What Is 'One-Way Masking'—And How Can It Protect You From COVID?

Even if you’re the only person masking up on public transportation, health experts say you still have some protection against COVID-19.

Woman With Mask On The Cabin Of A Plane.
Photo: Luis Velasco / Stocksy

Wearing a mask is now optional on airplanes and other modes of public transit in the U.S., in most cases. The mask mandate for public transportation—which had been in place since January 2021—was struck down by a federal judge in Florida on Monday, after being ruled as unlawful.

The news has garnered mixed reactions. Some people rejoiced, with plane passengers removing their face coverings gleefully mid-flight; others, including immunocompromised people and parents of children, still unable to be vaccinated, voiced fear and concerns about safety—especially as BA.2 continues its spread across the country.

But for those who have chosen to remain masked in these public settings, there's positive news: Health experts maintain that travelers still have the ability to protect themselves by continuing to wear a mask—even if no one else around them is.

"One-way masking can still provide significant protection to the user, as the mask itself still filters respiratory droplets, as long as the mask fits well and is worn for the duration it is needed, Christopher Sulmonte, MHA, project administrator for the Johns Hopkins Biocontainment Unit and a masking expert, told Health.

Here's what you need to know about one-way masking, and how it can still provide protection against COVID-19.

Effectiveness of One-Way Masking

One-way masking is the act of wearing a mask in an environment where the surrounding individuals are not masked. According to Sulmonte, even if you are the only one wearing a mask in these situations, it can still provide a significant amount of protection against COVID-19.

This is because masks can filter any respiratory droplets and block any particles that may have escaped from the people around you. This is especially true when wearing a mask that fits well across your face, is multi-layered, and is worn for the entire duration you may need it for.

"For example, in healthcare settings where staff interact with unmasked and highly infectious patients for long durations, we have seen how effective masking is in protecting healthcare workers from exposures and infection from a wide variety of infectious diseases, including COVID-19," Sulmonte said.

Although the most benefit for avoiding COVID-19 and other respiratory illnesses comes from all people wearing masks correctly, there is ample data that shows mask-wearing can protect the wearer, even in settings where others aren't masked up, according to David Souleles, MPH, director of the COVID-19 Response Team Program in Public Health at the University of California, Irvine.

Soules referenced a recent study from the Centers for Disease Control and Prevention (CDC), which found that people who consistently wear masks that are both comfortable and well-fitting are less likely to get COVID-19, compared to those who don't regularly wear face coverings.

Additionally, a modeling study published in December 2021 found that, while passengers on an airplane still had a high risk of catching COVID-19 from an infected passenger sitting in close proximity to them, wearing a mask could reduce the risk of infection by up to 54%, depending on seating arrangements.

Masking is effective in real life scenarios, too: Following a 2020 COVID-19 outbreak at a hotel in Switzerland, local officials advised against wearing only face shields without additional face-mask protection. Following contact with a COVID-positive person, all people who wore only face shields also contracted COVID-19, while those wearing face masks did not.

Best Masks for One-Way Protection

While many studies have proven a mask protects the person who is wearing it, the level of protection depends on the type of mask, mask material, how consistently people are wearing them, and the rate of infection in the community, Eric Cioe-Peña, MD, director of global health and emergency department physician at Staten Island University Hospital, told Health.

"Not all masks are equal. A KN95 or N95 mask protects the wearer significantly against COVID, even if the other people don't wear a mask," Dr. Cioe-Peña said. "One person wearing a KN95 is better in some studies than both people wearing a surgical mask," though he added that there is still some "one-way" protection for surgical masks, too.

According to the CDC, high-quality respirators—KN95 or N95 face coverings—provide the most protection from a respiratory infection. Though surgical masks and cloth masks still offer some amount of protection to wearers, they must be worn correctly (no gaps, or wet or dirty material), and they provide even more protection when they're layered together.

"The multiple layers of the mask filter potential virus-containing droplets, while the fit of the mask maximizes the amount of air that is filtered while the mask is worn," Sulmonte said.

The bottom line, according to Souleles: "As we have progressed through the pandemic and learned more about how COVID-19 transmits and have more data on mask effectiveness, we now know that my mask protects me from infection as well as others from being infected, should I be infectious," he said. "Your level of protection is further enhanced if you are also vaccinated and boosted."

Other Ways to Protect Yourself

There are other things that travelers can do beyond wearing a mask that can reduce the risk of transmission. This includes getting vaccinated for COVID-19 if you are eligible and staying up to date with booster shots, as well.

Additionally, Sulmonte said social distancing from people who aren't wearing masks, especially if you are an older adult or immunocompromised, can help lower the risk.

"Just like masking and vaccination, minimizing time in dense crowds (especially in low ventilated or indoor locations) can lower the risk of COVID-19 exposure," Sulmonte said.

Souleles added there are other steps you can take to protect yourself:

  • Stay home if you are experiencing symptoms.
  • Test if symptomatic.
  • Is positive, isolate using current public health recommendations.
  • If you are hosting an event, consider utilizing an outdoor venue.

"COVID-19 continues to challenge us as a community, but there are steps we can all take individually to protect ourselves and our communities," Souleles said. "We have the tools to lower the risk of COVID-19, we just need to use them when they are indicated."

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

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