Can Medical Face Masks Prevent Viral Infections?

Due to the recent coronavirus (COVID-19) outbreak, many questions have arisen regarding the use of masks in preventing the spread of viral infections. When may a mask be effective for this purpose? What types of masks can be used?

You may be surprised that the CDC does not recommend routine use of any type of respirator or medical face mask by the general public outside of the healthcare setting to prevent the spread of any viruses—even those which may be airborne. Instead, as of April 3, the CDC recommends Americans wear cloth face coverings in public settings where social distancing is difficult.

Medical masks, on the other hand, may be beneficial in some cases, particularly when worn by an infected individual or trained medical professional.

medical masks
Only trained medical professionals should wear these masks. The exception is surgical masks, which can be worn only if an individual is ill. Verywell / Tim Liedtke

Surgical Face Masks

Surgical face masks are loose-fitting disposable masks that are readily available to the general public and can be purchased over-the-counter. They are often worn in operating rooms, dentists' offices, or during minor surgical procedures performed in doctors' offices. They are most effective at blocking infected liquids (usually bodily fluids). They do not block small particles such as airborne viruses. They also fail to provide complete protection because of the loose fit which allows air to leak around the sides of the mask.

You may encounter this type of mask in waiting rooms at doctors' offices, hospitals, or nursing homes. They are provided for use by individuals who are infected or suspect they may currently have some sort of infection. They are at least partially effective at blocking infected saliva or other large particles that may be emitted when a sick person coughs or sneezes. They can be uncomfortable to wear for any extended length of time.

Surgical face masks must be removed and disposed of properly to avoid inadvertently infecting yourself with any germs that may be on the mask. Remove it using the ties that go behind the head (or ear loops) and wash your hands immediately after removal. Surgical masks should not be worn more than once.

Surgical face masks are effective for:

  • Medical professionals participating in a procedure where the spread of body fluids may occur
  • Individuals who are sick to help to contain infected droplets emitted by coughing, sneezing, or talking

Surgical face masks are not effective for the following uses:

  • Blocking small particles like airborne viruses or COVID-19
  • Preventing the risk of contracting a virus like the flu or COVID-19 in non-infected individuals

N95 Respirators

N95 respirators are masks that are much more effective than surgical masks at filtering out small particles. In theory, they can eliminate up to 95% of small particles, including viruses. However, there are many factors that can limit their effectiveness.

These respirators are available to the general public and are often sold over-the-counter at home improvement stores. However, these masks are not necessarily intended for use in a healthcare setting, but rather to protect individuals from breathing in substances like sawdust while doing home repairs.

N95 respirators must fit properly. They are designed to fit very close to the skin so that air leakage around the mask does not occur. When used in hospitals, employees must be professionally fit tested to determine the correct size respirator for their face. Facial hair—beards in particular—can prevent N95 respirators from sealing to the face and working correctly.

Like surgical face masks, N95 respirators can protect against large particles and liquid splashes. However, they are designed for use when more protection than this is needed. They can be used in hospital settings to protect a caregiver from a patient who may have an infection that is airborne, such as tuberculosis. However, the respirator itself is only one part of several precautions taken to protect medical professionals from these pathogens. It is not intended to be used alone.

N95 respirators are uncomfortable and hot to wear for any significant amount of time. Some N95 respirators have an exhalation valve which makes it easier to breathe while wearing the mask. Special surgical N95 respirators exist for medical personnel who are involved in surgical procedures that may involve high-velocity splashing and potential aerosolization of body fluids.

Like all medical masks, N95 respirators must be put on correctly, worn correctly, and removed correctly in order to be effective. Medical personnel should be properly trained to avoid inadvertently infecting themselves while removing the respirator.

N95 respirators are not particularly effective in the hands of the general public who have not been properly measured or trained to use these devices.

Elastomeric Respirators

Elastomeric respirators are not commonly used. They are very similar to N95 respirators in their capabilities to protect against viruses, but they are not disposable. This type of respirator is made of rubber or other synthetic materials and is meant to be disinfected with bleach after each use. This makes them less than ideal for use in hospitals.

Like N95 respirators, elastomeric respirators have to be properly fitted to the face in order to be effective. This mask also has a filter that is thrown away and replaced. They can be purchased online and are often expensive.

Powered Air Purifying Respirators (PAPRs)

Many healthcare settings are moving to the use of PAPRs due to their significant advantages over N95 masks. This type of respirator resembles a loose-fitting hood or a helmet. It is connected to a battery-powered motor that pushes air through a particle filter. The filtering capabilities are higher than that of an elastomeric respirator or an N95 and they are more comfortable to wear for longer periods of time.

PAPRs must be properly cared for and maintained in order to function properly. The batteries must be fully-charged. Like other masks, they must be removed properly to avoid inadvertently infecting oneself. They also must be disinfected properly between uses. PAPRs are not a good option outside of the healthcare setting because they are expensive and require training for proper use.

A Word From Verywell

Outside of the healthcare setting, masks are generally only effective when worn by the individual who is sick. The best way for the rest of us to protect ourselves, even during an outbreak such as COVID-19, is to engage in routine hygiene practices such as proper handwashing, general cleanliness, and staying away from others who are sick.

If you suspect that you are sick you should not attend work or school. You can consider wearing a surgical mask if you have to leave the house to see a doctor.

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Article Sources
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  1. Centers for Disease Control and Prevention. Recommendation Regarding the Use of Cloth Face Coverings, Especially in Areas of Significant Community-Based Transmission. April 3, 2020.

  2. Centers for Disease Control and Prevention. Frequently asked questions about personal protective equipment. Coronavirus 2019 (COVID-19). Updated February 29, 2020.

  3. U.S. Food and Drug Administration. N95 respirators and surgical masks. Updated March 3, 2020.

  4. Radonovich L. Elastomeric and powered air purifying respirators in U.S. healthcare. Centers for Disease Control and Prevention. 2017.