On November 9th, Changsha CDC conducted a two-day inspection (Changsha CDC inspected).

at present, Changsha city continues to adhere to the general strategy of "external defense against input and internal defense against rebound" and the general policy of "dynamic zero clearing", and continues to carry out normalized nucleic acid testing and nucleic acid testing for key populations in a standardized and orderly manner. From October 22, 222, the city implemented the regional nucleic acid screening strategy of two-day inspection.

Maybe you will be puzzled. Why do you want to do multiple rounds of nucleic acid?

1. The persistent variation of virus presents new features

BF.7, which is the abbreviation of BA.5.2.1.7, a sub-strain of BA.5 mutant in Omicron. Compared with BA.4 or BA.5, it has the advantages of fast spread, strong infectivity and shorter intergenerational interval, which easily leads to large-scale spread. Recently, WHO also issued a warning: BF.7 is spreading around the world, "or it will become mainstream in a few weeks".

2. Nucleic acid detection is still an important means for early detection of infected people.

The intergenerational interval between p>BF.7 infected cases is shortened, and it is necessary to dynamically and repeatedly detect nucleic acids in a short period of time in order to detect them as soon as possible. Only by finding potential infected people quickly and accurately, especially asymptomatic infected people, and effectively cutting off the virus transmission chain in time can we achieve the greatest prevention and control effect with the least cost.

3. The result of nucleic acid test is "false negative"

Factors such as disease development stage, sampling and vaccination will all affect the detection of virus:

If the virus concentration in the body is not enough, it may be false negative if it is below the detection limit;

If no virus is collected in the sampling, false negative may appear;

The antibody produced by vaccination can remove the virus, and the viral load is small, which may lead to false negative;

Other physical and chemical factors affecting the stability of Covid-19 nucleic acid.

Based on the above reasons, only by adjusting the frequency of nucleic acid detection and carrying out multiple rounds of nucleic acid detection for key areas and key personnel can potential infected people be found quickly and accurately, so as to take targeted control measures in time and stop the spread of the epidemic.

It should be noted that the increase in the frequency of nucleic acid detection and the gathering of people in line also increase the potential risk of infection. When participating in nucleic acid testing, citizens should pay attention to the following points:

Before sampling: do not eat half an hour before sampling, try to choose sampling points with fewer people, wear masks regularly throughout the whole process, bring mobile phones, queue up consciously and orderly, and keep a line. You can carry a proper amount of disinfectant wipes and spare masks.

during sampling: please don't put your belongings on the sampling table, and don't touch the sampling table and the protective clothing of sampling personnel. Try to relax and reduce swallowing and throat clearing.

after sampling: put on a mask and leave immediately. Don't stay at the sampling point. Do a good job of hand hygiene in time. If you need to replace the spare mask, please throw the discarded mask into the designated medical trash can.