Updated on September 4, 2024.
In the early years of the COVID-19 pandemic, masks were a must-have to help prevent the spread of the virus, particularly before COVID vaccines were released. Gradually, as vaccines were developed and the worst of the pandemic subsided, people began wearing masks less often or more selectively.
For many people, however, masks remain an ordinary part of life. Not only can masks help reduce the spread of COVID while it persists and occasionally surges, but they can also help protect against other common respiratory viruses, such as cold and flu.
If you’re ill, wearing a mask can be a valuable way to protect your family, friends, colleagues, and those in your community from catching your illness. And if you are healthy but looking to avoid getting sick, wearing a mask can provide protection from others who have viral infections.
Why are masks effective?
If you’re sick, the best way to protect others is to isolate yourself. But it may not always be possible to stay in seclusion. If you live in a crowded household, work in a busy office, or need to be out among other people, the next best way to avoid spreading or catching a respiratory virus is to wear a mask.
Masks are essentially air filters you wear on your face. If you’re ill, they’ll filter your breath to help reduce the potentially contagious droplets and particles you exhale. If someone near you is ill, masks can help filter the air around you, reducing the germs you breathe in. Any face covering can provide at least a little protection, but those that fit loosely may let particles and droplets through the gaps. The most effective masks for illness prevention are those that fit tightly to the face and that cover the mouth and nose completely.
How are respiratory infections spread?
There are three routes that SARS-CoV-2, the virus that causes COVID-19, can enter the body: Contact, droplet, and airborne transmission.
Droplet transmission occurs when contaminated droplets escape the body of a sick person when they cough or sneeze, then land in a nearby person’s mouth or nose. These tiny droplets can travel about six feet from the person before gravity causes them to fall and settle.
Contact transmission takes place when a person touches a surface contaminated by droplets and then touches their mouth, nose, or eyes.
Airborne transmission occurs when tiny, contaminated particles escape the body and waft and linger in the air. These particles can typically travel greater distances than droplets.
Many other viral illnesses—including the common cold, respiratory syncytial virus (RSV), and measles—also spread through contact, droplet, and airborne transmission. Influenza (the flu) spreads primarily through droplet and contact transmission.
Masks aren’t foolproof. Wearing one doesn't guarantee you protection against COVID-19 or other respiratory infections. But masks are very effective at reducing the emission of contaminated respiratory droplets from infected people when they cough, sneeze, talk, sing, or breathe.
What are the best masks?
There are many types of masks that offer different levels of protection from viruses depending on their design, materials, and fit.
Cloth and disposable masks
Cloth masks and disposable masks (such as paper masks) tend to offer the lowest levels of protection to the wearer. They can block some droplets but may not protect you or others against small, airborne particles. Since there are no regulations that cover all disposable or cloth masks, it’s hard to know how much protection any type or model will offer.
Filtering respirators
For fuller protection, you need a well-fitted mask that doesn’t have gaps that can unfiltered air in or out. These include filtering facepiece respirators (FFRs) that are approved by the National Institute for Occupational Safety and Health (NIOSH). These masks are better known as N95 masks. International FFRs like KN95 masks fall into this category, though they aren’t NIOSH-approved.
Early in the pandemic, these masks were in short supply and reserved for frontline healthcare workers. As the COVID crisis evolved, they became more widely available and are now easily found at most drugstores or hardware stores.
“These higher-quality face masks used in healthcare settings provide a face seal that allows only filtered air to reach the person,” says Werner Bischoff, MD, PhD, professor of infectious diseases at the Wake Forest University School of Medicine in Winston-Salem, North Carolina. “This provides a high degree of protection against airborne pathogens.”
Elastomeric respirators
For the greatest possible protection, choose a NIOSH-approved elastomeric half-mask respirator (EHMR) or an elastomeric quarter-mask respirator (EQMR). These reusable respirators come with filters, cartridges, or canisters and filter at least 95 percent of particles out of the air.
If your priority is to protect yourself, use a respirator like an FFR, EHMR, or EQMR either with or without exhalation valves. If you believe you may be ill and your priority is to protect those around you, choose a respirator without exhalation valves, as these valves may allow viral particles to escape into the air around you.
How to use a mask the correct way
When it comes to masks, the most important goal is to make sure it’s tight-fitting and forms a seal around your nose and mouth. Be sure to secure it to keep it from slipping down.
Surgical-style paper masks can gradually become soggy, absorbing water from the humid air and a person’s breath, rendering them ineffective. Meanwhile, masks that come into contact with contaminated droplets could still spread an infection if someone touches the mask and transfers the virus to their fingers. In this way, using a mask improperly could actually increase the risk for infection. People who wear masks, for example, may tend to touch their face more often with contaminated hands.
To get the most benefit from your mask, take the following steps:
- First, wash or sanitize your hands.
- Put the mask on, with the absorbent side facing your skin. (For disposable masks, this side is usually white, with the side with color facing out.)
- Minimize gaps between the mask’s edges and your skin. Mold the stiff edge so it follows the contours of your nose.
- While you’re wearing the mask, try not to touch it. If you do, wash your hands afterward.
- Replace masks after they’ve become damp. If they’re intended for single use, discard them.
- To take off the mask, remove it from behind. Don’t touch the front, which may contain virus if you’ve been in an area where other people are exhaling viral droplets or particles. Throw the used mask into an enclosed trash can. Avoid touching your eyes, nose, and mouth when taking it off.
- Finally, wash your hands immediately after removing the mask.
If you’re using a cloth mask, make sure it's clean and wash your hands well with soap and water before putting it on and after taking it off. Wash cloth masks in hot water after each use.
Who should wear masks?
It’s a good idea to wear a mask if there’s a respiratory bug going around in your home, workplace, or community, or if you spend time in confined public indoor spaces, such as buses, trains, airplanes, stores, or restaurants. Wearing a mask can help keep you from getting sick.
If you’ve been exposed (knowingly or unknowingly) to a respiratory virus or if you have symptoms, wearing a mask can protect the people around you, too. If you’re recovering from a respiratory disease and wish to avoid spreading virus to others nearby you, many experts recommend wearing a mask in the five days after your symptoms end.
Masking is particularly important if you or anyone around you is at risk of severe illness from COVID or another respiratory infection. People at higher risk include:
- People over age 65
- Young children under age five, and especially those under six months old
- People with weakened immune systems
- People with certain disabilities, including intellectual, neurologic, and neurodevelopmental disabilities and disorders
- Pregnant people
Other precautions are still important
Masks can offer some protection from COVID-19 and other respiratory illnesses, but they don’t eliminate the need for other prevention measures. If you are trying to avoid spreading or catching a respiratory bug, follow these hygiene habits:
- Wash your hands well and often with soap and water for at least 20 seconds. If soap and water aren’t available, use an alcohol-based hand sanitizer that contains at least 60 percent alcohol.
- Avoid touching your face with unwashed hands.
- As much as possible, stay home from work or school if you are sick or have symptoms.
- Cover coughs and sneezes with tissues that you then put in the trash.
- Frequently disinfect high-touch surfaces with cleaning spray or wipes.
- When indoors, consider increasing circulation of outdoor air by opening windows and doors and turning on fans to keep the air moving.
- Avoid buildings with poor ventilation.
Staying up-to-date on your vaccinations—whether for COVID-19, the flu, or RSV, depending on your age and health profile—is also crucial for helping to prevent the spread of respiratory infections and to lower your own risk of getting sick.
