The approval of 11 antigen self-test products can change China's anti-epidemic situation?

On March 11, the National Health Commission issued a document that the long-discussed antigen self-test finally opened the floodgates and began to be trialed as a supplementary program for new crown testing.

Previously, the antigen testing products that were "cold" in the country were hot for a while, and it originally took 1 to 3 years to complete the approval process, and now they are pouring into the market at an unprecedented speed. In just 3 days, 11 domestic products have been approved.

"It must be very urgent," an industry insider told Eight Point Jianwen, "the day before yesterday batch of 5, today batch of 5." A manufacturer can produce up to 1.8 to 2 million kits a day, and its production capacity will certainly not keep up with the needs of 1.3 billion people. ”

In the face of increasingly tight products, government emergency procurement, chain pharmacies and e-commerce platforms have grabbed goods:

Jilin Province, which has more than 2,000 new infections in a single day, has quickly docked with enterprises such as Beijing Heatscape Biology and Guangzhou Wanfu Biology, and ordered 12 million antigen detection reagents from the whole country.

Rapid detection kit for SARS-CoV-2 antigens of the new coronavirus

Communities in Hangzhou have distributed COVID-19 self-test boxes to residents free of charge. Hangzhou even used unapproved products in advance to cope with "the most severe and complex epidemic this year".

Eight points of health news learned that some approved enterprises received many government orders, they told each other, "directly take the official letter."

In Jiangcheng, Wuhan, the first batch of antigen self-testing kits that some pharmacies just put on the shelves were snatched up in just a few hours.

Tmall Health, JD Health, Meituan and other e-commerce platforms also announced the start of selling antigen self-test products, although many products are still in the pre-sale stage.

Whether it is for public health policy or commercial interests, the stockpile of antigen testing products is in full swing.

In the case of a domestic infection rate of much less than 1%, can this newly injected "fresh force" reverse the passive anti-epidemic situation? Does the use of antigen testing to check for leaks and fill gaps indicate the loosening of the epidemic prevention situation?

Unable to test nucleic acid

The reason why antigen testing has been approved by the line of fire and clustered in various places on a large scale is mainly because of the continuous epidemic since the beginning of this year.

Several Chinese cities, including Hong Kong, have been plagued by Obi Kerong, and in the past week, Shanghai, which has been regarded as a top student in the fight against the epidemic, has broken the defense, And Jilin has increased infections by more than 1,000 infections for three consecutive days, and the number of confirmed cases reached a record 3076 yesterday.

The number of infected people in the country has also reached a new high, and the epidemic situation in China has reached the first national peak after the clearance of Wuhan, and China's tried and tested nucleic acid testing methods have encountered major challenges.

Unlike nucleic acid testing, which requires specialized laboratories and professionals to perform, antigen testing is more convenient and faster, requiring only a pregnancy test-like kit, operated by the user himself, and the results can be seen after 15-20 minutes.

However, this convenience also brings hidden worries to the reliability of antigen detection - the user's sampling and the threshold of the kit affect the sensitivity of the antigen detection, and the false yin of the negative is mistakenly judged as positive, and the false yang that the positive cannot be detected is not uncommon. Therefore, for a long time, although antigen detection is fast and convenient, it cannot meet the needs of fighting the epidemic for the purpose of "zeroing" because the results are not reliable enough.

For a long time, nucleic acids and "zero policy", antigens and "mild disease at home" have been considered the perfect golden combination. This has also led to the approval of antigen testing reagents will be crudely interpreted as: is the anti-epidemic policy going to shift?

However, under The Secret Kerong, the nucleic acid testing of all staff may not only bring the risk of cross-infection due to the queue gathering of the crowd, but also because of its relatively complex detection cycle, so that the test results can not help but lag behind the real-time development of the epidemic. In a word, nucleic acid testing is really "slow".

Liang Zichao, a Hong Kong respiratory specialist and former chairman of the Infectious Disease Advisory Committee of the Hong Kong Medical Association, introduced: "After a patient is infected with Omilon, he can transmit the virus to his family within 24 hours, and some patients may also go out, bringing more risks of infection." ”

In the face of the Omicron mutant, "fast" is the first problem that needs to be considered. Nucleic acid testing, like a photograph that needs to be printed to be shown, records only a few days ago, and in the face of Aumicron, it requires an almost "live" screening measure.

In fact, the data obtained after combing through the relevant information of some cities with recent epidemics almost confirmed this - for large cities, if nucleic acid testing is to be carried out for all employees, even if there is external support and full horsepower testing, it will take at least 2 days to complete a round. 2 days, enough for the Arcane Kejong to spread for one generation.

In fact, in the large-scale epidemic that has occurred in many cities, at the peak of the epidemic, the slowing of nucleic acid sampling and detection has become almost the norm. Queuing up for nucleic acid has become the norm, people have a fever, and complaints about nucleic acid sampling before the wheel have become the standard of a certain scale of the epidemic.

On March 12, there were 2,156 new infections in Jilin Province, and at the local press conference, the relevant staff introduced that at this time, Jilin City had completed the sixth round of nucleic acid testing for all employees. Obviously, in this large-scale epidemic, nucleic acid testing has almost become a role that is exhausted after the epidemic.

Antigen detection on the line of fire, patching the screening

In the context of the outbreak of the epidemic in many places, the antigen test that can produce results in only 15-20 minutes is almost on the line of fire.

After the outbreak of the epidemic in Jilin Province, on March 13, When investigating and guiding the prevention and control of the epidemic in Jilin Province, Sun Chunlan, vice premier of the State Council, stressed that it is necessary to accelerate the screening of infected people, use a combination of nucleic acid and antigen detection, improve testing capabilities, optimize organizational implementation, and find out the background of the epidemic as soon as possible.

At the epidemic press conference in Jilin Province on the afternoon of March 14, relevant departments said that Jilin Province had urgently ordered 12 million antigen test reagents.

In addition to Jilin, at present, the Yuhang District of Hangzhou Has also begun to use antigen detection.

The relevant person in charge of the Yuhang District Party Committee told Eight Points Jianwen that Yuhang District issued antigen testing reagents to the public on March 13, "Temporarily distribute it to try it." The product is donated by the company, and this product is not yet on the market. ”

Relevant people from the Xiamen Municipal Health Commission said that Xiamen is considering the implementation of antigen + nucleic acid detection mode, and there are enterprises in Xiamen that produce antigen detection reagents, which are not currently listed. ”

All of this means that while nucleic acid testing is still the gold standard for confirming the diagnosis, antigen testing has quickly joined the epidemic prevention and control work and has become one of the important components of "early detection".

In fact, a number of experts have told Eight Points that from a professional point of view, the scale and degree of the outbreak in Jilin is indeed very suitable for the use of antigen detection + nucleic acid detection mode.

In the early stage of the epidemic, because of the high sensitivity and good specificity, nucleic acid detection has great advantages, but for nucleic acid detection that requires fine operation, when the workload reaches a certain threshold, the amount of detection begins to become an obstacle to speed, and the time cost of nucleic acid screening will rise sharply.

"Antigen detection has obvious advantages when large-scale detection is required, and only one detection package is needed to achieve rapid on-site screening." Chang Rongshan told Eight Points Kenwen. Compared with nucleic acid detection, antigen detection does not require an instrument and can be operated on the spot, and a single sample generally only takes 20 minutes to produce results.

An expert, who did not want to be named, told Eight Point Jianwen that when the screening strategy for infected people was formulated in China, nucleic acid testing was too highly regarded as a guideline, and the accessibility of nucleic acid testing at the grassroots level and the reality of poor efficiency in the face of large-scale epidemics were not taken into account. Now in the face of the attack of Omicron, finally considering antigen detection as a supplementary testing method, it can be said that the best choice in line with the current epidemic situation has been made.

The introduction of antigen detection not only makes up for the shortcomings of nucleic acid detection speed, but also the population screened out by antigen detection is often the most contagious and the one that needs to be isolated and controlled the most. Jin Dongyan even told Eight Points Jianwen that the introduction of antigen detection as a supplement to nucleic acid detection precisely reflects the idea of accurate prevention and control, because the people who test positive for antigens are often the groups that need to be found in the epidemic.

Jin Dongyan explained: The accuracy of antigen detection depends on the viral load of the sample, and in the group with a CT value (the lower the CT value, the higher the viral load) of less than 25, the sensitivity of antigen detection is very high, and it can almost match 100% with nucleic acid detection.

"People with a CT value of less than 25 are generally in the acute infection stage, have a high viral load in the body, have a strong transmissibility, and need to be controlled and isolated."

Liang Zichao said that in the early days of this round of epidemic in Hong Kong, the nucleic acid detection method was used to screen infected people, but due to the rapid expansion of the scale of the epidemic, the speed of nucleic acid testing could not keep up with the development of the epidemic, so antigen detection began to be used.

Although antigen testing is less specific than nucleic acid testing, and even occasionally false positives may occur, antigen testing can still help identify the vast majority of people at risk during the acute infection phase in large outbreaks.

According to Hong Kong Wen Wei Po, as of 00:00 on March 14, there were 26,908 new confirmed cases in Hong Kong, of which 12,040 were confirmed by nucleic acid testing, and 14,868 were effective confirmed cases reported by rapid antigen testing. In other words, more than 50% of the new daily cases in Hong Kong today are detected by antigen rapid testing.

Eight points of health news learned that the recent launch of domestic antigen testing may be a reference to the lessons learned from Hong Kong's epidemic prevention and control work.

What can antigen self-test bring to China's fight against the epidemic?

The application plan released on March 10 clarified that antigen testing is to further improve the "early detection" ability, and made more cautious restrictions on the use scenarios of people, quarantined people and community residents who go to primary medical and health institutions within 5 days of symptoms.

Under the framework of nucleic acid testing as the golden standard for diagnosis, the common interpretation at that time was that "the mouth will not be too large".

However, in the past five days, whether it is the popularity of antigen self-test applications at the grassroots level and the people, or the encouragement of policy makers, they have far exceeded the initial idea.

Whether it is Jilin, which is in the outbreak stage of the epidemic, or some areas such as Hangzhou, free self-test kits are being distributed for early screening.

Large pharmacies, circulation enterprises, and Internet platforms have also followed up with shops. Yesterday, Tianjin Pharmaceutical Collection and Mining Center issued a document to carry out antigen detection reagent information maintenance;

Whether it is price or channel, after the approval and supply capacity constraint period, the accessibility of self-test reagents will be greatly improved.

On March 12, Vice Premier Sun Chunlan pointed out at a national teleconference held by the joint prevention and control mechanism of the State Council that it is necessary to "promote the monitoring model of 'antigen screening and nucleic acid diagnosis', and the masses can purchase tests by themselves ... Improve the sensitivity of monitoring and early warning".

To some extent, antigen detection has been compared with nucleic acid testing, and it is expected that it will play a more important role in China's anti-epidemic system.

But the broad and in-depth application of a new technology is fraught with uncertainty.

Virologist Chang Rongshan told Eight Points Jianwen, "The use of self-test in the new crown epidemic area and the blind area of nucleic acid detection can supplement the shortcomings of nucleic acid detection, but what needs to be seen is that in the domestic infection rate is much less than 1%, how to use the antigen rapid card, how to play the effect of prevention and control?" The fast check card used by medical institutions was approved at the end of 2020, but due to false positives and other problems, it was first abandoned; now the approval of self-testing is only a few days, it is already chaotic, I am worried, a chaotic situation, the next is, a card will die. Such a good thing, it was born 2 years ago, and now it is hard to have the opportunity to show its skills, hoping that all sectors of society will cherish and cherish it. ”

Some insiders expressed concern that antigen self-testing in China, where the overall prevalence rate is low, may have an effect that cannot meet the current enthusiasm and expectations.

A WHO document mentions that when the COVID-19 prevalence rate in the community is 1% (as is the case in most parts of China), even if the antigen test with a specificity of 99% is true, the positive predictive value is poor because half of all positive results are false positives.

A dealer of an approved manufacturer is worried that in the current situation of short supply and high application enthusiasm, the influx of unqualified products into the market or unreasonable abuse will bring a devastating blow to the development of the industry.

When the highly hidden Aomi Kerong penetrates the existing monitoring system and strongly opens the second half, when the antigen self-test as a patch enters the homes of ordinary people, we actually usher in a new beginning of an epidemic prevention change - it gives the grass-roots level and even ordinary people a certain right to dispose of it on the basis of the original prevention and control system.

In the face of a new technology with great potential, from scientific strategies to terminal use, from the original epidemic prevention participants to the grassroots, the public and other new entrants, everyone related to the new crown needs to think about how to be inclusive, cautious and maximize the use of this long-lost new tool to provide new ideas for epidemic prevention in the second half.

Yan Yucheng, Yu Huanhuan, Shi Chenjin | writing

Li Shanshan | responsible editor

This article was first published on the WeChat public account "Eight Points Health" (ID: HealthInsight)

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