Why is there a large number of asymptomatic cases in this round of epidemic?
Is it contagious?
How to prevent?
Detailed explanation of Zhang Boli
Careful netizens may find that there are more asymptomatic infections than confirmed cases among the new local new coronavirus infections for several days.
Especially in the past three days, there have been many asymptomatic infections.
For example, the new data on March 25 was 1280 (confirmed cases) + 4320 (asymptomatic), the new data on March 26 was 1217 (confirmed cases) + 4333 (asymptomatic), and the new data on March 27 was 1219 (confirmed cases) + 4996 (asymptomatic).
Why do asymptomatic infections continue to appear in large numbers?
Are asymptomatic infected persons contagious?
Is it more difficult to prevent and control the increase in asymptomatic infections?
On March 28, the reporter asked Zhang Boli, an academician of the Chinese Academy of Engineering, on the above-mentioned issues.
"The large number and high proportion of asymptomatic infections are the obvious characteristics of this round of epidemics." Zhang Boli explained that this characteristic is not only related to the virus itself, but also to timely screening and early detection of infection, and is closely related to vaccination.
Asymptomatic people are mostly because of these three points
First of all, it is related to the characteristics of the Omicron variant.
"The infectivity of the new coronavirus variant is enhanced, and extremes will reverse, and its toxicity is relatively weakened." Zhang Boli explained that the clinical manifestation of the weakened virus toxicity is that the clinical symptoms will be lighter, and many infected people do not show clinical symptoms for a short time after infection.
The results of the case fatality analysis of the omykron and delta strains from other countries showed that the case fatality rate of the omykron strain decreased during the epidemic period, indicating that the omykron variant was less pathogenic than other strains. powerful.
"Nevertheless, asymptomatic people should not be taken lightly." Zhang Boli reminded: First, although asymptomatic, it is still contagious and more insidious; another is asymptomatic today, and may have symptoms tomorrow.
"Especially for key groups, such as the elderly, people with underlying diseases, as well as frail, obese, and heavy smokers, they are at risk of developing and rapidly deteriorating, and they need to pay special attention." Zhang Boli said, for the general asymptomatic The focus is on isolation and observation, and advocates the use of proprietary Chinese medicines for early intervention. One is to control their symptoms, especially not to turn into the common type; the other is to promote their nucleic acid to turn negative as soon as possible.
There are many asymptomatic people, which is also related to early screening and early detection.
"After the outbreak of the epidemic, extensive screening has been carried out in various places. Due to early detection, many patients are still in the early stage of infection and have no symptoms of infection." Zhang Boli said.
With the strengthening of early detection capabilities in various parts of my country, the goal of nucleic acid detection in my country is to complete the task of nucleic acid detection in the designated area within 24 hours.
The latest deployment of nucleic acid screening has enabled all parts of my country to detect infected persons as early as possible in a shorter period of time and control the source of infection.
Therefore, compared with those who were found in sentinel medical institutions due to fever and dry cough in the past, many infected people were found much earlier in time.
"Another important reason is that Chinese residents have been vaccinated on a large scale." Zhang Boli explained that the population's immunity is generally enhanced, so most of them are asymptomatic.
Are asymptomatic infected people contagious? How to prevent?
"In the early stage of this round of the epidemic, after some asymptomatic infections were diagnosed, there were cases where their close contacts all showed positive nucleic acid." Zhang Boli said when analyzing the Jilin epidemic that asymptomatic infections were easy to cause the hidden spread of the virus, and it was discovered that more people have been infected.
Although asymptomatic infected people have no clinical symptoms, they can detect the nucleic acid with virus in their body through nucleic acid, and they have a certain viral load and are also infectious.
Relevant experts of the joint prevention and control mechanism of the State Council said that from the perspective of epidemic prevention and control, the existence of asymptomatic infections makes it difficult to detect the epidemic, and if a large number of asymptomatic infections are not detected in time, the epidemic will further spread. It has also increased the difficulty of controlling the epidemic in a timely manner.
In this regard, Zhang Boli said that it is necessary to carry out rapid and strict traceability of the flow control. The key is to be quick, early detection and early isolation.
"The epidemic caused by this round of Omicron has been spreading for a period of time, and there are multiple routes of infection. Therefore, the flow adjustment is difficult and complicated, and it needs to be more strict and careful, not only to pay attention to the close contact, sub-close contact, and general contacts of cases, but also to It is necessary to consider whether there is a transmission chain in the early stage of the case, and try to find asymptomatic infected persons as much as possible." Zhang Boli said that only by finding all asymptomatic infected persons in the shortest time and completely blocking community transmission can the social face be cleared as soon as possible.
Zhang Jiaxing/Science and Technology Daily