As travelers begin shedding masks in many public transportation settings, questions over safety concerns, particularly for those who cannot be vaccinated yet or those who are immunocompromised, are being raised.
Will wearing a mask protect you if no one else is wearing one?
Yes, masks still give some protection from COVID-19, but they work better if others wear them too, experts say.
"One-way masking or just masking your high-risk (populations) certainly will reduce the risk for those individuals, but it is safer for everyone if everyone's wearing a mask, and there are some places where that's still a good idea," said Dr. Emily Landon, an infectious disease expert at UChicago Medicine.
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High-quality masks work in two ways, according to Carl Bergstrom, a University of Washington evolutionary biologist who studies emerging infectious diseases. First, they protect the wearer by limiting the number of infectious particles inhaled, and they protect others by limiting particles exhaled if the wearer is infected.
The CDC continues to recommend that people mask up indoors while traveling, despite a judge's recent ruling voiding a national travel mask mandate.
The mask mandate for transportation began in February 2021, shortly after President Joe Biden took office, and was extended several times. Last week, the CDC extended it again until May 3.
The CDC said the extra time was needed to study the BA.2 omicron subvariant, which is now responsible for the vast majority of cases in the U.S.
But a ruling by a federal judge has ended — at least for now — the requirement that people wear masks on planes and public transportation. The decision by a lone judge in Florida toppled 14 months of government insistence that travelers wear masks to reduce transmission of COVID-19.
Illinois Gov. J.B. Pritzker followed that news Tuesday by saying he will amend an executive order requiring masks on public transportation to align with the judge's ruling.
Still, Pritkzer continued "to urge Illinoisans to follow CDC guidelines and, most importantly, get vaccinated to protect yourself and others.”
Landon echoed the recommendation from the CDC and Pritzker to continue masking on public transportation.
"People should still be wearing masks on public transportation. Absolutely. There is no question in my mind that it protects people and keeps them safer," she said. "Airlines are saying that airplane air is filtered and it is very clean, recirculated a lot and has some of the best ventilation and better ventilation standards than you see in many buildings. That is of course true and it will help you. If you're sitting in row 10 it will keep you from getting COVID from someone in row 30, but it doesn't help you at all from the people in rows eight, nine and 11 and 12. And so there's still a significant amount of risk because of the crowding and the close contact. And that is what makes masks really effective."
Landon said airplanes are likely safer for unmasking than other forms of public transportation.
"Airlines are probably the safest," Landon said. "Trains, buses, cars and Ubers - they are the least safe. There's not as much ventilation and you have no idea who you're smashed into that bus with."
Air filtration on planes is generally excellent, but boarding and exiting a plane can put people close together in spaces with poor ventilation, said Dr. Babak Javid, a physician-scientist at the University of California, San Francisco. The risk on other forms of transportation varies.
Dr. Vivek Cherian, an internal medicine physician in Elk Grove, echoed that sentiment.
"When you’re actually onboard the plane, the doors are closed, air is going through the HEPA filters, you’re actually quite safe on the plane," he said. "It’s more of the process of getting to the plane, going through the TSA checkpoint, traveling through the airport, that’s really where the concern is. And of course, when you’re on public transportation, like a bus, the concern is all the time.”
Dr. David Dowdy, an infectious-disease epidemiologist at Johns Hopkins Bloomberg School of Public Health, said planes can carry the virus from place to place, but that we should be focusing more on big indoor events such as concerts and sporting events — even large weddings —where people get together and talk, shout and sing.
"The fact of the matter is that we have no evidence that it is okay to do this," Landon said. "And I can tell you for certain there will be people who get COVID on planes who wouldn't have gotten COVID on planes if everyone was masked and there will be people who get COVID on buses."