How do people wear masks in schools? What are the principles for campus disinfection? Chinese CDC experts explain five details about returning to school

Beijing's senior high school and junior high school students will return to school soon. How should teachers and students protect themselves? How should people in school wear masks? What are the principles of campus disinfection? Ma Jun, director of the School Health Center of the China Centers for Disease Control, explains.

Text/Reporter Li Li Editor/Ding Lin

New Media Editor/Chen Xuanzhi

Interpretation experts:

Ma Jun (Professor at the Institute of Child and Adolescent Health, Peking University, Director of the School Health Center, Chinese Center for Disease Control and Prevention)

In recent times, the domestic epidemic prevention and control situation has continued to improve, which has created conditions for the orderly resumption of classes. On April 12, Beijing announced the time for the college entrance examination and the start of junior and senior high school. Among them, various educational institutions will give priority to organizing the start of classes for senior high school students, who will return to school on April 27; junior high school students will be ready to return to school on May 11.

After the start of the school year, the prevention and control of the epidemic in schools has become a top priority. How can we ensure the health and safety of every student and faculty member, and ensure that every school resumes classes smoothly and orderly? How can we prevent risks after children return to school? Let's see how health experts answer these questions.

Question 1: How should students choose masks in a school environment?

Ma Jun: Schools are crowded places. In order to prevent the spread of the epidemic on campus, students need to wear masks to school. But on the other hand, schools are also areas with relatively low exposure risks, so it is recommended that:

School doctors, canteen staff, doormen, cleaners, quarantine personnel, etc. wear medical surgical masks (YY0469-2011);

Faculty, staff and students wear disposable medical masks (YY/T0969-2013);

It is not recommended for children to use N95 masks (GB2626-2006);

You don't need to wear a mask at home, outdoors, or in well-ventilated places or places with low crowd density.

△Comparison of implementation standards for common masks (picture from the Internet)

It is important to note that it is not recommended for children to directly use adult masks, nor is it recommended for children to wear N95 particle protection masks. This is because children's respiratory systems are not fully developed, and protective masks have certain tightness requirements, so children will have some breathing difficulties after wearing them.

There is no corresponding standard for the selection of children's masks, but we recommend that children's masks can refer to the standards of adult masks, such as disposable medical masks and surgical medical masks. (Manufacturers) will mark what standards are met on the packaging of children's masks, and these can be used. Some children's masks are marked as anti-droplet, which can also be used, but cotton masks and sponge masks are not recommended.

Question 2: Can children use these "smart" modifications of various adult masks?

Recently, there are many eye-catching videos of homemade masks for children on the Internet, such as putting an adult mask on a child and cutting two small holes to expose the eyes (nicknamed "robbery masks" by netizens), or folding and sewing the two sides of an adult mask to fit the size of a child's face. Can these modified adult masks protect children?

Ma Jun: We do not recommend the use of these two measures. First, they change the airtight structural characteristics of the mask. Second, they also cause discomfort to children when they wear them.

△Medical masks may look thin, but their filtering effect is stronger than thick cotton masks (picture from the Internet)

Masks filter viruses by filtering air, thus playing a protective role. However, if we cut holes in the mask, its overall structure will be destroyed, which means that the mask will be leaking air all around. Other parents' methods of folding the mask to make it smaller do not actually guarantee the airtightness of the mask, and are also not recommended.

Question 3: During the epidemic, we encourage frequent hand washing. Why is hand washing particularly important?

Ma Jun: (Masks reduce the airborne transmission of viruses), but hands are also the main route of transmission of contact-transmitted bacteria and viruses. Regular hand washing (before and after meals, after returning from outside, and after doing housework) is a good habit.

△ Seven-step hand washing method (Photo source: Xinhuanet)

However (after the epidemic is over), if you wash your hands too much every day, and use cleaning products with antibacterial ingredients every time, and live a spotless life, you will be more likely to get sick - the internal and external environment of the human body is in a "clean" state for a long time. On the one hand, the body's normal defense system cannot be mobilized. On the other hand, the body's defense system is in a "dormant" state for a long time, which will also cause immune dysfunction, resulting in the inability to identify "invaders" or "failure to distinguish between friend and foe", causing various erroneous immune rejection, inhibition, allergies, etc.

Question 4: What should students pay attention to?

Ma Jun: After the school notifies us of the start date, we should observe ourselves to see if we have any suspicious symptoms of COVID-19, such as fever, fatigue, cough, etc. If we have these symptoms, students should rest at home or seek medical treatment locally. If we do not have these symptoms, we can arrange to travel back to school normally.

On the way back to school, you must take protective measures, wear a mask throughout the journey, and it is best to wear gloves, avoid direct contact with public items or places that people come into contact with, and cooperate with temperature testing.

If you have suspicious symptoms on the way back to school, you should wear a medical surgical mask or an N95 mask (to prevent infection of others). According to the symptoms, see if you need to seek medical attention in time. Of course, while we pay attention to ourselves, we should also pay attention to whether people around us have suspicious symptoms - if so, we should protect ourselves and report it in time.

In daily life and study after returning to school, you should pay attention to reducing meeting and contact with others. You should also avoid participating in group activities such as gatherings and pay attention to personal hygiene protection. In addition, you should monitor your body temperature and pay attention to any suspected symptoms. You should keep a certain distance from others when dining and studying.

Judging from the current epidemic prevention and control situation, students should also wear masks throughout their return to school, especially during classes in the classroom. Because COVID-19 has a very big feature - asymptomatic infection. Therefore, when you don't know who is sick, wearing a mask is the best protection for yourself and others.

Question 5: How to use disinfectants correctly on campus?

At the Beijing epidemic prevention and control work press conference, Beijing Municipal Education Commission spokesperson Li Yi said that after school starts, there are clear standards for the number of times public areas, tableware and classrooms should be disinfected, as well as the proportion of disinfectants. "All disinfection has a basis, not based on feelings." What are the specific standards for disinfectants?

Ma Jun: Disinfectants are essential for epidemic control. For example, chlorine-containing disinfectants with an effective chlorine concentration of 500 mg/L are currently the most commonly used, especially in schools. However, this type of disinfectant (such as 84 disinfectant, disinfectant powder, chlorine-containing effervescent tablets, etc.) must be prepared before use, and the preparation must be in accordance with the instructions.

Chlorine-containing disinfectants with an effective chlorine concentration of 500 mg/L are mainly used in public places, on the surfaces of general objects in the home, as well as for disinfection of medical waste and fabrics.

Chlorine-containing disinfectants are very irritating, so when preparing them for use, the concentration should not be too high. In addition, the disinfectant must be used within 24 hours after preparation.

In addition, chlorine-containing disinfectants are not used for air disinfection, or disinfection of hands, skin, and mucous membranes. The surfaces of general objects we are talking about mainly refer to the surfaces of our daily necessities, such as school desks and chairs, household sanitary ware, door handles, stair handrails, or children's toys.

The second commonly used disinfectant is hypochlorous acid. If hypochlorous acid is marked as 500mg/L or 100mg/L, it does not need to be diluted and can be used directly. In addition to the scope of use of other chlorine-containing disinfectants, hypochlorous acid is characterized by weak corrosiveness and no irritating odor, so it can be sprayed to disinfect the air, or to disinfect hands, skin, and mucous membranes. In addition, indoor air can also be disinfected by ultraviolet light.

The third one is 75% ethanol, which is what we often call medical alcohol. Alcohol can only be used for wiping disinfection, but not for spray disinfection, because alcohol spray is prone to fire. For hand disinfection, we also do not recommend (frequently) using alcohol, because it is harmful to the skin. By the way, alcohol cannot kill viruses without envelopes, especially norovirus, which cannot be killed by alcohol.

(The content of this article comes from the Capital Science Lecture Hall "Guidelines for Children and Adolescents' Health and Return to School during the Epidemic")

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