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Surgical Masks, Respirators, Face Shields: Which Masks Actually Protect Against Coronavirus?

Surgical Masks, Respirators, Face Shields: Which Masks Actually Protect Against Coronavirus?
Which masks actually protect against coronavirus? (Credit: iStock)

The world is facing a shortage of masks and other protective equipment against the new coronavirus, the head of the World Health Organization warned on Friday, February 7th. Surgical masks are especially in demand. But are they really effective? What kind of masks actually protect against Covid-19? Read this article to find out.

Kolmi-Hopen is one of the major manufacturers of single-use medical products. Under normal circumstances, their facility in France makes 150 million surgical masks and over 20 million respirators per year. Today, with the rising demand, they have been requested to make over 500 million masks altogether. This is what Gérald Heuliez, managing director of Kolmi-Hopen, told French news agency AFP.

In the meantime, companies like Foxconn have said they would make 20 million masks by the end of this month to face the world demand. 

Since the outbreak, people in China and the rest of the world have rushed to their local pharmacies to get surgical masks. But there are different types of masks on the market, and not all of them are really effective against this virus. So, which masks actually offer protection?

Surgical Masks vs. Respirators

There are two different types of masks: surgical masks and respirators. 

DACH Schutzbekleidung surgical mask. (Credit: DACH Schutzbekleidung)
Surgical mask (Credit: DACH Schutzbekleidung)

Surgical Masks

A surgical mask is a disposable medical device that can be bought in pharmacy and that protects against infectious agents transmitted by “droplets.” These droplets can be droplets of saliva or secretions from the upper respiratory tract when the wearer exhales. 

If worn by the caregiver, the surgical mask protects the patient and his or her environment (air, surfaces, equipment, surgical site). If worn by a contagious patient, it prevents the patient from contaminating his or her surroundings and environment. These masks should not be worn for more than 3 to 8 hours.

A surgical mask can also protect the wearer from the risk of splashes of biological fluids. In this case, the surgical mask must have a waterproof layer. It can also be equipped with a visor to protect the eyes.

But a surgical mask does not protect against “airborne” infectious agents so it will not prevent the wearer from being potentially contaminated by a virus such as the coronavirus.

Respirators

FFP2 Respirators (Credit: Left: 3M, Right: Honeywell)

A respirator is personal protective equipment that prevents the wearer from inhaling aerosols (dust, smoke, mist) as well as vapors or gases (disinfectants, anesthetic gases) that are health hazards. Unavailable in pharmacies, it protects the wearer from airborne infectious agents i.e. against contamination by a virus such as coronavirus, SARS, H1N1, etc.

Respirators are divided into two categories: insulating and filtering. Filtering respirators consist of a facepiece and a filtering device. Sometimes the filter element is integrated into the facepiece. Depending on the type of filter, the mask will either be effective only against particles, only against certain gases and vapors, or against particles, gases and vapors.

Filtering respirators can sometimes also be equipped with an exhalation valve to improve user comfort. The valve prevents condensation inside the mask, misting on the glasses and helps the user breathe in and out easily.

It should be noted that respirators also protect those who wear them from inhaling “droplets” of infectious agents.

Respirators can be disposable or reusable. In the second case, it is possible to replace the filter when it is full.

What Are the Standards ?

Each of these two types of masks is subject to different standards and regulations depending on the country or geographical area.

Surgical masks are tested in the direction of exhalation (from inside to outside). The tests take into account the efficiency of bacterial filtration. 

In Europe, they must comply with the European standard EN 14683, which has 3 levels of bacterial filtration efficiency (BFE1, BFE2, Type R).

In the United States, they must respect ASTM standards which have three levels of protection (from low risk of exposure to fluids to high risk of exposure to fluids)

Respirators are tested in the direction of inspiration (from outside to inside). The tests take into account the efficiency of the filter and leakage to the face. 

In Europe, they must meet the European standard EN 149: 2001 which has three classes of disposable particulate respirators (FFP1, FFP2 and FFP3).

  • FFP1 refers to the least filtering of the three masks with an aerosol filtration of at least 80% and leakage to the inside of a maximum of 22%. This mask is mainly used as a dust mask (home renovations and various types of work).
  • FFP2 masks have a minimum of 94% filtration percentage and a maximum of 8% leakage to the inside. They are mainly used in construction, agriculture, and by healthcare professionals against influenza viruses. They are currently used for protection against the coronavirus.
  • FFP3 masks are the most filtering masks of the FFPs. With a minimum filtration percentage of 99% and a maximum of 2% leakage to the inside, they protect against very fine particles such as asbestos.

In the United States, respirators must meet NIOSH (National Institute for Occupational Safety and Health) standards. Within this standard, there are several classes of respirators depending on the degree of oil resistance:

  • Class N: no oil resistance. A distinction is made between N95, N99 and N100. The number after the letter indicates the percentage of filtration of suspended particles.
  • Class R: mask resistant to oil for up to eight hours. Here again, a distinction is made between R95, R99 and R100.
  • Class P: a completely oil-resistant mask. There are also P95, P99 and P100.

So, Which Masks Protect Against Coronavirus?

A contagious patient should wear a surgical mask as soon as contagion is suspected.

For caregivers: it is necessary to wear a respirator of at least class FFP2 or FFP3 for maximum filtration of particles and aerosols when caring for a patient who is infected or suspected of being so.

Face Shields

With the mask shortage, new alternatives to those masks have appeared like the face shields.

faceshield
Face shields allow for prolonged mask life. (Credit: University of Portsmouth)

A face shield provides almost complete protection by its anti-projection effect on the three areas through which the virus enters: the mouth, the nose and the eyes. Face shields are mainly used in resuscitation. It can easily be cleaned or disinfected, so it can be reused, and it allows for a certain degree of airflow without pain for the person who wears it.

Face shields are made of transparent Plexiglas screens or plastic that protect against potentially infected droplets and sputters.

READ ALSO| Our interview with Stratasys which is 3D printing face shields

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