Which Masks Actually Protect Against Coronavirus?

9th April 2020

Since the outbreak, people have rushed to get surgical masks.  But not all of them are really effective against the Covid-19 virus. So, which masks actually offer protection?

Surgical Masks vs. Respirators

To start with, there are two different types of masks: surgical masks and respirators.

 

>>> A surgical mask, also known simply as a disposable face mask, is intended to be worn by health professionals during surgery.  They are not designed to protect the wearer from inhaling airborne bacteria or virus particles.

If worn by the caregiver, its purpose is to protect the patient and their environment (air, surfaces, equipment).  If worn by a contagious patient, it prevents the patient from contaminating their surroundings and other people in the environment.  These masks should not be worn for more than 3 to 8 hours.

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.

>>> A respirator is personal protective equipment that prevents the wearer from inhaling aerosols (dust, smoke, mist) as well as vapours or gases that are health hazards.  This also 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.  The types of filter depend on how effective the mask is against airbourne diseases, which I will cover later.

All respirators also protect those who wear them from inhaling “droplets” of infectious agents.  Respirators can be disposable or reusable.

What are the Standards?

Both surgical masks and respirators are subject to different regulations depending on the country, the information below is based on European standards.

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

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

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 maximum 22%. This mask is mainly used as a dust mask (home renovations and various types of work).
  • FFP2masks have a minimum of 94% filtration percentage and maximum 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.
  • FFP3masks are the most filtering mask of the FFPs. With a minimum filtration percentage of 99% and maximum 2% leakage to the inside, they protect against very fine particles such as asbestos.

So, Which Masks Protect Against Coronavirus?

 A contagious patient should wear a surgical mask as soon as contagion is suspected.  For caregivers it is essential to wear a respirator of at least class FFP2 for maximum filtration of particles when caring for a patient who is infected or suspected of being so.

Should a Disposable or Reusable Mask be Used?

>>> Surgical masks are disposable medical devices that must be disposed of after use.

>>> Respirators can be disposable or reusable.  In the second case, filters must be replaced when full or they will cease to be effective.

Generally speaking, the effective life of a surgical mask or respirator can range from 3 to 8 hours.

Reusable masks have to have their filters changed often but often people forget to do so or there is a lack of filters so they aren’t changed regularly.  This means disposable masks are often more suited to the current environment, especially with regards to Covid-19.