Five COVID-19 antigen self-testing products officially launched!Zhang Wenhong, Hu Bijie, eight problems in detail

2022-04-24 0 By

On March 12, the STATE Food and Drug Administration (SDA) issued a notice approving the change of application for self-testing of COVID-19 antigen products by Nanjing Novizan, Beijing Goldwolf, Shenzhen Huada Yinyuan, Guangzhou Wanfu Bio and Beijing Huacotai Bio.Since then, five COVID-19 antigen self-testing products have been officially launched.The Comprehensive Team of the Joint Prevention and Control Mechanism of The State Council on COVID-19 officially released the Novel Coronavirus Antigen Testing Application Protocol (Trial), which is undoubtedly a bombshell news for the current fight against COVID-19.Professor Zhang Wenhong, director of the National Medical Center for Infectious Diseases, director of the Department of Infectious Diseases of Huashan Hospital and Professor Hu Bijie, director of the department of infectious Diseases of Zhongshan Hospital answered the questions that people care about.What is the difference between antigen testing and nucleic acid testing?Hu Bijie: The principle of antigen detection and nucleic acid detection is different.To put it simply, the nucleic acid test for COVID-19 applies the principles of molecular biology. By reverse transcription, amplification and quantitative detection of the nucleic acid sequence of the pathogen, the virus detection has high sensitivity, specificity and cost.Using immunological principles, antigen detection can be completed quickly in a non-laboratory environment, and the detection sensitivity and specificity are worse than nucleic acid detection.Therefore, antigen testing will be a supplement to COVID-19 testing, but cannot replace nucleic acid testing.Antigen tests are performed using nasal swabs.To be specific, wash your hands, blow off your nose, and remove a nasal swab like the one now used in nucleic acid tests, gently and without breaking it.Tilt your head slightly back and rotate it deep into the nostril four times (about 15 seconds). Repeat with the other nostril.The nasal swab is then placed in the reagent tube and the results can be seen after about 15-20 minutes.Minors were sampled by other adults.What are the benefits of increasing antigen testing?Hubbij: It’s a good thing that you can sample under simple conditions.Both primary medical institutions without nucleic acid testing capacity and community residents can self-test.Antigen detection as a supplementary means can be used for population screening, it is very convenient to use, can be tested at any time, fast reporting.Is the antigen test accurate?Zhang Wenhong: Sensitivity is slightly worse than nucleic acid detection.Nucleic acid tests, which are more accurate than nucleic acid tests, are still the basis for confirming novel coronavirus infection.At the time of initial infection, the amount of virus is so low that nucleic acid tests may detect it, because nucleic acid tests have an amplification process, while antigen tests may not detect it at this time.For example, nucleic acid test kits currently used in China have a sensitivity of about 75 percent compared with antigen tests.But because omicron replicates so quickly, it may be the next day that viral levels rise to levels detectable by antigen.So you can test them at home for several days, and if they don’t, then the risk of infection is very low.What is the significance of antigen testing in fighting epidemics?Zhang Wenhong: Although nucleic acid test is more accurate, antigen test is used as a supplementary means for screening. If it is positive, it can basically confirm the diagnosis. But if it is negative, it can also improve the sensitivity and positive rate by taking more tests, or it can be confirmed by nucleic acid test.However, due to the convenience, it can be tested without going to the hospital and when nucleic acid resources are not sufficient, so that more people can easily detect whether there is a virus infection at an early stage. Once detected, it can be diagnosed, which is conducive to improving the ability of “early detection”.Who is antigen testing suitable for?Zhang Wenhong: Quarantine observers can pass the antigen test. If the antigen test is positive, there is no need for nucleic acid test.If the antigen test is negative for several days in a row, the risk of infection is low.People who are quarantined at home or suspect that they are at risk of infection can take a self-antigen test. Once the antigen test is positive, they should immediately report to the relevant authorities.Nucleic acid tests are usually performed to confirm this.Is antigen testing appropriate for asymptomatic infected persons?Zhang Wenhong: Currently, there are many asymptomatic patients infected with Omicron.Asymptomatic carriers are difficult to detect without nucleic acid testing, but this does not mean that asymptomatic carriers are less infectious.Asymptomatic infected people also carry the same amount of virus as those with significant symptoms.On the other hand, asymptomatic infected people are more likely to cause large-scale infection unconsciously because they do not know they are infected.At the present stage, nucleic acid screening should be intensified to screen asymptomatic infected persons under the prevention and control principle of pursuing social elimination.When nucleic acid collection is not convenient and resources are insufficient, antigen detection is a good supplement.You can take a self-test at home, and immediately report to the relevant authorities if you are positive. This will help us find the infected person faster and isolate them, and accelerate the realization of social zero elimination.When does an antigen test work?Hubbij: There’s a lot of buzz about home antigen testing kits.However, at the present stage, China still adheres to the principle of “early detection, early reporting, early isolation and early treatment”, and also pursues “early” in the management and control of asymptomatic infected persons.Antigen testing is useful for screening highly infectious COVID-19 patients with a high viral load.At the technical level of epidemic prevention and control, the more measures and means are definitely the better. Antigen detection has its own advantages, but how to implement it still needs to be further clarified.I believe that in the near future, this antigen detection kit will go into ordinary people, we can also timely pay attention to the national policy.Since there is no way to buy, what should citizens do when they show symptoms?Hu Bijie: At present, ordinary citizens can not buy such test boxes in the market.If you feel fever, cough and other symptoms, you should go to the fever clinic of the hospital as soon as possible.Recently, among the confirmed cases in Shanghai, there were patients who sought treatment due to illness, which also shows that fever clinics, as surveillance posts, play a key role in epidemic prevention and control.He also reminded people to wear masks at all times if they go to fever clinics, keep a distance from others, try not to drink water, put on masks immediately after the diet test, and do not talk to strangers during the visit.Can self-test Results replace Nucleic acids?Can’t.The circular makes it clear that, after studying, the Comprehensive group of the Joint prevention and control mechanism of The State Council on COVID-19 has decided to add antigen testing to nucleic acid testing.Nucleic acid tests continue to be the basis for the confirmation of novel coronavirus infection.The Novel Coronavirus Basic Requirements and Procedures for Antigen Self-Testing in the pilot protocol also stresses that antigen testing is generally used in the acute period of infection, i.e. in samples from suspected persons within 7 days of the onset of symptoms.Further nucleic acid tests should be performed on both positive and negative antigenic results of suspected persons. Positive results can be used for early triage and rapid management of suspected persons, but cannot be used as the basis for the diagnosis of Novel coronavirus infection.02 Who can test themselves?Three types of people: (1) those who go to primary medical and health institutions with respiratory and fever symptoms within 5 days;(2) Quarantine observation personnel, including home quarantine observation, close contact and sub-close contact, entry quarantine observation, containment area and control area personnel;③ Community residents with the need for antigen self-detection.03 How to determine the self-test frequency of COVID-19?It depends on the crowd.During the quarantine period, nucleic acid tests will be carried out in accordance with the current prevention and control plan, and antigen self-tests will be conducted once a day for the first five days.For community residents, those who have the need for self-testing can buy it for self-testing.Asymptomatic residents who test negative for antigen can be kept under close observation and tested for antigen or nucleic acid when necessary;Residents with symptoms are advised to go to medical institutions with fever clinics as soon as possible for nucleic acid testing;If it is inconvenient to see a doctor, they should be self-isolated at home, avoid going out and take an antigen self-test every day for 5 consecutive days.04 What are the precautions for self-test?There are three main steps in antigen self – testing.First, antigen self-test preparation 1, wash your hands.Wash hands with running water or hand sanitizer.2. Understand the testing process.Carefully read the instructions of antigen self-test reagents and related matters needing attention.3. Reagent preparation.Check whether the antigen self-test reagent is within the warranty period, and check whether the contents of nasal swabs, sample tubes and test cards are missing or damaged.If the reagent expires or its contents are missing or damaged, the reagent should be replaced in time.4. Confirm the requirements of ambient temperature and humidity.Colloidal gold strip detection is generally required at 14℃ to 30℃ under normal temperature conditions, to avoid excessive cold, overheating or humid environment resulting in abnormal test results.Remove the antigen test card and place it in a flat, clean place.1. Nasal swabs can be taken by patients over the age of 14.Self-examiners blow their noses with toilet paper first.Unpack the nasal swab carefully and avoid touching the swab tip with your hands.Then the head is slightly tilted back, and the swab is placed on one side of the nostril with one hand, and then the swab is placed on the nasal cavity and rotated at least 4 times (the retention time is not less than 15 seconds) along the bottom of the lower nasal canal. Then the same swab is applied to the other nasal cavity.2. Other adults should take samples for self-examiners aged 2-14.When sampling, blow the nose with toilet paper first, then tilt the head slightly.Sampling personnel carefully open nose Swab the outer packing, avoid hand contact with the swab head, head of the handle gently lifted by collectors, one hand holding swab stick into the side of nose and slowly along the bottom of the nasal passages under the backward at least 4 turns into 1 cm after post nasal residence time (not less than 15 seconds), then use the same swab to another nasal repeat the same operation.1. According to the reagent instructions, immediately place the nasal swab after sample collection in the sample tube. The swab head should be rotated and mixed in the preservation solution for at least 30 seconds, and at the same time, squeeze the swab head at least 5 times across the outer wall of the sample tube to ensure that the sample is fully eluded in the sample tube.2. Squeeze the liquid in the swab head dry by hand across the outer wall of the sample tube, and discard the swab.After the sample tube is covered, the liquid is dropped vertically into the sample hole of the detection card.3. Read the result after a certain time according to the reagent instructions.Positive results: both “C” and “T” showed red or purple bands, and the color of the band at “T” could be dark or light, which were all positive results.Negative results: red or purple bands were shown at “C” and no bands were shown at “T”.Invalid result: No red or purple band is shown at “C”, regardless of whether a band is shown at “T”.Invalid result, need to take a new strip test again.How to deal with the used self-testing reagent?The same goes for people.Quarantined observation personnel: No matter the test results are negative or positive, all used samples, sampling tubes, test cards, etc., shall be put into sealed bags for management personnel to handle according to medical waste or procedures.Community residents: If the test results are negative, all nasal swabs, sample tubes and test cards after use shall be put into sealed bags and disposed of as general waste;If the test results are positive, they will be transferred to medical institutions for treatment as medical waste.06 where can buy self test kit?According to the database query results and announcements of regulatory authorities, no COVID-19 antigen testing kit for self-testing has been approved in China so far, so there are no COVID-19 self-testing kits available for purchase in China.Industry analysis pointed out to reporters, the document’s self-test part is “ahead of” at present, may be the department is stepping up approval.Shortly after the release of the above trial documents, Nanjing Novozan Biotechnology Co., LTD. (Novozan, 688105) announced thatThe Novel Coronavirus antigen test kit independently developed and produced by Nanjing Novizan Medical Technology Co., LTD. (novizan Medical for short), a wholly-owned subsidiary, has recently received the Registration Certificate for Medical Devices issued by the National Medical Products Administration (Registration Certificate No. : National Instrument Note Permit 20223400346).However, Novizan’s products are still intended for use by trained personnel in biosafety and conditions, not for home testing.In addition to the newly approved Novizan test, there are four other approved COVID-19 antigen testing products, all operated by professionals, from Guangzhou Wondfo Biotech Co., Ltd., Beijing Kingwolf Bioengineering Technology Co., Ltd., Shenzhen Huada Yinyuan Pharmaceutical Technology Co., Ltd., and Beijing Huacotai Biotechnology Co., Ltd.07 How much does the self-test kit cost?As there are no approved COVID-19 self-test kits in China, the price is not yet known.However, refer to the overseas price of domestic self-test kits: At the end of 2021, Jiuan Medical mentioned in its interactive platform reply to investors that the official price of the company’s COVID-19 antigen test kit in Amazon is $6.99 per person, and currently there is no plan to sell it at a lower price.The testing reagents required for the isolation of observers are not required at their own expense.According to the trial plan, the administrative departments (such as communities, towns and villages, isolation sites, etc.) responsible for the procurement, distribution and management of antigen detection reagents for this part of the test.What are the practical uses of the test results?The NHC said antigen tests can be used as a supplementary means for screening specific populations, helping to improve “early detection” capabilities.It is not yet clear whether the self-test results of COVID-19 antigen can be used as travel vouchers, and it is still waiting for further details from relevant departments.Source: CCTV news the paper