Is asymptomatic infection of the coronavirus contagious? Q & A

Translatiion from Chinese Google Translate

Q: What is the asymptomatic infection of the new coronavirus?

A: 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. Those who tested positive. 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.

Q: What are the requirements for the prevention and control of asymptomatic infection of new coronavirus in China?

A: The National Health and Health Commission released the "Pneumonitis Prevention and Control Plan for the New Coronavirus Infection" (Third Edition) on January 28. The asymptomatic infection of the new coronavirus was included in the prevention and control management. During the subsequent revision process, Clear and specific requirements have been set for the reporting and management of asymptomatic infections. 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. In principle, those who have been quarantined for 14 days and have two consecutive negative nucleic acid tests (sampling interval of at least 24 hours) can be released from quarantine; 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.

Q: How can people with asymptomatic infection be found? How many cases of asymptomatic infection have been found in China so far?

A: At present, we mainly actively find asymptomatic infections through the following methods: first, active detection during medical observation of close contacts of new cases of coronavirus pneumonia; second, active detection during clustered epidemic investigation; third, Actively detect the exposed population during the tracking of the source of infection of new coronavirus pneumonia cases. Fourth, carry out active detection of some travel history and residence history personnel in areas where domestic and foreign new coronavirus pneumonia cases continue to spread.

As of 24:00 on March 30, 2020, there were 1,541 asymptomatic infections under medical observation, of which 205 were imported overseas.

Q: Is the asymptomatic infected person infectious? 

A: 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 infected persons. In epidemiological investigations, it has been found that there are individual clustered outbreaks caused by asymptomatic infected persons. Sample size studies have shown that the viral load in respiratory tract samples from asymptomatic infections is not significantly different from that of 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.

Q: How to do a risk assessment and prevention of asymptomatic infection?

A: People with asymptomatic infection are at risk for 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, we will continue to focus on identifying and isolating patients in a timely manner and managing 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.

Q: How to do a good job in the prevention and control of asymptomatic infection?

A: The first is to improve the control plan. 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 them 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. 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.

Q: How to do personal protection?

A: 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, and reduce staffing when sick. Gathering places, scientific masks and other healthy lifestyle 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.


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