In epidemic prevention and control and
Weighing the pros and cons between economic and social development,
The difficulty is very large,
But there is already a glimmer of hope.
Author: Yang Xueyi
Edit: Yu Bing
Editor: Ling Yun Xu Chenjing
Recently, the new crown virus antigen test kit has been put into use and sparked a heated discussion.
With test kits, people can test themselves at home and wait 15-20 minutes for the results.
Once a mild patient is diagnosed, he will be sent to a designated location for centralized isolation management, and eventually recover by taking relevant drugs. He then only needs home health monitoring for 7 days.
These changes are related to the recently issued "Diagnosis and Treatment Plan for Novel Coronavirus Pneumonia (Trial Version 9)" (hereinafter referred to as the new version of the Diagnosis and Treatment Plan) and "Guidelines for the Implementation of Regional Nucleic Acid Testing Organizations (Third Edition)" (hereinafter referred to as the new version of the Nucleic Acid Testing Guidelines).
However, some people mistakenly believe that the adjustment of the new version of the diagnosis and treatment plan is a signal of "looseness", and some people even say that this is a preparation for "lying flat".
On some issues of public concern, the global people reporter interviewed Wang Guiqiang, a member of the medical treatment expert group of the joint prevention and control mechanism of the State Council and the director of the Department of Infectious Diseases of peking University First Hospital.
Wang Guiqiang, member of the medical treatment expert group of the joint prevention and control mechanism of the State Council and director of the Department of Infectious Diseases of the First Hospital of Peking University
After asking one "why" after another, steadfastness, longing and hope also followed.
Why is "lying flat" not feasible at the moment?
First of all, Wang Guiqiang especially wants to correct the misreading of "lying flat".
"Aumechon, although less pathogenic, is highly contagious. Our country's per capita medical resources are relatively limited, and once there is a large-scale outbreak of the epidemic, it will inevitably cause a run on medical resources or even collapse, resulting in the death of a large number of new and non-new crown patients. ”
In addition, although the fatality rate is not high, the population base of the mainland is large, and once it is "lying flat", the absolute number of deaths will be large.
"The elderly, in particular, are at high risk of severe illness and death. We have about 52 million people over the age of 60 who have not been vaccinated, and even if the case fatality rate is only 1%, there will be more than 500,000 people. Moreover, the elderly are often accompanied by underlying diseases and are the first to bear the brunt of high disease deaths. Once the above consequences occur, we absolutely cannot accept it! ”
"So, we're still calling for vaccinations. This not only has an effect on forming a national immunization barrier and reducing large-scale outbreaks, but more importantly, it reduces the case fatality rate, especially for high-risk groups such as the elderly. ”
Why is this wave of the epidemic so strong?
The joint prevention and control mechanism of the State Council introduced at a press conference on March 22 that from a global perspective, the current western Pacific region is in the peak epidemic stage of the epidemic, affected by the high epidemic situation in neighboring countries of the mainland and the Hong Kong Special Administrative Region, the recent imported cases outside the mainland have increased significantly, and the pressure on foreign defense imports has increased significantly. This is closely related to the current epidemic situation on the mainland.
"The new coronavirus is an RNA (ribonucleic acid) virus, which is characterized by high variability." Wang Guiqiang said that after more than two years of mutation, the R0 value of the virus (the number of individuals infected by the virus) has been increasing. "The Delta virus doubled, and now the Opmiqueron is three times that of Delta, and the conservative estimate of the R0 value of the Olmikron is at least 8."
Nucleic acid detection Ct value (cycle number threshold) is another measure of infectivity.
Simply put, after the nasopharyngeal swab is collected, the professional will continuously amplify and replicate the viral nucleic acids that may exist in the reaction tube, and the Ct value refers to the number of cycles required for the fluorescence signal in the reaction tube to reach a set threshold.
The smaller the Ct value, the more viral content the sample is and the more contagious it is. "Initially, the Ct value of 20 was relatively high, and by the time of Omikeron, the Ct value was often lower than 10."
Wang Guiqiang said that although the Omiljung strain itself is more contagious, the pathogenicity has weakened. "We found that the amount of virus in the upper respiratory tract was very high, but the amount of virus in the lower respiratory tract and lungs was very small, resulting in a very low proportion of pneumonia."
He introduced that in this round of the epidemic, the main people are mild and asymptomatic infected, accounting for more than 95%.
"The biggest problem caused by the increase in asymptomatic infected people is that it cannot be found in time, and the difficulty of prevention and control has increased." When the first patient is found, there may have been multiple generations of transmission in the past, and there is already a certain size of infected people, so epidemiological investigation is very difficult. ”
Compared with a year ago, the epidemic prevention situation of the Chinese people is also different. More than 80 per cent of people have been vaccinated and have gained some immunity, but this has led to an increase in mild cases and asymptomatic infections.
"In addition, due to the long duration of the epidemic, individual regions and populations have slackened or neglected the prevention and control of the epidemic, resulting in the rapid spread of the epidemic." Taking campus infection as an example, "usually the degree of gathering is high, students attend classes, self-study, eat in the canteen are all together, if the mask is not enough, these weak links will lead to the outbreak of the epidemic, it is worth raising vigilance." ”
Why increase antigen testing?
In terms of case detection, in addition to continuing to adhere to nucleic acid detection, the new version of the diagnosis and treatment plan has added antigen detection as a supplement, improving the ability of early detection of cases.
Compared with nucleic acid testing, antigen detection is convenient and fast, similar to the colloidal gold test strip method of the usual pregnancy test, and the operation is simple.
In Wang Guiqiang's view, antigen detection can share the inconvenience and hardship of nucleic acid testing among the people, and can also reduce the increased risk of virus transmission due to nucleic acid testing aggregation.
However, antigen testing has a distinct disadvantage: false positives can occur.
According to the press conference of the joint prevention and control mechanism of the State Council, the sensitivity of antigen detection reagents approved by the state is 75%-98%, and the specificity is 95%-99%.
In view of the fact that the prevalence of the population in most parts of the country is less than one part per million, if you take a test kit with 85% sensitivity and 97% specificity and screen in cities with tens of millions of people, you will get 300,000 positives, of which only 9 are true, and these 300,000 people can be tested for nucleic acid.
This avoids nucleic acid testing for all employees to a certain extent and improves efficiency.
New coronavirus antigen detection kit.
"Antigen testing is an effective way to solve the shortage of nucleic acid testing capabilities in the face of the outbreak of the epidemic, and now written into the diagnosis and treatment plan, an important role is to take precautions and think of danger in times of peace." Wang Guiqiang said that in view of the recent epidemic situation in Hong Kong, combined with the characteristics of the Olmikron strain, we must make full preparations, "rather prepare than fight, and not fight but not prepare" to ensure that we do not fight a battle without preparation.
"But it needs to be emphasized that antigen testing is still only an important supplement, and can not be used as an important basis, if the antigen test is positive, regardless of whether it is true or false, nucleic acid testing should be carried out immediately to confirm." At the same time, it is mainly used for personnel testing such as control, sealing and control, and close contact, and it is not recommended for ordinary people to conduct testing. Wang Guiqiang said.
Why is the de-quarantine metric adjusted?
The new version of the diagnosis and treatment plan clarifies that the Nucleic acid detection Ct value of convalescent infected people can meet the criteria for discharge or release from isolation ≥ 35. The previous standard for the negative nucleic acid test of the new crown virus in China was the Ct value > 40.
This means that a slight reduction in the standard will shorten the length of hospital stay for infected people in order to maximize the full use of limited medical resources.
"This stems from the closed-loop management of this year's Beijing Winter Olympics. We found that some foreign athletes had Ct values of 38 and 37, and according to the standards at that time, they could not participate in the competition. However, through the argument of our expert group, it is agreed that the Ct value ≥ 35 does not have to be isolated. This is based on the fact that most of the standards for nucleic acid testing in foreign countries are bounded by 35, and studies have shown that more than 35 cannot isolate the virus, and there is no contagiousness. ”
Wang Guiqiang said that after the practice of the Beijing Winter Olympics, they were further convinced that this standard was safe and wrote into the new version of the diagnosis and treatment plan.
Another important adjustment is to continue 14 days of isolation management and health monitoring after discharge to 7 days of home health monitoring after discharge.
"At that time, it was set at 14 days because there were Fuyang patients, and the number of isolation days was increased for the sake of insurance. But later, a lot of research was done in China, and foreign scientific research teams also had some research. These findings suggest that the virus cannot be isolated in about 10 days. Through further research, we adjusted the 14 days to 7 days on the basis of two negative nucleic acid tests in the discharge. ”
It can be seen that the Joint Prevention and Control Expert Group of the State Council has been accumulating experimental and practical experience, and has constantly put forward more scientific and standardized plans.
"Whether it is the new version of the diagnosis and treatment plan or the new version of the nucleic acid testing guidelines, it is to adhere to the supremacy of the people and the supremacy of life, and strive to achieve scientific precision and dynamic clearance." This is not only to adapt to the current epidemic situation, but also to try to recover the losses caused by the epidemic to the economy and society. ”
Wang Guiqiang said that it is very difficult to weigh the pros and cons between epidemic prevention and control and economic and social development, but he has seen the dawn of hope.
"In any case, the epidemic situation this year is clearer than last year. With the in-depth study and judgment of the epidemic situation and the solid advancement of many preliminary work, the epidemic prevention and control strategy will keep pace with the times, scientific and accurate, and dynamically adjusted! ”
This article is excerpted from "Interview with experts of the joint prevention and control mechanism of the State Council on the seven "whys" of the epidemic in this round"
The full text was published in the 466th issue of Global People magazine
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