The CDC provides recommendations for wearing face masks and Johns Hopkins Medicine provides guidelines for our patients.

Lisa Maragakis, M.D., M.P.H., an expert in infection prevention, answers questions about face masks.

Can wearing a face mask prevent coronavirus from spreading?

Yes. Since the coronavirus can spread through droplets and particles released into the air by speaking, singing, coughing or sneezing, masks are very helpful to prevent the virus from spreading in crowded indoor public places, especially those that contain a mixture of vaccinated and unvaccinated individuals.

What is the best face mask for COVID-19?

The CDC provides an overview of various types of masks and respirators. In general, the most important things you can do are to choose a mask that fits well, and wear it consistently and properly when it is recommended or in situations that you are required to do so.

Anytime you wear a mask, make sure:

• You clean your hands with soap or hand sanitizer before putting the mask on or taking it off.
• It is worn consistently and appropriately. A mask that is frequently pulled down to breathe or talk, or is worn under the nose, is not effective.
• The mask conforms to your face without gaps — it is important that most of the air you breathe in and out flows through the mask rather than around the mask through gaps at the sides, top or bottom.
• Your cloth mask is made from several layers of tightly woven fabric and fits well over your nose and mouth to be an effective filter.
• The mask has a flexible nose bridge to conform to the face and prevent fogging of eyeglasses.
• It stays in place while talking and moving, so it can be worn without slipping and so it does not require you to touch it frequently.
• The mask is comfortable enough to wear without adjusting it for the time you need to keep it on.

Here are brief descriptions of mask types:

Cloth Masks

In non-health care settings, multiple-layer fabric cloth masks are excellent barriers for containing respiratory droplets and interrupting viral transmission if they are worn consistently and properly, covering the nose and mouth.

Procedural and Surgical Masks

These are loose-fitting masks designed to cover the mouth and nose. Medical grade surgical or procedural masks provide excellent protection due to their filtration and fluid resistance. A simple “knot and tuck” technique can be used to improve the fit of rectangular surgical or procedural masks. This video from the CDC demonstrates this technique.

N95s and Other Respirators

N95 respirators offer a higher level of filtration than cloth, surgical or procedural masks. However, they are not necessary to protect people from the virus under normal circumstances. In order to be optimally effective, respirators must be fit-tested and worn properly, tightly fitted against the person’s face.

N95 respirators, Dräger respirators and powered air purifying respirators (PAPRs) are used by medical professionals caring for patients with COVID-19, and when performing high-risk or aerosol-generating procedures.

N95s and KN95s are available to the public and, if worn consistently and properly, are effective to help prevent the spread of COVID-19.

Face Shields

A face shield is a piece of rigid, transparent plastic attached to a headband. The plastic piece covers the face, extending below the chin.

You might have seen face shields on some health care providers, even before the COVID-19 pandemic. Dentists and dental hygienists sometimes wear them when working close to patients’ mouths. Doctors, nurses and technologists might use face shields, together with face masks, when performing procedures that could propel blood or other substances into the air.

At Johns Hopkins, care teams wear eye protection or face shields over masks or N95 respirators for additional protection. We do not recommend wearing a face shield in place of a mask or wearing clear shield-like face masks, which are different than face shields but have gaps around the face and therefore do not provide the same protection as wearing a mask.

In general, you do not need a face shield in public settings if you are fully vaccinated or wear a mask and maintain physical distancing.

Do I need to wear a face mask if I currently have COVID-19?

Yes. If you are actively infected with the coronavirus and cannot stay completely away from others in your home, droplets from your nose or mouth could infect another person. Stay away from others as much as possible and wear your mask around others until your doctor says it’s safe to discontinue wearing it.

Do I need to wear a mask if I am fully vaccinated and have received a booster?

Although being fully vaccinated and/or boosted reduces your chance of catching or spreading the coronavirus, it does not eliminate it entirely. If you are infected with the coronavirus and do not know it, a mask keeps your respiratory droplets and particles from infecting others. Check the mask recommendations in your area to help decide whether you need to mask.

Do I need to wear a mask if I am around someone who is at greater risk for getting COVID-19?

It is important to protect other people from getting COVID-19. Even if you are fully vaccinated and have a booster, wearing a mask provides an extra layer of protection, especially when you are around a person who may be at greater risk of COVID-19. Likewise, people who are at greater risk should strongly consider wearing a mask to help protect themselves.

Why do mask regulations keep changing?

There are many factors that go into mask recommendations. These include the infection rate in the local area, new variants that may be quick to spread such as omicron, and the setting (crowded indoor areas are more likely to be places where COVID-19 may spread). The CDC, local communities and public spaces such as hospitals review these factors to determine the safest approach to reduce the spread of COVID-19. While it may be tiring to keep up with the latest recommendations and to mask frequently, it is an important way to protect yourself and others.

How effective are neck gaiters and bandanas in stopping the spread of the coronavirus? Are masks with exhalation valves OK?

None of these three types of face coverings works as well as a proper face mask. A good mask has a double layer of washable, breathable fabric that helps keep the wearer from spreading potentially infected droplets into the air. A bandanna tied around the face does not work as well as a mask because it is open at the bottom. A gaiter (a tube of thin, stretchy knit fabric that can be worn around the neck and pulled up to cover the nose and mouth) is usually too thin to provide adequate protection. Likewise, masks with exhalation valves can allow your droplets to escape into the air.

Johns Hopkins Medicine does not permit bandanas, gaiters or masks with exhalation valves to be worn by patients, staff members or visitors at our locations. We do not recommend clear shield-like face masks, which are different than face shields but still have gaps around the face and therefore do not provide the same protection as wearing a mask. 

Can I get a face mask exemption or waiver?

No, you cannot get a waiver or exemption from wearing a face mask. Fake cards and flyers claiming the bearer is exempt from mask-wearing regulations because of a physical or mental condition covered by the Americans with Disabilities Act (ADA) have circulated.

The United States Department of Justice issued a statement about these fake mask exemptions, explaining that the cards and flyers are fraudulent.

How do I wash my cloth face mask?

• Masks made of fabric, such as cotton, can be washed in your regular laundry using hot water.
• Disposable, blue surgical masks cannot be laundered or cleaned and should be thrown away when they are visibly soiled or damaged.
• After laundering your fabric masks, tumble dry them in the dryer on a high setting.
• You might consider using a nonscented laundry detergent if you are sensitive to perfumes, so it is easier to wear masks.
• You can also hand-wash your mask, using hot, soapy water. Scrub the mask for at least 20 seconds and dry it on high heat in the dryer.
• Store clean masks in a clean place when you are not using them.

How often should I clean my face mask or covering?

• You should clean your mask after every wearing. This reduces the risk of spreading the coronavirus or other germs.

How many face masks do I need?

It’s a good idea to have at least two. This way, you will have a fresh mask if one is in the wash.