Circular on scientific and precise nucleic acid testing services
In accordance with the State Council Joint Prevention and Control Mechanism Comprehensive Group "new coronavirus pneumonia prevention and control program" "on the further optimization of the new coronavirus pneumonia epidemic prevention and control measures to do a good job of prevention and control of scientific and precision notice" requirements, is now scientific and precise to carry out the city's nucleic acid testing services notice of the relevant matters are as follows:
One, the inter-provincial Migrants in the "two stations a dock", continue in accordance with the "voluntary, that is, take away, do not restrict the flow" principle to carry out nucleic acid "landing test".
Second, the red code personnel take the initiative to report to the community, according to the requirements of the residence waiting for door-to-door nucleic acid test. Yellow code personnel to the designated medical institutions to carry out nucleic acid testing, during the norms of wearing a mask, do not take the bus.
Third, risk positions, key personnel as required to implement the "should be examined as much as possible".
Four, nucleic acid testing needs of the public, in the social face of the convenient sampling points at their own expense.
V. Nucleic acid sampling must be standardized throughout the period wearing a mask, and others to maintain a distance of 1 meter, do not talk, do not gather.
Sixth, no new coronary pneumonia-related symptoms, non-risk positions, non-focused personnel and the public without the need to advocate not to carry out nucleic acid testing.
This notice shall come into force on December 4, and will be dynamically adjusted according to the epidemic situation and prevention and control requirements. Thank you for the public's understanding, support and cooperation in the prevention and control of the epidemic in our city.
Extended reading
"Unblocked" after a box is hard to find, you need to prepare antigen kit?
December 2, Chengdu, Tianjin, Beijing and many other places have announced that the subway canceled the nucleic acid proof check. Guangzhou also announced on the same day, all kinds of medical institutions at all levels of general outpatient, emergency room visits personnel with health code green code pass.
On Dec. 1, after the lifting of the temporary control zone for epidemic prevention and control in many districts, the Guangzhou Municipal Health Commission mentioned that it had adopted different nucleic acid testing strategies for different groups of people and encouraged families to prepare their own antigen kits.
Subsequently, some districts began to buy antigen kits in groups, and a number of pharmacies in Guangzhou were out of stock of antigen test reagents.
On December 2, Ding Li, deputy director of the Guangzhou Municipal Market Supervision Administration and spokesman for the press, introduced that Guangzhou was coordinating with the Xin Guan antigen kit producers to reasonably increase their production capacity, and that the maximum capacity of the Xin Guan antigen kits in Guangzhou was about 10.5 million per day at the moment.
On December 2, the Beijing Municipal Health Commission also issued an article mentioning that the public should be the first person responsible for their own health, "do a good job of personal protection and health monitoring, and use a good nucleic acid test, antigen self-testing."
On December 1, the Beijing Health Commission announced the optimization of the daily access to health care measures mentioned that, for the absence of a 48-hour negative nucleic acid results patients, supplementary antigen testing during triage and triage based on test results.
What role will antigen testing play in the future? Who should have antigen testing?
The general population does not need to do antigen every day
In March this year, the New Coronavirus Antigen Testing Application Program was promulgated, opening up antigen testing to three categories of people as a complementary means to nucleic acid testing. These include patients who visit primary healthcare facilities, present with respiratory and fever symptoms and have symptoms for less than five days, quarantine personnel, and residents who have a need for antigen self-testing for early detection and quarantine. However, the Program is mainly aimed at antigen testing for patients by professional medical institutions and testing personnel, and it emphasizes the preferred nucleic acid test.
As early as 2020, some countries in Europe and the United States have used antigen testing, as an adjunct to nucleic acid testing, to screen for new crown infections.
The State Key Laboratory of Virology at Wuhan University has a graphic analogy that visualizes the new crown virus as an orange, with the viral nucleic acid being the orange petal wrapped by the orange peel and inner skin. Antigen detection is to determine whether the virus is present by testing the orange peel or inner peel. Nucleic acid detection, you need to peel both the orange peel and the inner peel, after exposing the orange petal, will be constantly amplified, that is, the gene fragments carrying the virus is constantly amplified, in order to be detected by the instrument, and ultimately determine the presence of viral nucleic acid.
The antigen test is easy to perform, with results coming in 10 to 20 minutes, and is inexpensive. But it is less accurate than nucleic acid testing.
In March this year, Li Jinming, deputy director of the National Health Commission's Clinical Laboratory Center, said the sensitivity of antigen test reagents already approved by the state is between 75% and 98%, and the specificity is between 95% and 99%. Li Jinming mentioned that antigen test can not replace nucleic acid test, when the antigen test is positive, must take the nucleic acid test for confirmation.
The CDC also mentioned that antigen testing is not as accurate as nucleic acid testing and may not detect the virus in people in the early stages of infection or who are asymptomatic, recommending that testing be done for 2 to 3 consecutive days and that "home antigen self-testing is not perfect, but provides a quick and easy option for detecting whether or not you are infected with a new coronavirus."
Jin Dongyan, a professor at the University of Hong Kong's School of Biomedical Sciences and an expert in virology, pointed out to China News Weekly that, currently, about 60 to 75 percent of all confirmed cases in Hong Kong are found to be self-tested for antigen. Large-scale studies in the United States have shown that after three consecutive antigen measurements, its specificity and sensitivity are very close to that of nucleic acid, which can identify roughly 98% of infected people, "can be measured every day, or every other day, usually 3~5 days should be measured at least three times consecutively".
A public health expert, who did not want to be named, emphasized that the nucleic acid test can quickly screen out infected people when the number of infected people is small in the early stages of the development of the new crown epidemic. However, when there is widespread social surface transmission, centralized nucleic acid testing is prone to cross-infection and unequal risks and benefits. In contrast, antigen testing, which has a low threshold and can be performed by people at home with reference to instructions, can effectively avoid that risk.
Who should undergo antigen testing? In what scenarios is antigen testing used?
During Hong Kong's fifth wave of the epidemic, the SAR government gave every household 10 to 20 boxes of antigen test reagents and required self-testing for three consecutive days. "At that time, a considerable number of relatively hidden infected people were identified at once." Jin Dongyan said. He suggested that in the early stages of a large-scale outbreak, the first round should first try to test as many antigens as possible, on the one hand, antigen detection results quickly, can improve the efficiency of the initial screening, to find out potential infected people, and then find out the entire chain of infection; on the other hand, antigen detection costs less than nucleic acid, can effectively alleviate the grass-roots level of the financial burden.
A number of experts believe that most ordinary people do not need to do antigen testing every day. Antigen testing is mainly used for screening high-risk groups. Jin Dongyan said that in Hong Kong, two groups of people need to undergo antigen tests continuously, high-risk and specific groups. High-risk people include elderly people and employees of nursing homes, health care workers, staff in the front line of quarantine, such as quarantine hotels, airport employees. Specific cohorts, on the other hand, are dynamically adjusted according to the high-risk points involved in the positive patient, for example, people circled near locations where the positive patient was associated with a stay of more than two hours or locations where sewage samples were tested and found to have extremely high viral loads.
Jin Dongyan believes that the antigen can also be considered in the future as an entry and exit credential for specific places such as schools, hospitals and shopping malls to ensure the necessary functioning of society. He cited the example of Hong Kong students before going to school every day, to do the antigen test at home in advance, health care workers should also be measured antigen before going out to avoid hospitalization. In addition, an infected person or a close contact in the community or home quarantine on the sixth and seventh days, respectively, two antigen test, if two consecutive days of the test results are negative, then the quarantine can be lifted.
According to the Twenty Rules for Optimizing Prevention and Control, in areas where no outbreaks have occurred, nucleic acid testing will be carried out on risky positions and key personnel in strict accordance with the scope determined in the ninth edition of the prevention and control program, and the scope of nucleic acid testing should not be expanded. In addition, according to the ninth edition of the prevention and control program, after the emergence of one or more cases of indigenous outbreaks in the jurisdiction, in addition to completing a full nucleic acid test, the follow-up can be based on the results of the test and the risk of the spread of the epidemic, the nucleic acid sampling of key institutions such as schools, nursing homes, etc., at the rate of at least 20% of the sampling ratio per day.
The aforementioned public health experts told China News Weekly that if full nucleic acid testing is not carried out in the future, from the point of view of discovering the chain of transmission, nucleic acid testing in such key institutions at a sampling rate of 20% "is definitely not enough" and should be supplemented by antigen testing, "preferably every day, or at least 3~3 times a week. It should be supplemented with antigen testing, "preferably on a daily basis, or at least three to five times a week".
Jin Dongyan explained that antigen and nucleic acid tests are complementary. After a positive antigen test, nucleic acid is used to determine the infected person's viral load and risk, which is used as an important basis for appropriate isolation measures, and "good steel is used on the knife edge". In addition to continuous antigen testing for high-risk individuals, Hong Kong also requires weekly nucleic acid testing, which is equivalent to "double insurance".
Lu Mengji, a German-Chinese virologist and professor at the Institute of Virus Research at the University of Essen Medical School, told China News Weekly that the biggest advantage of expanding antigen testing is that it can directly screen out "some of the super-transmitters" and isolate them in time.
On Dec. 2, Guangzhou announced that hospitals at all levels will be required to provide green code access for general outpatient and emergency room visits, and that newly admitted inpatients and their companions will need to enter with a 24-hour nucleic acid-negative certificate. Jin Dongyan analyzed that, in contrast, the risk of hospitalization is higher, so the requirements for admission are also high. But he suggested that more antigen testing can be supplemented with nucleic acid to reduce the risk of hospitalization.
"Not just a medical topic, but a topic of social management"
After the introduction of the Program, since April this year, Shanghai, Hebei and other places have implemented antigen testing as a complementary means of nucleic acid testing.
A number of experts interviewed mentioned that antigen testing is a general trend, which also helps to reduce the cost of epidemic prevention. However, in the opinion of the aforementioned public health expert, if antigen testing is to be implemented, the requirements for systems and management are higher than those for nucleic acid testing. He said, "Before, people only needed to cooperate with nucleic acid testing, but after antigen testing, who bears the burden of the money for testing, whether it can cover all the people, and how individuals can accurately report the results all need to be considered."
In his view, this is not just a medical issue, but a subject of social management. And at present, Guangzhou is only encouraging families to bring their own antigen kits, but no specific requirements have been issued on how to implement them.
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Guangzhou encourages families to provide their own antigen kits after a netizen on social platforms, previously free nucleic acid test, not adapt to the antigen self-testing but also out-of-pocket expenses.December 2, Guangzhou Tianhe, Haizhu District and other districts began to launch self-funded nucleic acid convenience sampling points, mixed tube charge of 2.8 yuan per person, the major hospitals of nucleic acid testing services also began to resume self-funding, a single tube for 13.5 yuan. In contrast, antigen detection reagents are mostly sold for less than 10 yuan for a single person.
Jin Dongyan said that in Hong Kong, the SAR government distributes free rapid antigen test kits to the two high-risk groups. If more infected people have recently appeared in a certain neighborhood or building, a joint team formed by the University of Hong Kong and the SAR government will also test the nearby sewage, and if a high viral load is found in the sewage samples, antigen test reagents will be distributed free of charge to the nearby residents, cleaners and property management staff. The rest of the population will have to pay for them at their own expense, and employers of some organizations will also provide antigen reagents to their employees free of charge.
Secondly, the question of whether individuals will report the results of antigen tests accurately is also something to think about. "Building a reporting system, ensuring the accuracy of the reporting system, as well as auditing antigen reagents to drive poor-quality manufacturers out of the market, requires further mapping by state regulators." Jin Dongyan told China News Weekly.
Some cities have already set up reporting platforms.In April, in response to the Program, Guangdong Province's Health Commission had launched the "Guangdong Antigen" applet, which supports residents to carry out antigen test information collection and result reporting, and connects with local Yuejian Tong, Yue Nucleic Acid applet, e-health code, etc.In May, Hebei Province went online with the "Antigen Jie Report". In May, Hebei Province launched the "Antigen Ji-report" app. The Beijing Municipal Health Big Data and Policy Research Center also launched "Beijing Antigen", which allows citizens to upload antigen test results through the app.
Jin Dongyan introduced, in Hong Kong, the aforementioned key places in the daily antigen self-test, found positive, can be automatically reported through the "rapid antigen test positive results declaration system", the system was launched by the Hong Kong Department of Health Center for Health Protection in March. To encourage people to take the initiative to use the system, if residents upload their antigen results on the system and book a nucleic acid appointment, the government will issue a free gift pack, which includes a guidebook on immunization, Lianhua Qingdian, fever-reducing medication, an electronic thermometer, 20 packs of antigen test reagents and 20 KN95 masks. Residents who do not use the system to report the disease will have to bear hundreds of dollars of testing costs at their own expense.
He added that in order to further verify the accuracy of the antigen test, Hong Kong would conduct regular sampling tests with nucleic acids on 10-30 percent of the reported antigen-positive patients.
But the above public health scientist emphasized that promoting antigen testing and making the individual the first person responsible for his/her health is demanding in terms of social management. In addition, he suggested that if antigen testing is to be promoted, how it should be implemented and regulated should not be interpreted by localities, but adjusted and modified in the new coronavirus pneumonia prevention and control program, which will help localities to implement it in accordance with the unified regulations.
Written by Yang Zhijie Huo Si Yi