence, so is it actually like this? This may be a complicated question. Should we allow SARS-CoV-2 to spread in most people while protecting the elderly and people at high risk of serious diseases, so as to form a certain degree of potential immunity in the population? Or continue to take control measures to eliminate the virus?

　　When trying to answer this question, researchers will put forward a concept called "herd immunity", that is, about 60% of the population will be immune to a certain disease, through the establishment of natural immunity in the population Controlling infectious diseases does not seem to have been achieved before. Herd immunity can be achieved through targeted vaccination, and scientists have not yet developed a vaccine against COVID-19.

　　Take smallpox as an example. It is a highly contagious disease and the only human virus that has been eliminated by humans. Unlike COVID-19, patients infected with variola virus always have symptoms, so it can be effectively detected. They are quarantined, and anyone who has not died will be protected for life. However, only through a cooperative vaccine campaign can we completely get rid of the virus, and only in this way can we achieve a sufficiently high level of protection on a global scale, which is also the threshold for herd immunity.

　　About a quarter of the common cold is caused by multiple types of coronavirus infections. Since SARS-CoV-2 is also a coronavirus, is there a similar protective effect? At present, researchers do not know how long the protective ability of the body can last when the infected person recovers, but we know that this protective effect will not last forever. For example, a recent study showed that some people will be infected with the same type of coronavirus more than once in the same winter. This indicates that natural immunity may not be assumed to be a fact of the relationship between the population and the coronavirus. And herd immunity does not seem to happen naturally. Indeed, if we can obtain natural immunity without a vaccine, it may be very remarkable, because this situation has not happened before.

　　So what if SARS-CoV-2 is completely eliminated by controlling its spread? This may be the situation of its close relatives SARS-CoV and MERS-CoV, which are also related to bat coronaviruses. The sudden emergence of these diseases in the 21st century may provide an effective pathogen for the human immune system. So this Two viruses may be able to help researchers effectively predict the development trend of COVID-19. From November 2002 to May 2004, SARS was epidemic twice globally and then completely disappeared, thanks to the strict control measures at that time, such as quarantining all people who had contact with the infected and regularly quarantining public areas Perform disinfection and cleaning. In addition, researchers have formulated a strong laboratory testing program to encourage people to wear masks and wash their hands frequently. These measures can effectively block the spread of the virus between people, and thus can completely eliminate the spread of the virus. MERS was first discovered in the Middle East in 2012. It can cause very serious diseases. 34% of infected people have died. It seems to be less infectious than SARS-CoV-2 and SARS-CoV. The spread of MRES requires very close contact between people. There are still large-scale outbreaks of MERS, such as the 199 cases of MERS in Saudi Arabia in 2019.

　　Like MERS, but unlike SARS, researchers can speculate on the outbreak of COVID-19. Even if we control it more or less, it will appear from time to time. However, the current key situation is to determine the infected population as soon as possible. Through testing and contact tracing, the number of affected people will be reduced, and effective and widespread vaccination will also be more effective in controlling the spread and spread of the disease.

　　The antiviral drug Remdesivir is currently only used for severe COVID-19 patients admitted to the hospital, and as of the spring of 2021, it seems unlikely that the vaccine will be developed, but at the same time there may be some new SARS-CoV-2 viruses The strain, unfortunately, is either the same as the original strain or more infectious than its strain. SARS-CoV-2 has not yet stabilized. Most patients infected with COVID-19 can recover, but currently about 3% of positive patients worldwide have died. Researchers do not know exactly what percentage of recovered patients will have long-term side effects. A proportion is even as high as 10%. Researchers conducted a study on SARS patients who were infected in early 2000 and showed that some of them will still have lung health problems 15 years later.

　　Faced with such statistics, we should strive to ensure that as many people as possible are free from COVID-19 infection, instead of learning how to coexist with the virus, we need to continue to take daily measures to stop the spread of the virus in the population as much as possible. So this means that many countries will adopt different degrees of blockade in 2020. We really need to limit people’s freedom and achieve a certain dynamic balance between allowing them to gather with their relatives and earn a living. SARS-CoV-2 is not like smallpox, SARS or MERS. We cannot learn from previous infectious diseases. At the same time, this is beyond the scope of our unclear understanding of concepts such as herd immunity, elimination or learning to coexist with viruses.

　　It seems that the SARS-CoV-2 outbreak will become a reality in the future, but learning how to coexist with the virus does not mean that it will infect a large number of people. The plan made by the researchers is to ensure that fewer people will be infected. So that the scale of the new outbreak is small and rare.