Since the new round of the epidemic, Shanghai has implemented high-frequency nucleic acid screening for some time. Starting from the 15th, Shanghai will carry out “antigen + nucleic acid” combined detection and screening for all personnel in the closed control area and control area, and conduct antigen detection and screening for all personnel in the prevention area; from the 18th to the 21st, the closed control area will continue to Nucleic acid testing was carried out in four days.
Why is high-frequency nucleic acid testing necessary?
How to prevent cross infection during screening?
How to make nucleic acid detection more convenient and efficient?
Coordinating the next step of resumption of work and production, how to meet the normalization needs of nucleic acid testing?
…
The reporter interviewed relevant departments and experts in Shanghai in response to the issues that citizens have focused on and reported recently.
A question: What is the significance of high-frequency nucleic acid detection screening? Why is it necessary to carry out nucleic acid testing for several consecutive days in the sealed area?
Gao Chunfang, Director of the Laboratory Center of Yueyang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, said , high-frequency nucleic acid detection is very necessary. In terms of the occurrence and development of clinical diseases, any pathogen infection has a certain incubation period, and the new coronavirus is no exception, and there are certain individual differences in the length of the incubation period. From the perspective of detection technology, there is a growth and replication process in the human body after virus infection. If the viral load in the early stage of infection is lower than the detection limit, the positive is difficult to be found. This time period is the detection window period. The “incubation period + detection window period” makes it impossible to detect positive results in the early stage of infection. Therefore, repeated tests can increase the probability of positive detection and detect positive in time.
At the same time, throat swabs, nasal swabs, and nasal + pharyngeal swabs are mainly used for sampling of respiratory pathogens. In several forms, there are inevitably some sampling differences in the sampling process. Such differences include sampling site, depth, and amount of collected secretions. Therefore, repeated sampling and testing can compensate for the possible false negative effects caused by sampling errors.
Hu Xiaobo, director of the Shanghai Clinical Laboratory Center, said that when it comes to community screening, when the community completes a round of nucleic acid After screening, usually infected persons with higher viral loads can be screened, but some infected persons with lower viral loads will show negative nucleic acid results in the early stage, and only wait until more and more viral replication in their bodies. Only then can it be discovered by inspection. The latter, if not detected in time, may become potential spreaders in the community. Therefore, it is necessary to dynamically detect positive infected persons as soon as possible through multiple rounds of nucleic acid screening in a row, and realize the dynamic clearing of social aspects as soon as possible.
Second question: How to prevent cross-infection during large-scale nucleic acid detection and screening?
Wu Qing, Member of the Standing Committee of the Shanghai Municipal Party Committee and Executive Deputy Mayor, said that in the allocation of resources for large-scale screening, In terms of utilization and dispatching organization, Shanghai has organized various streets, towns and communities to reasonably set up sampling points, and try to do a good job in organizing and mobilizing residents. , A series of organizational methods such as “downstairs that should go downstairs”, “division of buildings, time periods, and batches”. At the same time, guide residents to strictly abide by the “2-meter line” spacing, wear masks, and not communicate during the testing process to avoid cross-infection.
Professor at the School of International and Public Affairs of Shanghai Jiao Tong University and Executive Director of the Shanghai Jiao Tong University-Yale University Health Policy Joint Research Center, Zhao Dahai said that by optimizing Nucleic acid testing methods and methods, organize residents to participate in nucleic acid testing in an orderly manner in time and batches, reduce crowd gathering, and can effectively prevent cross-infection.
Three questions: How to make large-scale nucleic acid testing more convenient and efficient?
In terms of sampling power, Shanghai has required all districts to pass grid inspections to find out what is in the screening area. The number of actual population, reasonable allocation of sampling medical staff. Taking April 16 as an example, Shanghai invested nearly 25,000 sampling medical staff, including more than 12,000 medical staff from Jiangsu, Zhejiang, Anhui and other places. With the support and help of the sister provinces and cities, the large-scale nucleic acid screening has been completed on time and according to the quantity in the past few days.
In terms of detection strength, on the one hand, Shanghai has strengthened nucleic acid detection through rapid new gas membrane laboratories and mobile nucleic acid detection vehicles. On the other hand, with the coordination and help of the comprehensive team of the Joint Prevention and Control Mechanism of the State Council, Shanghai has further enhanced its testing capabilities by accepting construction assistance from other provinces and cities and sending samples to sister cities.
Currently, Shanghai has a maximum detection capacity of nearly 5 million tubes per day. At the same time, more than 2,000 sample transfer vehicles are deployed to speed up sample transfer. .
Four questions: How to meet the normalization needs of nucleic acid testing in coordinating the next step of resumption of work and production?
Wu Qing said that Shanghai is currently planning a layout based on regional population density, functional positioning, etc. The nucleic acid detection method that combines “point + convenient sampling point + mobile sampling point” to coordinate the setting of normalized sampling points.
The fixed sampling points are mainly about 200 medical institutions in Shanghai; the convenient sampling points are mainly set up in the form of “books and newsstands”; the mobile sampling points are mainly based on “breakfast” In the form of “car”, the mobility and mobility are improved by setting up sampling cabins and mobile sampling vehicles.
Fixed, convenient, mobile and other sampling point facilities will be mainly located in residential areas, transportation stations (such as subway entrances, bus stops, Airports, ports, high-speed railways, bus stations, etc.), CBD parks and other office areas, large construction sites, schools, large supermarkets, medical stores and other surrounding areas. For places with a lot of people, try to choose a relatively independent site that is open, with better ventilation conditions.