Why do I test positive after multiple negative nucleic acids? Wu Fan talked about the "incubation period" and Shanghai's countermeasures

The Paper's reporter Li Jiawei

In the previous rounds of screening, the nucleic acid test results of relevant personnel were negative, how did new cases have been found in the new round of testing?

At 09:30 a.m. on August 25, the press conference on the prevention and control of the epidemic in Shanghai invited Wu Jinglei, director of the Municipal Health Commission, Ni Minjing, deputy director of the Municipal Education Commission, and Wu Fan, member of the Municipal Public Health Expert Group for Epidemic Prevention and Control and vice president of the Shanghai Medical College of Fudan University, to introduce the situation.

Wu Fan said that the two cases just reported were diagnosed from close contacts of this epidemic. After they were judged to be close contacts, they had already implemented closed isolation management for the first time, and during the isolation period, a case was 2 times negative for nucleic acid, and then the symptoms were found after screening.

In another case, the first 3 nucleic acid tests were negative, and the positive nucleic acid test after the 4th nucleic acid test was also found during the screening process. We have noticed a feature that the two positive cases occurred within 7 days of the onset of the disease, and when we found that the case was already in complete closed-loop management, there was no contact with society, and his close connection was actually managed. The current practice is to manage the close contacts at the first time, and at the same time manage the close connections, eliminating the risk of the possible spread of the epidemic to the outside world.

Everyone is confused why so many times nucleic acid negatives have emerged positive again? In fact, this is very in line with the characteristics of the spread of the new crown virus, whether it is the World Health Organization, our country's new crown virus pneumonia diagnosis and treatment plan or the situation in the world around the world, it is in line with this feature, that is, the incubation period of new crown pneumonia is generally 1-14 days, and most infected people will show symptoms in about 3-7 days.

That is to say, if a person is exposed to the virus and gets infected, he does not immediately show the state of onset, because each person's individual situation is different, everyone's immunity is different, and when the virus enters the body will begin to replicate is also uncertain, so we call this time the "incubation period", that is, 1-14 days. The vast majority of people may show symptoms in about 3-7 days, but they can be ruled out before the symptoms appear, which is why we will close the loop management of all the close contacts and close connections that are determined to be close contacts and close contacts at the first time.

Because of this individual difference, in the prevention and control work, the first few nucleic acid tests were negative, but then showed positive, which is also the importance of our isolation management of close contacts and close connections, we can also see this situation from other regions in China, shanghai last year's epidemic also had such a situation, which is a very consistent with the law.

Editor-in-Charge: Gao Wen