The difference between determining secondary close contact and high screening may be just the distance of a mask?

Recently, the number of sporadic asymptomatic infections in Shanghai's local epidemic has increased, and cooperating with epidemic investigations has once again become a daily routine in citizens' lives.

A group of pictures about wearing masks are widely circulated on the Internet

Determine secondary close contact and high screening,

Maybe it’s just the distance of a mask?

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Image source: Internet

Is what the picture says true?

Experts from the Shanghai Health Promotion Center reminded citizens that a rigorous epidemic investigation team will not define close contacts and secondary close contacts based solely on whether or not a citizen wears a mask. However, standardizing the wearing of masks is indeed the most direct and important means of protection at the moment.

Shanghai reminded people in January: It is really important to wear a mask tightly!

The details of the epidemiological survey show that: after taking off the mask and drinking a sip of milk tea,

It is possible to change from a sub-close contact to a close contact

In fact, during the outbreak in Shanghai in January, the milk tea shop at No. 228 Yuyuan Road was identified as the lowest medium-risk area. At that time, there was such a saying: People who entered the milk tea shop without wearing masks, or whose masks were removed in the middle, might be identified as close contacts.

On January 15, the following message was circulated on WeChat Moments: According to the latest survey results, the CDC now uses surveillance playback when conducting epidemiological investigations. If a person is in the same space with a close contact without wearing a mask, he or she will be considered a secondary close contact and will be quarantined for 14 days; if a person is wearing a mask, he or she will be considered a high-level screening person and will be subject to 2+12 management. Basically, wearing a mask can reduce one level of management.

On January 16, Zhu Yiyi, chief physician of the Institute of Infectious Disease Prevention and Control of Shanghai Center for Disease Control and Prevention, said that masks are a very important consideration in determining close contacts and secondary close contacts.

Zhu Yiyi said: "Whether to wear a mask is a very important factor in prevention and control management and the determination of close contacts and secondary close contacts. Of course, there are other factors that will be combined at the scene. Each case is the result of a comprehensive determination, and it is not that simple. It is very necessary to persuade everyone to wear a mask when going to public places."

Zhu Yiyi said that the scope of the current epidemic investigation and joint investigation is mainly divided into three levels: close contacts, secondary close contacts, and peripheral risk groups (screening personnel). Among them, the determination of close contacts and secondary close contacts is based on the results of on-site epidemiological investigations, and also needs to be verified through surveillance videos, combined with information from relevant departments, and the epidemiological investigation team will make the final determination.

At the same time, Shanghai Release also responded in the comment area on January 16: According to the relevant prevention and control requirements of the country and the city, close contacts should implement 14 days of centralized isolation medical observation + 7 days of home health monitoring, and conduct nucleic acid testing at a corresponding frequency; close contacts of close contacts should implement 14 days of centralized isolation medical observation, and conduct nucleic acid testing at a corresponding frequency; screening personnel should implement corresponding control measures and nucleic acid testing according to different situations.

"For close contacts, secondary close contacts and risk personnel, the on-site epidemiological investigation personnel conduct professional assessments based on the circumstances at the time of contact and the risk of infection." Zhu Yiyi explained that confirmed cases and asymptomatic infections were found among the employees of the milk tea shop at No. 228 Yuyuan Road, and people who entered the milk tea shop without wearing masks or whose masks were removed midway may be judged as close contacts.

"Some people walked into the milk tea shop to order drinks and took off their masks while waiting. Some customers took the hot drinks freshly prepared by the clerk in the store and couldn't wait to take off their masks and take a sip. When checking the surveillance, the epidemic investigation personnel discovered this kind of unprotected and close contact. According to the judgment standards of the relevant national and Shanghai plans, such people will be judged as close contacts. The milk tea shop staff also need to wear masks properly throughout their working hours in the store." Zhu Yiyi said that whether it is consumers or milk tea shop staff, any party who fails to wear masks properly will increase the risk of subsequent infection.

Cases in Cangnan, Wenzhou strictly wear masks when going out

Greatly reduced the risk of epidemic spread

Since two cases of COVID-19 were discovered in Cangnan County on the morning of March 3, Wenzhou has had no new confirmed cases so far.

During this round of epidemic, Cangnan conducted three consecutive rounds of nucleic acid screening on close contacts, secondary close contacts and other high-risk groups. Lingxi Town also conducted three rounds of large-scale nucleic acid screening for the population, and the results were all negative.

On March 6, two confirmed patients with COVID-19 in Cangnan who were isolated and treated in Wenzhou Sixth People's Hospital said in an interview with reporters that they both had the habit of wearing masks.

Patient Wu said that he was used to wearing a mask in public places and usually wore a mask at work. If he did not wear a mask at work, the company security would urge him to do so. On February 23 and March 2, he wore a mask during his visits to Cangnan County Hospital of Traditional Chinese Medicine. Patient Xu said that she usually wore a mask when she went out to crowded places and wore a mask during her visit on March 2. When dining at work, she would eat alone and not gather.

Zheng Yunzheng, deputy director of the Wenzhou Prevention and Control Office, believes that the key to the rapid and effective handling of this epidemic is, on the one hand, early detection and quick response, and coordinated command between the province and the city, which seized the initiative to win; another factor is also very important. During the epidemiological investigation, it was found that both confirmed cases and local people had implemented personal protective measures such as wearing masks and maintaining a social distance of 1 meter, which effectively reduced the risk of the spread of the epidemic.

Zheng Yunzheng analyzed the most noteworthy detail of the Cangnan epidemic: Case 2 felt unwell and had a cough a few days before being diagnosed. When going out, Case 2 was able to strictly wear a mask. "It is this detail that greatly reduces the risk of epidemic transmission."

From the fact that confirmed cases were able to put on masks at the first time without knowing their illness, and the epidemiological investigation found that most people in public places where confirmed cases had been were wearing masks, it can be seen that the public's awareness of scientific protection literacy has been significantly improved, and citizens are able to take the initiative to strengthen their self-protection.

"This is a critical point for the overall epidemic prevention and control." Zheng Yunzheng explained that research by medical experts has shown that in public places, if one person wears a mask and the other does not, there is a 5% risk of infection; if both people wear masks, the risk of infection drops to 1.5%; but if both people wear masks and maintain a social distance of 1 meter, the risk of infection will drop to 0.

In addition, the two confirmed cases had relatively simple trajectories and did not engage in group social activities, which also greatly reduced the risk of the spread of the epidemic.

How to wear a mask properly?

First, let's talk about how to wear a mask. When wearing a mask, you should remember to clean your hands, identify the front and back, and close it tightly. The mask should not only cover the "mouth", but also cover the mouth, nose and chin. Adjust the tightness of the nose clip and tie according to the shape of the nose bridge to ensure a tight fit. When taking off a mask that has been worn for a long time, you should not touch the front of the mask that may be contaminated, but carefully remove the tie, and then clean your hands promptly and thoroughly. Only by standardizing the wearing and removal of the mask can the mask really work.

Secondly, wear a mask at all times. Whether you are gathering with friends and family or meeting strangers, we should wear a mask when there are dense crowds and poor air circulation indoors. This is especially true in public places with complex sources of people. Even for a short time, we may come into contact with the virus when taking public transportation, taking elevators, shopping in shopping malls, or receiving express deliveries.

Third, masks come first. Although wearing a mask can cause inconveniences such as fogging up glasses, messing up makeup, and poor speech clarity, in the face of the epidemic, resisting the virus is the top priority. Please also pay more attention to children and the elderly, and always remind them to overcome minor discomforts and use masks to create a greater sense of security.

Fourth, masks also have an expiration date. Once the mask becomes dirty, deformed, damaged, or has an odor, we need to replace it in time. Do not use water or alcohol to clean it, and do not wear it continuously for more than 8 hours. No matter how strong the "safety wall" is, it will fail.

With the frequent occurrence of respiratory diseases and COVID-19 in spring, citizens should keep in mind the "three-piece set and five more". Developing the habit of wearing a mask when going out during the epidemic is not only to protect yourself, but also to protect others, which can effectively reduce the probability of infection.

It is recommended that individuals carry masks with them and actively wear masks in different scenarios such as traveling, going to work, shopping in stores, and going to public enclosed places.

Source: Science Popularization China WeChat Official Account

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