Note: This article was written during the pandemic. Learn about our current face mask and visitor guidelines.

Face masks are essential to effectively preventing the spread of COVID-19. Along with frequently washing your hands and practicing social distancing, wearing a mask reduces your chance of getting infected and prevents the virus from spreading to others. It's important to wear a mask whether you're experiencing COVID-19 symptoms or not, because asymptomatic carriers can still spread the virus.

“Some people may say, ‘I was tested and I don’t have COVID-19, so I don’t need to wear a mask.’ Actually, you do, because you’re still potentially on the receiving end of the virus,” said Mary Beth Graham, MD, infectious disease specialist.

However, not all types of face masks and materials are created equal. Some face coverings are ineffective and could put you at risk of getting infected with COVID-19.

Most Effective Face Masks for COVID-19

N95 respirators 

The CDC has identified N95 respirators, also called N95 masks, as the most effective face masks against COVID-19. As such, the CDC recommends these be prioritized for use by health care workers. These are different than medical-grade masks because they offer a higher degree of filtration. N95 masks and KN95 masks (another type of respirator) are designed to filter at least 95% of airborne particles, including large and small particles.

These respirators are labeled to tell you what standards they meet, but beware of counterfeits. Respirators approved by the National Institute for Occupational Safety and Health (NIOSH) are evaluated against a specific U.S. standard that includes a quality requirement. Some respirators are designed and tested to meet international standards, which do not often have quality requirements. Counterfeit respirators are falsely marketed and sold as being NIOSH-approved and may not be capable of providing appropriate respiratory protection to workers. The Centers for Disease Control and Prevention (CDC) provides information on how to spot a counterfeit respirator.

Disposable medical-grade masks

Medical-grade masks are also known as surgical masks. You might recognize them as the blue disposable masks, but they come in different colors. You likely saw these face masks in health care settings even before the pandemic. Now, they're available in practically any pharmacy or retail store.

These masks are regulated by the FDA under 21 CFR 878.4040 and are Class II medical devices. Unlike cloth masks, when medical-grade masks are correctly fitted, studies show that they are not only more effective at preventing respiratory droplets from spreading, but they also offer some protection to the wearer. According to the FDA, these masks help block large-particle droplets, splashes, sprays or splatter that may contain virus or bacteria particles. Medical-grade masks are designed with three layers of protection, which is why they are often labeled on the box as 3-ply face masks. Medical-grade masks have varying degrees of protection, based on their thickness, which equates to the amount of non-woven polypropylene the mask is made of.

The Froedtert & MCW visitor policy requires the use of medical-grade masks at all times, in all of our facilities. If you do not have one, one will be provided to you. Medical-grade masks are designed for one-time use. Wear them once, and then throw them away.

Cloth/fabric masks

The CDC and the World Health Organization (WHO) both agree that reusable, fabric masks are effective against COVID-19. These masks should be made with a washable, tightly woven fabric and have two or more layers of material or two layers of material with a filter in between.

The CDC recommends that you choose cloth masks that:

  • Have two or more layers of washable, breathable fabric
  • Completely cover your nose and mouth
  • Fit snugly against the sides of your face and don’t have gaps
  • Have a nose wire to prevent air from leaking out of the top of the mask

Ideally, fabric masks should be washed daily. This is especially important in colder months, when our noses run more frequently and contaminate the inside of the mask. Dr. Graham recommends having multiple masks, so you have options to choose from when other masks are being washed.

While fabric masks can prevent the spread of COVID-19, they lose their effectiveness if they aren’t handled properly. This is the right way to wear, store and wash your face mask.

Least Effective Face Masks for COVID-19

The more we learn about COVID-19, the more we understand why certain types of face masks are better than others. The face coverings that you should avoid wearing include:


They leave a large opening underneath your chin, which could allow particles infected with COVID-19 to get into your nose and/or mouth.

Face shields by themselves

When worn with a face mask, face shields provide an extra defense against COVID-19. If you wear one without a mask, viral particles are able to travel out and around the face shield, potentially infecting you or others.


Many scarves aren't thick enough to keep particles infected with COVID-19 from entering your nose or mouth. If you're going to wear a scarf outside, make sure you wear a face mask underneath it.

There is not yet conclusive data on whether gaiters are effective face masks for COVID-19. A Duke University study suggested that wearing gaiters could be worse than not wearing any covering, while a study from the University of Georgia found that multilayer gaiters were more effective than some types of face masks. Dr. Graham said the important factor for gaiters is the number of layers: “If you get a gaiter made of cotton that’s triple-layered, then it would be fine.”

For those who have had trouble breathing when wearing a mask, Dr. Graham recommends trying a different style of face covering, for example, switching from a cloth mask to a disposable one. Considering the recent surges in positive COVID-19 cases and the number of statewide mask mandates across the country, wearing a face mask — and wearing it properly — is in everyone’s best interest.

“The recommendation to wear a mask when you are in public and unable to social distance is not going away. Masks are intended to protect everybody, so trying to find a way to comply and wear some sort of mask is a good thing,” she said. “It’s the right thing to do.”

More information on the choosing and wearing most effective types of face masks is available from the CDC and the WHO

brad weirich

Your article just said "Most Effective Face Masks for COVID-19
Disposable medical masks and Clothe face masks", (and NOT N95 or even mentioned KN95.) ?

Froedtert & MCW

Hello Brad – The CDC has identified that the N95 mask is the most effective and, as such, also recommends that these masks be prioritized for use by health care workers. The CDC also recommends that the public wear disposable medical masks or cloth face masks with multiple layers, which are effective. Recently, public health professionals have recommended that the public consider wearing multiple masks to assure adequate covering of your mouth and nose.


Thank you for the very informative article!! I listen to you often on TMJ 620 radio.