Can Surgical Masks Prevent New Coronavirus? How to Wear Surgical Masks Correctly

Recently, everyone is very nervous and worried that they will be infected with the new coronavirus. Do I have to wear N95 masks? Can ordinary medical surgical masks prevent neocrown virus? How to wear a mask? Now we have done some homework on medical surgical masks for everyone.

 

American Medical Surgical Mask

 

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Medical masks are usually called Surgical Mask or Procedure Mask, and may also be called Dental Mask, Isolation Mask, Medical Face Mask, etc. In fact, they are the same. The name of the mask does not indicate which protection effect is better.

Although various English nouns actually refer to medical masks, they often have different styles. The traditional surgical masks used in the operating room are "Tie-On" straps (above left), so many are called surgical masks. Surgical masks are also strap-on. For ordinary people, the "Earloop" ear-hook medical mask (right above) will be more convenient to use.

 

Medical surgical mask quality standards

Medical surgical masks in the United States need to be approved by the FDA. They require certain particle filtration efficiency, fluid resistance, and flammability data to meet the standards. So what standards will medical surgical masks have? The FDA requires medical masks to provide the following test data:

Bacterial Filtration Efficiency (BFE): A measure of the ability of medical masks to prevent the passage of bacteria in droplets. The ASTM test method is a 3.0 micron-sized bio-aerosol containing Staphylococcus aureus to see how many bacteria can be removed by a medical mask. It is expressed as a percentage (%). The higher the percentage, the stronger the mask's ability to block bacteria.

Particulate Filtration Efficiency (PFE): It measures the filtering effect of medical masks on submicron particles (virus size) with pore sizes between 0.1 micrometer and 1.0 micrometer. It is also expressed as a percentage (%). The higher the percentage, This indicates that the mask's ability to block the virus is stronger. The FDA recommends using unneutralized 0.1 micron-sized latex balls for testing, but larger particles can also be used for testing, so pay attention to whether there is a "@ 0.1 micron" sign after the PFE%.

Fluid Resistance: Measures the ability of surgical masks to resist the penetration of blood and body fluids, expressed in mmHg. Higher values ​​indicate better protection. The ASTM test method uses artificial blood to be sprayed under three pressures of 80mmHg (venous pressure), 120mmHg (arterial pressure), or 160mmHg (potential high pressure that may occur during trauma or surgery) to see if the mask can block fluid from the outer layer to the Inner layer.

Differential Pressure (Delta-P): Measure the air flow resistance of medical masks, visually display the permeability and comfort of medical masks, in mm H2O / cm2, the lower the value, the more breathable the mask.

Flamemability / Flame Spread: As there are many high-energy electronic medical equipment in the operating room, there are many potential ignition sources, and the oxygen environment is sufficient, so it must have certain flame retardancy as a surgical mask.

Through BFE and PFE tests, we can understand that the use of ordinary medical masks or surgical masks as epidemic masks has a certain effect, especially to prevent some diseases mainly transmitted by droplets; but medical masks cannot filter tiny particles in the air. It has little effect on preventing airborne germs and airborne diseases.

 

ASTM Medical Surgical Mask Test Standard

ASTM Chinese is called the American Materials and Testing Association. It is one of the largest international standardization organizations in the world. It specializes in researching and formulating material specifications and test method standards. The FDA also recognizes ASTM's test methods for surgical masks. All are tested using ASTM standards.

 

The ASTM test and evaluation of surgical masks is divided into three levels:

ASTM Level 1 Lower Barrier

ASTM Level 2 Moderate Barrier

ASTM Level 3 High Barrier

 

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It can be seen from the above that the ASTM test standard uses 0.1 micron particles to test the filtration efficiency of PFE particles. The lowest Level 1 medical mask must be able to filter 95% or more of the bacteria and viruses carried in the droplets, and the more advanced Level 2 and Level 3 medical masks can filter 98% or more of the bacteria and viruses carried by the droplets. The biggest difference between the three levels is fluid resistance.

When friends buy medical masks, they should look at the certification standards written on the package, which standards are tested in accordance with which standards. For example, some masks will simply describe "Meets ASTM F2100-11 Level 3 Standards" (as shown below), which means that it conforms to the ASTM Level 3 / High Barrier standard.

 

Some products may also specify each measurement value. The main effect of virus prevention is "PFE% @ 0.1 micron (0.1 micron particle filtration efficiency)". As for the parameters that measure the resistance and flammability of the fluid that blocks blood spray, Whether it is the highest standard has little effect.

CDC Vaccination Mask Instructions

Medical Surgical Mask: It can prevent the wearer from spreading the germs, and it can also protect the wearer from sprays of droplets and liquids. It has a preventive effect on diseases transmitted by large droplets; but ordinary medical masks cannot filter. Small particle aerosols have no preventive effect on airborne diseases.

N95 mask: it can block large particles and 95% non-oily small particles aerosol. Correctly wearing NIOSH certified N95 mask can prevent airborne diseases and can be used as the lowest level protective mask for TB tuberculosis, SARS and other airborne diseases However, N95 masks cannot filter gas or provide oxygen, and are not suitable for poisonous or hypoxic environments.

Surgical N95 Mask: Meets N95 particle filtration standards, can prevent droplet transmission and airborne diseases, and can block blood and body fluid splashes that may occur during surgery. The FDA approved it as a surgical mask.

 

Can wearing a mask prevent new coronaviruses?

 

New Coronavirus Transmission Route

At present, experts believe that the new Coronavirus (2019 Novel Coronavirus) is mainly transmitted through respiratory droplets and can also be transmitted through contact.

Therefore, the transmission route of the new crown virus is actually very similar to that of the influenza virus. Without a complete understanding of the new virus, we can refer to some previous research data on whether wearing a mask can prevent the influenza virus.

Wearing a mask helps prevent viral infections

A study published in the International Journal of Infectious Diseases assessing the risk of influenza infection among family members who have children with influenza-like illness, compared with N95 masks that are worn with general medical masks and not tested for gas density (Non-fit-tested P2 masks) and three cases without masks. The results of the study showed that family members who wore masks correctly had an 80% reduction in the risk of catching the flu. However, there was no significant difference in the effect of using ordinary medical masks and untested N95 masks.

Another study in the Annals of Internal Medicine surveyed 400 people with the flu, and the results showed that when washing hands and wearing a mask frequently, patients' families were at 70% less likely to get the flu.

A report by the University of Michigan is to study the effect of non-drug interventions (NPI) on the prevention of influenza in the event of a vaccine shortage. The study surveyed more than 1,000 college students living in student dormitories and compared "no special defense measures vs. The prevention effect of wearing a mask vs. wearing a mask + washing your hands frequently was found that wearing a mask alone cannot prevent the flu, but wearing a mask and washing your hands frequently can reduce the risk of influenza by 75%.

In addition, a CDC study showed that patients wearing medical masks can greatly reduce virus aerosol emission (a 3.4-fold reduction), in which for small particles smaller than 5 microns, the number of viral copies can be reduced by 2.8 times; for particles larger than 5 microns , Can reduce the number of virus copies by 25 times.

It can be seen from the above that, for influenza virus and new coronavirus, combined with wearing a mask and washing hands frequently, can effectively reduce the possibility of virus transmission through droplets and contact, thereby reducing the risk of infection.

 

How to wear medical surgical masks?

Medical masks usually have two sides, blue and white, also called blue and white masks. In fact, medical masks have at least three layers:

The outer layer is mostly blue or other colors and is made of water blocking material, which can prevent liquid from entering the mask to the inside;

The filter layer in the middle can block germs;

The inner layer is white and can absorb moisture and absorb moisture during exhalation.

Therefore, when wearing a mask, you should face the white side to yourself and the colored side to the outside to have a protective effect.

 

Correct wearing of surgical masks:

1. Clean your hands before wearing a mask;
2. Choose a mask that fits your size, hold the metal strip on the side of the mask upwards, hang the elastic bands on the back of the ears, and then fully unfold the outer fold to ensure that the mask completely covers the mouth, nose, and chin, and then squeeze with both hands Metal strip nose clip to make the mask fit the face completely;
3. Try not to touch the mask again after wearing it. If you must touch it, you should wash your hands before and after;
4. When removing the mask, try not to touch the outer layer of the mask, you should remove the mask by pulling the elastic band behind the ear;
5. After using the mask, it should be discarded in the trash can and covered, and the hands should be washed immediately. The medical mask is disposable and should not be reused.

 

When to wear a mask:

When you are close to a sick person, you should wear a mask when you are 6 feet / 2 meters away (data show that flu patients can infect people within 6 feet around them)

If you are ill, wear a medical mask before approaching others;

If you have symptoms of an infectious disease such as flu or new pneumonia, you should consciously wear a medical mask when you see a doctor to prevent the spread of germs.

If there are many people around you who cough and sneeze, wearing a mask can also prevent yourself from being sprayed with droplets, but medical masks cannot filter small particles of aerosol suspended in the air. In other words, when walking on an open street and no one is nearby, the effect of wearing a medical mask will not be different.

 

How long can a medical mask be worn?

It is generally recommended that ASTM-certified medical surgical masks be used continuously for no more than 4 hours, as the protective effect will decrease over time. In addition, when the medical mask becomes wet, dirty, or damaged, it will also affect the protective effect, and it should be replaced with a new mask.

Medical masks should be discarded into a bin with a lid after use to reduce the chance of germs spreading.

Disposable masks should not be reused. After washing, heating, chemical substances such as alcohol, ultraviolet rays, etc., cleaning, sterilization and disinfection are likely to damage the waterproof layer and filter layer of the mask. How many protective effects can there be after disinfection? Testing is generally not recommended. However, in the case of material shortage, the method of choosing dry heating or ultraviolet disinfection masks is relatively more reliable.

Picture from Internet, copyright belongs to original author

 

In addition to wearing a mask, wash your hands frequently!

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As mentioned before, wearing a mask to prevent viral infection is not very effective, because the virus is not only transmitted by droplets, but can also be transmitted directly or indirectly through mucous membranes such as the oral cavity, nasal cavity, and eyes; in addition, people infected with the new coronavirus The incubation period can also spread the virus, and it may become infected when it comes in contact with a carrier, or when it comes in contact with an item contaminated with the virus.

If your personal hygiene is not good, you can remove the mask by touching the outside of the mask that is blocking many germs, and then rubbing your eyes and grabbing food without washing your hands. That's tantamount to introducing the germs to yourself. The protection of the mask is useless. Already.

Therefore, it is very important to develop a good habit of not touching the eyes, nose, and mouth directly with your hands, and washing your hands frequently and carefully!

 

When you can clearly see the dirt, wash your hands with soap and running water for 20 seconds, and sing the birthday song twice quickly;

You can follow the "Seven Steps of Washing Hands" to learn the correct hand washing steps:

 

When there is no obvious dirt, you can wash your hands with soap and water, or use hands-free hand soap with an alcohol concentration of not less than 60% to clean your hands.

When going out, it ’s best to carry an anhydrous hand sanitizer with you to clean your hands at any time.

 

Write at the end

In addition to personal hygiene, we should also pay attention to the hygiene of the home and work environment. Especially when someone is sick around you, you should touch the surface of some objects that are often touched by both hands, such as mobile phones, mouse keyboards, desktops, door handles, refrigerator door handles, light switches, TV remote controls, toilet flush handles, faucets, etc. Sterilize at least once a day with alcohol or disinfected wipes.

 

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