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What does asymptomatic infection mean? What is the source of asymptomatic infection

What does asymptomatic infection mean? What is the source of asymptomatic infection

Novel coronavirus pneumonia have a fever of symptoms, such as fever, cough, dyspnea and so on. But respiratory tract specimens are positive for COVID-19 etiology. The biggest feature of this group of patients is that they are both new crown pneumonia and COVID-19 disseminators. CCTV has pointed out whether the symptoms of patients are related to the virulence of viruses and human immunity. When COVID-19 has an asymptomatic host (patient), it will infect others when it contacts other people.

In fact, during novel coronavirus pneumonia outbreak, the discussion about asymptomatic infections is never stopped. Before April 1, China did not publish the number of asymptomatic infections.

The novel coronavirus pneumonia grandpa grandpa Ceng Yixin, deputy director of the national health and Health Committee, said at a press conference in February 14th that according to the relevant regulations, only new suspected cases and confirmed cases of new crown pneumonia were announced. Asymptomatic infections were not cases and need not be announced. The novel coronavirus pneumonia was confirmed as a new confirmed case of pneumonia when asymptomatic infection appeared.

Zeng Yixin said at the press conference that there are four main sources of asymptomatic infection:

Close contacts of novel coronavirus pneumonia cases have found some such people in medical observation period.

In the investigation of aggregated epidemic situation, we may find asymptomatic infected persons in the process of some active detection;

When novel coronavirus pneumonia cases were traced, the asymptomatic infection could be detected when the exposed population was actively tested.

When novel coronavirus pneumonia cases are detected, and active travel time and residence history of the people in the area of continuous transmission are detected, asymptomatic infections may be found. Asymptomatic infected persons are not included in the daily report, but if asymptomatic infected persons have symptoms during centralized isolation, they will be classified as confirmed cases and reported.

At that time, the CDC listed three conditions for identifying asymptomatic infections as sources of infection. Once these three conditions were met, they would be strictly segregated (refer to New Coronavirus pneumonia epidemiology survey Guide).

The asymptomatic infected person had a clear contact history with the second generation case, and the second generation case had no contact history with the asymptomatic infected person after onset;

The second generation cases developed 1 to 14 days after the last contact with asymptomatic infected persons;

The asymptomatic infected persons had suspected exposure history such as travel or residence history in Wuhan and surrounding areas or other communities with case reports within 14 days before the onset of the disease. The second generation cases had no other relevant exposure or exposure history except the first case.