The masking debate has returned, as leadership in some states like New York and California move to remove their statewide mask mandates, and others like New Jersey decide it’s time for mask mandates to end in schools. (Of course, most states did not implement them for the omicron surge to begin with.) One thing that is different about the debate this time around is the emergence of a new idea that seems, at first, to let everyone have their way: one-way masking.
“One-way masking” basically means you can wear a mask even if everyone else isn’t. The thinking goes that good, high-quality masks like KN95s and N95s filter so well against other people’s germs that there is no need for everyone to wear a mask again. For those who are immunocompromised, disabled, or otherwise high-risk, the high-quality mask is protective enough (along with vaccines) to keep the threat of infection at bay in high-risk environments, even where others are bare-faced. It’s an idea promoted by experts, like Joseph Allen at Harvard and Leana Wen of George Washington University. One-way masking was featured prominently on Monday in a New York Times piece titled “Protecting the Vulnerable.” The strategy sounds like a way to keep everyone happy and healthy, free to make their own personal choice about whether to mask up. Unfortunately, the idea of one-way masking is better in theory than in practice.
To filter as well as they can, N95s must be fit tested, as they are at hospitals or workplaces where employees are exposed to hazardous dust. Fit testing usually looks like people trying a variety of masks to see which one is best suited to the shape and size of their face. Then, the mask wearer undergoes a number of tests to see how good the seal is; these tests are outlined in detail by the Occupational Safety and Health Administration.* A study conducted earlier this year had seven people try on a number of masks and found that most N95s tested did not fit the participants sufficiently well (i.e., there wasn’t a complete seal between the mask and the wearer’s face). What’s more, the participants’ perception of whether the mask fit well often did not match up with what the actual fit was when tested by a machine. It is true that even without fit testing, these masks will still provide a good amount of protection. But if you’re surrounded by maskless individuals, and you’re at high risk for the virus, you would probably want as much protection as possible. An N95 that isn’t fit tested just isn’t going to give you that.
If you’re a civilian who has worn an N95 yourself, you can attest to the fact that they do not stay on perfectly. I recently was reminded of this fact when I wore one on a cross-country flight. I wasn’t worried, since there was a mask mandate and everyone on board was wearing a mask. Even if the masks slips and I am exposed for a moment, other people are wearing a mask as well and this reduces their chance of spreading infection to others (remember “my mask protects you”?). This is what a study published in the Proceedings of the National Academy of Sciences found as well. It looked at infection risk in a situation where a person who has the virus is speaking to someone who isn’t infected. When the person who wasn’t infected wore a well-fitting mask (an FFP2—a European counterpart to the N95), the risk of infection was 20 percent after an hour of talking. If both parties wear surgical masks, the risk of infection increases a bit, to just under 30 percent. But when both are wearing well-fitting masks, it drops to 0.4 percent. Clearly, universal masking with quality masks is better than one-way masking, and universal masking is what the study’s authors recommend.
That said, yes, it’s possible that universal masking just isn’t happening in your community. We know that politicians are unwilling to implement mask mandates for a long period of time. Despite repeat polling showing that the majority of people are supportive of mask mandates, there are still a significant amount of maskless people shopping and gathering in crowds. Because of this reality, one-way masking can be seen as a harm reduction step people can use. Strapping on your own N95 is certainly going to help, even if you are surrounded by maskless people (or people wearing cloth masks, or people wearing a mix of cloth masks and N95s). One-way masking exists on a continuum of risk mitigation, with universal masking—using masks that filter well—being the best case.
What’s frustrating, though, is that one-way masking is being proposed as a sufficient alternative to universal masking for the immunocompromised. This adds a scientific veneer of legitimacy to lifting mask mandates at a time when U.S. COVID numbers are still far too high and more than 2,000 people are dying daily. Once you’ve introduced the idea of one-way masking as an alternative, bringing back universal mask mandates becomes hard to justify. Why ask everyone to wear a mask when in theory those who are most at risk can still protect themselves?
I get it—wearing a mask can suck. I don’t exactly enjoy it, and like most people, I’d rather be living life like it is 2019. That’s the final problem with one-way masking: If we can all relate to masking being uncomfortable, why would we suggest that the immunocompromised and disabled be relegated to wearing a mask in perpetuity? Instead, we should all mask when transmission levels are high. We can scale back when they are lower, as I suggested last year in Slate: A traffic light system, denoting red, yellow, and green levels of caution, could help guide mandates and choices. If we share the burden of masking in public spaces, not only will vulnerable people be better protected, but cases will go down faster.
If you hate masking, remember that it isn’t an all-or-nothing practice. When transmission is very low, it might be reasonable to say, “I’ll mask while shopping and in indoor public places, but I’d also like to have a meal indoors.” But instead of having us each help reduce spread and make trade-offs, one-way masking places the burden entirely on the most vulnerable among us.
Correction, Feb. 15, 2022: This piece originally misidentified the Occupational Safety and Health Administration as the Occupational Hazard and Safety Administration.