On March 11, the Comprehensive Group of the Joint Prevention and Control Mechanism of the State Council released a major news. To promote the monitoring mode of “antigen screening, nucleic acid diagnosis”. Residents can purchase antigen detection reagents to self-test for the new crown if they need it.
Image source: People’s Daily Weibo
It has been more than two years since the outbreak of the epidemic. Everyone has become accustomed to the centralized nucleic acid testing of the new crown, and has also initially learned that other countries allow antigen testing. What’s the difference? What does the liberalization of our country mean?
Today is hotly debated, and today I will briefly talk about the antigen detection of the new crown.
Faster and more convenient antigen testing
Simply put, the structure of the new coronavirus is divided into two parts, an RNA nucleic acid inside, and a protein shell outside.
Nucleic acid testing is to find out whether there is new coronavirus RNA in the test specimen. The amount of viral RNA is small, and it is cyclically amplified by RT-PCR technology to make them more detectable. The fewer cycles required, the higher the amount of a specific nucleic acid in the sample.
The antigen detection kit is mainly a rapid antigen detection technology. The polyclonal antibody against the new coronavirus nucleocapsid protein is labeled, and the nucleocapsid protein antigen on the surface of the virus in the sample can be found by pairing. It’s like there is a new coronavirus in the sample.
This method is much faster than amplifying nucleic acid over and over again. It is operated by yourself like a pregnancy test stick, and the results are immediately available.
Why not choose antigen testing before?
Nucleic acid testing is more accurate. While no test is perfect, nucleic acid tests are clearly closer to perfection than antigen methods. The data shows that the commonly used antigen detection kit is only 58% accurate for asymptomatic infections.
The data is relatively simple. Nucleic acid detection can know the level of the virus by the way, which is helpful for analyzing subsequent changes and controlling the epidemic as a whole. Antigen tests can only tell if there is an infection or no infection.
Data sharing is not easy to achieve. Nucleic acid testing is carried out in institutions, and the results are online to facilitate query and lock. Antigen self-testing and reporting rely on self-consciousness, which is not conducive to tracing the source of the epidemic.
So generally speaking, when nucleic acid detection is capable, nucleic acid detection is still the mainstream.
Why is antigen testing now available?
The focus is on the differences in different periods of anti-epidemic.
The sensitivity rate of antigen detection is low. For areas with better epidemic control, the infection rate in the population is low, and it is obviously not cost-effective to choose such a low-sensitivity detection method as antigen. of. But when the epidemic is more serious, and the number of infected people is relatively high in a community or school, it makes economic sense to use antigen testing.
At present, the domestic epidemic situation is spreading and growing rapidly. Some regions have the conditions to use antigen testing. For example, there is a clustered transmission in Jilin City. In this case, it may not be the best arrangement for everyone to line up for testing, because it cannot be tested all at once, and many people gather for testing, which will increase the risk of infection, and it is not safe.
Antigen test kits are also distributed for everyone to test themselves, so that they can know more quickly whether the tester is infectious and isolate the most infectious patients early.
Antigen detection and nucleic acid detection should complement each other. Nucleic acids and antigens are both important testing methods, and they have their own most applicable occasions. For example, when there is no nucleic acid detection capability, such as being far away from the test site, or having fever or cold symptoms in the middle of the night, a more convenient antigen test can be used.
What will the future hold for us?
Today, antigen testing is still a supplement, not a major change in epidemic prevention.
The immediate and visible impact is mainly to reduce the pressure on grass-roots epidemic prevention and medical workers.
Secondary and tertiary hospitals often face admissions of patients who may be judged by doctors as not suffering from the new crown, but with fever or respiratory symptoms. According to the current epidemic prevention policy, nucleic acid must be screened first, otherwise doctors must wear protective clothing for consultation, and patients cannot enter ordinary dialysis rooms, ICUs and operating rooms. If you encounter emergencies such as maternal, dialysis, and even cardiovascular and cerebrovascular diseases, delays may be caused.
If there is an antigen test, those with emergency needs can do the antigen first to reduce the risk. There are also many grass-roots medical institutions that originally depended on dealing with some daily diseases to maintain operation, but during the epidemic period, they were unable to receive patients with fever and respiratory symptoms. With antigen testing, it is more convenient for ordinary people to see a doctor, and it is also guaranteed for grass-roots medical institutions. It is not necessary to send all patients who need nucleic acid testing to higher-level hospitals, and many conflicts between doctors and patients will be alleviated.
Is the release of antigen detection also a signal of subsequent changes in anti-epidemic?
At the press conference held after the closing of the Fifth Session of the 13th National People’s Congress on March 11, a reporter asked: The new crown pneumonia epidemic has lasted for two years, whether China will consider the current dynamic Zero epidemic prevention and control policies become more sustainable? Is there a roadmap open to the world?
Premier Li Keqiang said: “Since the outbreak of the epidemic, I have talked with heads of international organizations and entrepreneurs of multinational companies, and they all hope to get necessary exchanges. We have opened fast lanes and Green channel, guaranteenormal production and operation. We will continue to accumulate experience, respond to possible changes in a timely manner, and gradually make the flow of logistics people orderly and smooth. “
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Planning: Eric | Producer: Feidi
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