News

CDC Discourages Use of Face Masks With Vents and Valves

N95 masks with valves

 

Xinzheng / Getty Images

Key Takeaways

  • The CDC recommends people avoid masks with valves or vents since they do not adequately prevent the spread of COVID-19.
  • Neck gaiters or fleeces may actually increase the chances of viral transmission.
  • When worn properly and made of the right materials, masks reduce the spread of respiratory droplets by 80%.

The Centers for Disease Control and Prevention (CDC) is discouraging people from wearing masks with valves or vents in order to stop the spread of SARS-CoV-2, the virus that causes COVID-19. This style mask, designed for construction workers as a barrier from dust, has risen in popularity throughout the pandemic.

In guidelines updated on August 6, the CDC warns that masks with valves or vents allow exhaled air to flow freely through the openings, letting respiratory droplets slip through the surface. While these masks may protect you from any particles in the air, they don’t protect others from your potentially infectious respiratory droplets.

Sukaina Hasnie, MD, an otolaryngology resident at the University of Oklahoma College of Medicine, says preventing the spread of your own droplets is one of the most important things you can do, regardless of whether or not you feel sick.

"You do not have to be symptomatic to be able to transmit SARS-CoV-2 droplets, as studies have shown that pre-symptomatic and asymptomatic individuals carry just as much risk of transferring the virus,” she tells Verywell. "Wearing a mask at least prevents the distance and speed at which respiratory droplets can travel, reducing the risk of transmission to those around us."

Why Are Respiratory Droplets Contagious?

According to Hasnie, SARS-CoV-2 lives within the nasopharynx, which is a part of the upper airway. When we breathe, speak, sneeze, or cough, air circulates through the nasopharynx, picking up infected saliva or mucus on its way out of the body and bringing it out into the environment.

New Research Highlights Which Masks Are Most Effective

A recent study published in Science Advances helps explain why the CDC is now changing their guidance regarding masks with valves and vents. By creating a device that visually depicts the particles emitted when someone is speaking, researchers from Duke University found that wearing a proper mask eliminated the spread of droplets by 80%. But valved N95 masks fared much worse than the traditional fitted, valve-free N95 masks when it came to obstructing the spread of droplets. 

Researchers also discovered that wearing a neck gaiter—a tightly-woven, thin fleece mask that encircles the neck and face—may actually be worse than not wearing a mask at all. Since this type of mask breaks up larger respiratory particles into a stream of smaller ones, it may increase the ability of particles to linger in the air longer.

After valve-free N95s, which should be reserved for healthcare professionals, surgical masks proved the most adequate at preventing droplet transmission. The researchers also found that cotton masks become more effective when more layers are added.

If you only have a valve mask, Hasnie advises covering it up with cloth in order to protect those around you.

What This Means For You

The right mask can help prevent the spread of COVID-19. If you’re unable to obtain a surgical mask, which is especially good at blocking respiratory droplets, a multi-layer cotton mask is your best bet. Any mask with a vent or a valve should be replaced or covered with cloth.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. About Masks. Updated August 6, 2020.

  2. Moghadas SM, Fitzpatrick MC, Sah P, et al. The implications of silent transmission for the control of COVID-19 outbreaks. Proc Natl Acad Sci U S A. 2020;117(30):17513-17515. doi:10.1073/pnas.2008373117

  3. Fischer EP, Fischer MC, Grass D, Henrion I, Warren W, Westman E. Low-cost measurement of facemask efficacy for filtering expelled droplets during speech. Science Advances. Published online August 7, 2020. EABD3083. doi:10.1126/sciadv.abd3083