China News Service, March 31. The National Health and Medical Commission released the "Questions and Answers on Prevention and Control of Asymptomatic Infections of New Coronaviruses" on its official website on the 31st. According to reports, as of 20:00 on March 30, there were 1,541 asymptomatic infections under medical observation, of which 205 were imported from abroad. Based on the current surveillance and research, asymptomatic infection is contagious, but the duration of infection, the degree of infectivity, and the mode of transmission need to be further scientifically studied.
Asymptomatic infection of New Coronavirus (hereinafter referred to as asymptomatic infection) refers to those who have no relevant clinical symptoms, such as fever, cough, sore throat, and other symptoms and signs that are self-perceivable or clinically identifiable. Positive people.
Asymptomatic infection can be divided into two situations: one is that the infected person has a positive nucleic acid test, and after 14 days of incubation period, there are no symptoms or signs that can be perceived or clinically recognized, and they are always asymptomatic; The nucleic acid test of the infected person was positive, and there were no self-perceptible or clinically identifiable symptoms and signs at the time of sampling, but then there was some clinical manifestation, that is, a state of "asymptomatic infection" in the incubation period.
Regarding the requirements for the prevention and control of asymptomatic infection, the National Health and Medical Commission released the new Coronavirus asymptomatic infection prevention and control management in the "Pneumonia Prevention and Control Plan for New Coronavirus Infection" (third edition) released on January 28. In the subsequent revision process, clear and specific requirements were put forward for the reporting and management of asymptomatic infection. All types of medical and health institutions at all levels find asymptomatic infections, and should report directly to the network within 2 hours.
At the county (district) level, the disease control agency completed the case investigation within 24 hours after receiving the report of asymptomatic infection, and conducted close contact registration in a timely manner, and timely reported the case questionnaire or investigation report through the infectious disease report management information system. People with asymptomatic infection should be quarantined for 14 days. In principle, those who have been quarantined for 14 days and have two consecutive negative nucleic acid tests (sampling interval at least 24 hours) can be released from isolation. If the nucleic acid test is still positive, continue to quarantine medicine. Observed. If clinical manifestations occur during isolation medical observation, they should be promptly referred to confirmed cases for standardized treatment. Close contacts of asymptomatic infection are also required for 14 days of centralized isolation medical observation.
How can people with asymptomatic infection be found? How many cases of asymptomatic infection have been found in China so far? As mentioned in the question and answer, currently, asymptomatic infection is actively detected mainly through the following methods: first, active detection during medical observation of close contacts of new coronavirus pneumonia cases; and second, active detection during cluster epidemic investigation The third is to actively detect the exposed population during the tracking of the source of infection of new coronavirus pneumonia cases; the fourth is to carry out the active detection of some travel history and residence history personnel in areas with continuous transmission of new coronavirus pneumonia cases at home and abroad.
As of 24:00 on March 30, 2020, there were 1,541 asymptomatic infections under medical observation, of which 205 were imported overseas.
Is asymptomatic infection infectious? According to the question and answer, according to the surveillance data of close contacts carried out by the country and some provinces, there are second-generation cases of close contacts of asymptomatic infections, and epidemiological investigations found that individual clustered outbreaks caused by asymptomatic infections Studies with small sample sizes have shown that viral load in respiratory tract samples from asymptomatic infections is not much different from confirmed cases.
Based on the current surveillance and research, asymptomatic infection is contagious, but the duration of infection, the degree of infectivity, and the mode of transmission need to be further scientifically studied. Some experts believe that in view of asymptomatic infection, respiratory nucleic acid specimens can detect pathogenic nucleic acids, but because there are no clinical symptoms such as coughing and sneezing, the chance of pathogens excreting from the body to cause transmission is relatively less than that of confirmed cases.
For the risk assessment of asymptomatic infection and its prevention and control, the answer is clear, asymptomatic infection is at risk of transmission. The first is the hidden nature of transmission. Asymptomatic infected people do not have any obvious symptoms and signs, it is difficult to find in the population, and the transmission caused by it is difficult to prevent. The second is the subjectivity of symptoms. People with mild or atypical symptoms may think that they are not infected with the new crown virus and do not take the initiative to go to a medical institution for treatment, which is difficult to be found in daily diagnosis and treatment. The third is the limitations of discovery. Due to the detection window period, it is difficult to find all asymptomatic infections by nucleic acid testing and serological testing methods. The existing asymptomatic infections are mainly actively screened by close contacts of the case, investigation of the source of infection, aggregated epidemic investigation and Active detection of personnel in high-risk areas has found that some asymptomatic infections are difficult to detect.
To this end, it is necessary to highlight the monitoring of asymptomatic infections, increase the screening efforts in a targeted manner, and expand the detection scope to close contacts, key areas and key populations of cases and asymptomatic infections that have been found. Once asymptomatic infections are found, strict isolation and medical observation should be strictly implemented in accordance with the requirements of the “Four Mornings”, and isolation medical observation should also be implemented for close contacts.
As some asymptomatic infections are always asymptomatic, the actual prevention and control cannot take the detection and isolation of asymptomatic infections as the leading measure. Therefore, the National Health Commission will continue to focus on the timely detection and isolation of diagnosed patients and the management of close contacts. China's experience shows that the timely detection and isolation of confirmed cases, and appropriate measures to reduce interpersonal contact can basically stop the spread of the epidemic.
How to prevent and control the asymptomatic infection in the next step? In the question and answer, the first point is to improve the prevention and treatment program. Quickly take a certain proportion of samples in key areas of the epidemic, carry out investigations and epidemiological analysis of asymptomatic infections, improve prevention and control measures, revise and improve prevention and control programs and diagnosis and treatment programs, and scientifically respond to the infection risks brought by asymptomatic infections and curb May form new outbreaks.
The second is to increase screening and monitoring. Targeted efforts were made to increase screening and expand the scope of testing to close contacts, key areas and key populations of cases and cases with asymptomatic infection. Combined with the actual situation of resuming work and resuming production, we will strengthen the monitoring of key cities, key populations, and key places to discover hidden dangers to the greatest extent. Do a good job of preventing cross-border input and output of epidemics, and conduct nucleic acid testing on all immigrants. After asymptomatic infection is found, an epidemiological investigation is conducted in a timely manner, the source is identified, and the information is released transparently.
The third is to strengthen management and treatment. Once asymptomatic infection is found, strict isolation and medical management must be strictly implemented in accordance with the requirements of the "Four Morning", and close medical contacts should also be implemented for isolation. Symptoms occurred during quarantine and immediately transferred to designated medical institutions for treatment.
The fourth is to strengthen group defense and control. Adhere to the combination of group and specialists, increase the spread of scientific knowledge on epidemic prevention, guide the public in scientific protection, conduct extensive training, and improve the prevention and control capabilities and levels of grass-roots disease control personnel, medical personnel, and community workers. From April 1st, the reports, outcomes and management of asymptomatic infected persons will be published in the epidemic notification, and timely response to social concerns.
How to do personal protection? Questions and answers suggest that the public should strengthen self-protection and awareness of health and civilization, strengthen environmental hygiene and personal hygiene protection, develop hand washing, wear face masks, pay attention to hand hygiene, one meter noodles, window ventilation, cleaning and disinfection, meal sharing system, and reduction in illness Go to places where people gather and wear scientific masks for healthy living behaviors. It is necessary to carry out a patriotic health campaign extensively, and spread the health knowledge to each family and individual in the concept of protecting themselves and the health of others, forming good sanitary habits and a civilized and healthy, green and environmentally friendly lifestyle, and improving mental health. And health literacy levels.
If you do not need to panic after a positive nucleic acid test, you should actively cooperate with medical and health institutions to do health monitoring and isolate medical observations, report in time after symptoms such as fever and cough, and accept medical institutions for standardized diagnosis and treatment.