On the afternoon of March 20th, the Hanjiadun Street Comprehensive Community reported on the “Important Notice” that “there was another new case in Lishui Kangcheng District last night.” In response, relevant parties in Wuhan responded: “After investigation, the residents of the community, Zhang Moumou, were asymptomatic infected. Non-diagnosed cases. “So, what are” asymptomatic infections “and how big is the threat posed by asymptomatic infections? The reporter interviewed relevant experts on related issues.
What is asymptomatic infection?
According to the definition in the “COVID-19 Prevention and Control Plan (Sixth Edition)”, “asymptomatic infection” of COVID-19 virus refers to: asymptomatic or serum-specific IgM antibodies of COVID-19 virus without clinical symptoms, respiratory tract and other specimens Test positive. In the “COVID-19 Case Monitoring Program (Third Edition)” released on January 28, “asymptomatic infection” is distinguished from suspected cases, confirmed cases, and mild cases. If the COVID-19 virus nucleic acid is checked, Positive but without symptoms and not included in confirmed cases published daily.
Liu Youning, former director of the PLA Institute of Respiratory Diseases, said in an interview with reporters that those who have been confirmed to be “infected” but asymptomatic can be divided into two categories, one is still in the incubation period, and symptoms will occur after the incubation period, and the other is Asymptomatic from beginning to end.
Why are asymptomatic infections not included in confirmed cases?
As defined in the COVID-19 Prevention and Control Plan (Sixth Edition), suspected and confirmed cases require clinical manifestations. Asymptomatic infection patients have no clinical manifestations, and need to be isolated for 14 days and further testing is needed to make a judgment. If an asymptomatic person develops symptoms during quarantine, they are reported as a confirmed case and published.
Is a positive nucleic acid test contagious?
Both the “asymptomatic infection” and “Fuyang” patients have positive nucleic acid test results. Does it mean that the two groups are infectious? The reporter interviewed BGI on this issue and learned that a positive nucleic acid test refers to the virus’s nucleic acid found at the sampling site during the test. But the nucleic acid comes from “live virus” or “dead virus”, and the virus needs to be cultured to confirm. Liu Youning also said in an interview with reporters that a positive nucleic acid test cannot determine the concentration and activity of the virus, let alone whether it is infectious.
Liu Youning also said that the current “Fuyang” patients have antibodies in their bodies within a short period of time after they have recovered, and the virus cannot reproduce in them, so they are basically not contagious and are not suitable for inclusion in the category of asymptomatic infection.
How to find “asymptomatic infection” and how to deal with it?
According to the “COVID-19 Prevention and Control Plan (Sixth Edition)”, it is currently found mainly through close contact screening, cluster epidemic investigation, and source tracking investigation.
Liu Youning said that the current treatment of asymptomatic infection is to find and quarantine and report directly to the network within 2 hours. During the quarantine period, continue to conduct nucleic acid testing and further observe whether symptoms occur. You can also use some antiviral drugs Intervene. In principle, the quarantine can only be released after two consecutive negative nucleic acid tests.
How to tell if you are “asymptomatic”
Nowadays, the only way to confirm the diagnosis of asymptomatic infection is nucleic acid testing, but the number of nucleic acid test boxes is limited in most areas. To avoid wasting medical resources, self-diagnosis can be performed.