Dai is still not wearing, it has become an international choice problem.With the new type of coronary virus entering the world, there are significant differences in whether the public wants to wear masks.

On March 14, US President Trump announced that he entered the country's emergency state.Nevertheless, at the press conference of Trump on the same day, Anthony Middot; Fuli, an American Centers for Disease Prevention and Control Center (CDC) officials, only emphasized that the reporter's question of whether the current method of preventing and controlling the epidemic was effective, and only emphasized that he washed his hands and could not reach his hands.The crowded place did not mention wearing a mask.

The officials and media of Europe and the United States have been promoted. Only those who are sick need to wear masks. Healthy people are not only needed to wear, but also have no effect.The article released on March 15, the New York Times, stated that most surgical masks are too loose and cannot prevent virus from inhaling.The German media also emphasized that healthy people wear masks in public places to try to protect themselves from virus violations in the air, which is a waste of time.

This is significantly different from China's prevention and control experience.In the early days of epidemic prevention, the Chinese State Council's epidemic prevention and control team released a guide to pneumonia masks for new coronary virus infections to explain how different people choose masks.With the spread of the epidemic, the media took turns publicity, and the Chinese public generally wore masks.This also made the e -commerce platform cover.The Japanese public has the habit of wearing masks every day. This epidemic has become a natural thing, nor does it have controversial due to masks.

The popularity of preventing and controlling the new crown epidemic, whether the mask is useful, has become a question of many people's hearts.The European and American epidemic is continuing to spread, and the use of masks is increasingly questioned.

Under the outbreak of the new Coronatte Virus (2019-NCOV) released by the World Health Organization (WHO) on January 29, it is recommended to use masks in the community, home care and medical environment:Lack of valid evidence confirmed that wearing masks can curb infectious diseases, it is recommended that the public should not wear masks in the community environment.

But some scholars questioned this.On March 3rd, Dr. Liang Zichao of the Association of Chest and Heart Diseases in Hong Kong, etc., pointed out in the Liuye knife that lack of valid evidence should not be equivalent to invalid evidence. In the face of the new situation of COVID-19Global policy makers re -consider the value of masks.

What is the divergence of masks?

To understand whether the mask has a protective effect, it is necessary to clear the way of spreading the virus.The main way to propagate the new coronal virus is currently the airway droplets and close contact.In a relatively closed environment, if it is exposed to high -concentration of high -concentration of gas solids for a long time, there is still possibility of possibilities through gas solution.

Medically, the particle size of the air is greater than 5mu; m (MU; M is micron, 1 micron = 0.001 mm) bacteria or virus infection, which is called droplet infection.When the infected person coughs or sneezes, the diameter of the virus is greater than 5mu; m droplets, which is droplets.Drums are transmitted when the droplets are touched by the eye conjunctiva, oral or nasal mucosa of the person at close range.Most of the influenza explosion shows that droplet infection is the main method of infection.

Qi -soluble is a small or liquid point dispersed in the air, and the size is usually 100mu; M is below 100mu.The droplets discharged from cough or sneezing quickly narrowed the size by evaporated, forming a droplet core, thereby increasing the number of particles that serves as gas -soluble.The particle size of the liquid droplet core is generally below 5mu; M, bacteria or viruses and other pathogenic microorganisms are attached to it to form air -soluble gums with viruses, and then inhale the respiratory tract through air to cause infection.

Specific masks can block droplets.The reasonable choice and application article published by the Xuanwu Hospital of Capital Medical University in the Magazine of the Chinese Hospital in the Magazine of the Chinese Hospital stated that the standard medical surgical mask has three layers, and the outer layer has water resistance to prevent droplets from entering the mask.The middle layer has a filtering effect, which can block more than 90%of 5mu; m particles.The inner layer of the near -mouth nose is used to absorb moisture.

According to the above paper, there are three protection principles of masks. One is filtering. The mask material and textile method make the gap between the mask smaller than the virus volume and filter out the virus.The second is to adsorb, the static effect of the mask, and adsorb the virus on the outer layer of the mask, such as the so -called add electrostatic filter layer.The third is to kill. The mask material has a bactericidal function and directly kills the virus, such as titanium dioxide catalyst.

A summary article about the University of Toronto also stated that the medical surgical mask can be used to prevent droplet transmission, but it cannot provide reliable air -soluble gum protection.

The higher -level medical protective mask can block the smaller particles.The filtering efficiency of medical protective masks that meet the national standards of China exceeds 95%, which can block the diameter of the air transmission less than 5mu; M infection factors of M or close contact with droplets transmitted infection factors.Medical protective masks can prevent most pathogens such as bacteria and viruses used for medical staff working in high -risk areas, as well as close contact with patients.The corresponding US standard is N95 mask.

A general consensus is that specific masks can effectively prevent patients from spreading droplets and then block the transmission of viruses in the crowd. Therefore, patients who are sick should wear masks.The reasonable choice and application of the mask states that patients with respiratory infectious diseases should wear medical surgical masks to prevent their virus or bacteria from spreading to the outside world, thereby protecting the surrounding healthy people.An article published by the University of California, Professor Martin Weiss, Los Angeles, also mentioned that the medical surgical mask was used to protect the harm of pollutants caused by the wearer.

The difference is whether the healthy people are effective in wearing a mask.

According to the official website of the US Food and Drug Administration (FDA), although medical surgical masks can effectively prevent the outward splash and large particles of droplets, according to the design, the mask will not filter or prevent the air from coughing, sneezing or a certainSome small particles spread by medical procedures.In addition, the surgical mask is relatively loose and has a gap with the face, and it cannot completely prevent bacteria and other pollutants in the air.

Because the N95 mask can close the face and the protective level is higher, the article believes that only the N95 can effectively prevent the new coronary virus.However, although the protection capacity of medical surgical masks is yet to be tested, in some studies, it shows the protection effect similar to the N95 mask.In March 2019, an article published by the American CDC National Personal Protection Technology Laboratory (NPPTL) on the American Medical Association magazine (JAMA) shows that in a random trial involving 2,862 medical staff in the United States and 4 years,Wearing N95 masks and medical surgical masks outpatient medical staff, the incidence of influenza is not significantly different.

Another point of view is that keeping properly when you are asymptomatic, you don't have to wear a mask.This view stems from the research of Wells in 1934. The test found that due to normal air conditions, the diameter of human activity (such as speaking) was less than 100mu; the droplet of M was dripped before the ground 2 meters away from the ground 2 meters away.It will be completely dry, and the diameter is greater than 100mu; m liquid droplets, that is, droplets, will quickly settle down under the action of gravity, and control the range of droplets in the range of closer.

However, the droplets formed after the droplets will be suspended in the air, and the risk of spreading in a closed space will increase.But in the outdoor empty ventilation, the virus will not be surrounded for a long time.This means that healthy people wear masks in their daily environments. Compared with doctors wearing in the hospital environment, the latter is more effective, or that doctors need to wear masks.

Talier's Tellier's Tellier Hospital in 2006 published a review on emerging infectious diseases on the infectious diseases on the influenza virus ingotic oscillator infection.The particles of M basically do not settle down.On March 13Articles published on the pre -printing platform MEDRXIV show that the longest crown virus can exist for 3 hours in air -gas solids.

In this case, the key to wearing a mask or not is whether the new crown virus is mainly based on droplets or is mainly infected with gas solids.Although the sixth edition of the new coronary pneumonia diagnosis and treatment guide believes that the new coronary virus may only be infected with air -solidariated infection under certain circumstances, some articles show that the importance of air -soluble infection is underestimated in respiratory systems.

In addition to the direct testing and animal tests from the organism and patients, the above -mentioned Dr. Tyllier's doctor also supplemented the mathematical modeling of gas solution in the summary in 2009, and concluded that the incidence of air -solid contagion was very high.

In addition, it is worth mentioning that although the University of Toronto published on the Liuye knife in 2007, although the type A influenza is mainly greater than 5mu; M drizzle is contagious, and the transmission distance is less than 1 meter.Unusual.However, the article also proposes that the interoperability between droplets and air -soluble gum transmission does not have a clear boundary, especially when the particle size of the particles is 5mu; mochrome below, the droplet transmission may be mixed with air transmission.

It is interesting that there are asymptomatic infections in the new crown epidemic.Patients can infect healthy people without symptoms, and the lurking period can be up to 14 days.Studies have shown that the number of droplets generated for 5 minutes between normal people is equivalent to about 3,000.This also means that the risk of spreading viruses to healthy people without cough and sneezing infections is also very high.In this case, in close contact, the mask can still provide certain protection, blocking large particles in the droplet, and if air -soluble gum is produced in a specific environment, the mask protection effect will be limited.

Mask needs to cooperate with hand hygiene

Some studies have pointed out that the combination of masks and keeping hands has significant prevention effects.

A study sponsored by the US CDC, the Hong Kong Special Administrative Region Government and the University of Hong Kong in 2009 showed that the family of wearing masks, maintaining hand hygiene and diseases of hand sanitation showed that 259 households were divided into control groups, hand -wash groups, masks and hand -wash groupsEssenceThe results showed that within 36 hours of the patient's symptoms, the whole family maintaining hand hygiene and a surgical mask will reduce the family infection rate by about 70%.

Another article from the University of Michigan is different from the above experiments. The experimental object does not have obvious infected people with close contact with those. Instead, in the influenza season from 2007 to 2008, 1178 from 37 dormitories from 5 universities 1178Young people conducted a 6 -week cluster random intervention research.They are divided into control groups, masks and masks and hand cleaning groups.

The results showed that compared with the control group, the incidence of influenza -like diseases in the last week was reduced by 75%, and the incidence of only wearing a mask group was not significantly reduced.

However, the above two documents do not draw the effect of using the mask alone. The latter even said that using masks can not bring benefits, which indicates that a single personal protection measures cannot prevent the occurrence of influenza -like diseases or flu.This echoes WHO's suggestions to a certain extent. The mask is effective only with the use of alcoholic scrubbing or soapy water to wash hands.

Multiple studies remind that another key to whether mask protection is effective is whether to wear a mask correctly.Specific reminders include masks in space where there may be viruses.Do not squeeze the mask with your hands. Squeeze the virus of the surface of the mask to wet the mask with the droplets and infect the wearer.In addition, try to make the mask with the face well.Wash your hands again before wearing and picking a mask.

A single mask cannot be used for a long time.The National Professional Safety and Health Research Institute of the National Personal Protection Technology Laboratory APPAVOO Rengasamy published on the review of air -soluble in the US infection control (AJIC).It will spread to the outside world again, and there may be bacteria breeding in the humid mask, so it cannot be used for a long time.

However, it is still difficult to determine whether the mask can effectively reduce the spread of the virus in the crowd.In 2010, the mask of preventing influenza virus spread online by Cambridge University Press: The systematic summary mentioned that the effective research on the effectiveness of the mask to reduce influenza virus infection is still insufficient, and there are multiple limitations in the existing research evidence.

At present, the new crown virus still has a lot of puzzles to be solved, and the protective effect of masks also requires more research evidence.

The measures to keep their hands -on -minded atmosphere are emphasized widespread.The importance of washing hands is to reduce the risk of virus attached to the surface of other objects.On March 13th, the head of the research department of the Virus Laboratory of the National Institute of Allergies and Infectious Diseases, Neiljie Middot; Fan Middot; Dore Marlen, led the new type of coronary virus on the pre -printed platform MedrxivResearch reports in the survival stability of different objects on the surface of different objects, which mentioned that the new crown virus survives for up to 3 hours in air -gas solids, survives for up to 4 hours on the surface of the copper, and can survive on paper materials for 24 hours.The surface of plastic and stainless steel can survive for 2 to 3 days, but at this time, the toxicity of the virus has been greatly attenuated.This suggests that there is a possibility of contacting the virus in daily life, and you must wash your hands frequently.

The US CDC emphasizes that for the general public, use soap and water to use soaps and water, or to wash hands with at least 60%of alcohol.If the epidemic spreads in the community, pay attention to keeping a distance from others 2 meters (6 feet).The CDC also suggested that the official website should not be crowded, and its official website said that within 8 weeks, the organizer should cancel or delay activities of more than 50 people.

More people still choose mask protection

Although the argument of whether the healthy public is necessary to wear masks has not reached an agreement, as the epidemic has accelerated the global spread, more and more people choose to wear masks.

Earlier, European and American countries have called on the public to not buy medical masks without necessary to prevent the shortage of protection resources for medical staff.According to the New York Times, Dr. Michaelj.ryan, the executive director of the World Health Organization Health Emergency Program, said at the briefing on February 29: The world's protective equipment is facing serious pressure.What we are most concerned about is to ensure that the first -tier health workers are protected and they have the equipment they need to complete the work.

Dr. Ruian said that the mask is mainly to prevent patients from transmitting diseases to others, but the protection of healthy people is limited.The most important thing for everyone to do is wash their hands, keep their hands away from the face, and pay attention to very precise hygiene.

But the sales volume of masks still increased significantly.On March 11, a survey by the US Public Interest Research Collective (U.S.PIRG) showed that the prices of most surgical masks and disinfectants on Amazon soared at least 50%.

Researchers have compared the average price of these products over three months since the World Health Organization announced on January 30 that Amazon's high prices have been compared since the global hygiene emergency.As the epidemic spread, the price of most disinfectant and masks increased at least 50%over the average price of 90 days.Even the price of one -sixths of products directly sold by Amazon (instead of using a third -party supplier using the online market) in February was at least 50%.

On March 16, a Chinese who lived in Italy for a long time told Caixin reporter that more people already wore masks.However, there are still some traveled middle -aged and elderly people who are not worn.

As the epidemic intensifies, the mask resources have become short of shortage in some countries.The person in charge of the infectious disease department of the Italian National Institute of Health has publicly stated that the shortage of masks in Italy has become a crisis.

At present, the overseas epidemic has continued to explode, and the cumulative confirmed cases and death cases have surpassed China. The Chinese epidemic situation has continued to increase risks from overseas.On March 15th, nearly 13,000 newly confirmed cases were added outside China, showing a rapid increase.In terms of specific figures, there were 8,7464 cumulative diagnosis cases outside China, 3289 deaths, and in 149 countries and regions.Among them, there are 13 countries with a total diagnosis of more than a thousand cases, of which Italy exceeded 20,000 cases, reaching 24,747 cases; Iranian over 1,3938 cases; Korean new cases were contained, and for the first time to be less than 100 cases.Living third.