Since mid-March, the current round of the epidemic has lasted for almost a month, but fortunately, the number of confirmed cases is also gradually declining, and it seems that an inflection point can be seen.
Compared with the new local cases in the past, this round of epidemic has also brought a lot of new doubts to everyone:
Why are more and more asymptomatic infections in this round of the epidemic?
In fact, as early as April 1, 2020, the situation of asymptomatic infections was subsequently included in the daily outbreak notification.
In this round of Shanghai epidemic, the number of asymptomatic infections has increased a lot, and the number of new asymptomatic infections has even reached tens of thousands for several consecutive days.
Some people will say, are asymptomatic infected people at risk of infection? With the arrival of a new wave of epidemics and asymptomatic infections, don’t we need to worry about the life-threatening threat of the new coronavirus?
Asymptomatic infection, what is the situation?
As the name implies, it can be seen from the literal meaning that the so-called asymptomatic infection refers to the absence of obvious clinical manifestations, such as fever, fatigue, pneumonia Wait, the patient who tested positive for viral nucleic acid at that time.
According to the official explanation of the National Health Commission, asymptomatic infections are mainly divided into two types:
One is that after a 14-day incubation period observation, patients with no obvious discomfort or symptoms but a positive nucleic acid test are always in a state of asymptomatic infection.
However, this is also known as “stealth infection”, and the cause of its occurrence has not been clearly studied. Characteristic analysis shows that the virulence of the virus is much weaker than the previous original strain, so the damage to tissue cells is not obvious.
Of course, this “recessive infection” is not only owned by the new coronavirus, and most diseases caused by viruses and bacteria may be “recessive”.
The other type is a patient who has no symptoms for a while but becomes ill later on.
Because the incubation period of the new coronavirus is usually 1-14 days, during this incubation period, the patient may not have obvious symptoms, and the disease has not been detected at the time of testing.
Asymptomatic infections are increasing, can we not be too nervous?
As soon as many people see the increase in asymptomatic infections, they feel that the lethality of the new coronavirus has weakened, and the mortality rate has also decreased. Most patients have basically no symptoms, and there is no need to be too nervous.
Actually, not really.
The increase in asymptomatic infections is due to some specific mutations reducing the pathogenicity of the virus and increasing the ability of the virus to infect cells.
On the other hand, the popularization of nucleic acid testing and the improvement of testing efficiency, so as to find more hidden asymptomatic infections, and to find the stage of infection earlier before symptoms appear.
Why are asymptomatic infections increasing in this round of epidemics?
In the current round of the epidemic in Shanghai, the reason for the high number of asymptomatic infections is mainly because the Omicron variant itself is less powerful and spreads more vigorously. , the intergenerational interval of transmission is very short, about 3 days to transmit a generation.
In addition, coupled with the widespread vaccination of the society, the human body has also formed a strong resistance. Although it cannot completely prevent infection, it can reduce the disease after infection, and even Asymptomatic.
For this reason, the increase in the proportion of asymptomatic infections also makes epidemic prevention and control more difficult. Once the speed is slow or omitted, the virus may grow exponentially.
In the face of asymptomatic infection, how to isolate? What should we do in the face of asymptomatic infections?
Don’t worry, a picture will show you:
References:
【1】Wu Zunyou. The role of asymptomatic infection of novel coronavirus pneumonia in the spread of the epidemic and prevention and control strategies [J]. Chinese Journal of Epidemiology, 2020, 41(6) : 801-805
[2] Hayward, Andrew C, et al., “Comparative Community Burden and Severity of Seasonal and Pandemic Influenza: Results from an Influenza Observation Cohort Study” The Lancet Respiratory Medicine 2.6 (2014): 445-454.