A federal judge's rejection of the nation's mask mandate for travelers taking public transportation set off a flurry of responses.
Some Americans cheered midflight and took their masks off when they found out Judge Kathryn Kimball Mizelle's April 18 ruling meant they were no longer required to wear them, The New York Times reports.
But some people who travel with young children not yet eligible for COVID-19 vaccination and those at high risk for severe illness met the announcement with worry and fear.
Many health experts also expressed concern about the timing of the loosened restrictions, which come as COVID-19 cases and hospitalizations are rising nationwide. The new recommendations put the onus on individuals to determine how to best protect themselves. Many are asking if wearing a mask works if no one else around you is wearing one.
The CDC still recommends wearing a mask, and urged the U.S. Justice Department to appeal the April 18 ruling.
"It is CDC's continuing assessment that at this time an order requiring masking in the indoor transportation corridor remains necessary for the public health," the agency said April 20, adding that "wearing masks is most beneficial in crowded or poorly ventilated locations, such as the transportation corridor."
Many infectious disease experts and other health experts have said they will continue to wear a mask, regardless of whether passengers around them are masked or not.
"You can quote me on this: I'm going to continue to wear an N95 mask," said David Freeman, MD, professor emeritus of infectious diseases at the University of Alabama at Birmingham. "No question. You have no idea who's on a plane," he told The Washington Post.
Plenty of factors play into the level of protection provided from wearing a mask — the type of mask, duration of exposure to an infected person and the mode of transportation the mask-wearer is using to name a few. While some environments may pose higher risks than others, a number of studies have indicated masks offer at least some degree of protection to the wearer.
One study published Dec. 2 in the peer-reviewed journal PNAS found someone wearing a surgical mask had up to a 90 percent chance of contracting COVID-19 after speaking with an unmasked, infected person for half an hour. This risk dropped to 20 percent after a full hour if the person was wearing a respirator and just 0.4 percent if both people were wearing respirators.
Universal masking is the gold standard in infection control, as it both contains the wearer's germs and filters out other people's.
That said, "one-way masking is definitely better than nothing," Emily Sickbert-Bennett, PhD, director of infection prevention at UNC Medical Center in Chapel Hill, N.C., told Time.
Wearing a good-fitting, high-quality mask correctly offers the wearer a high degree of protection, even if other people in proximity aren't masked, according to Scott Gottlieb, MD, former FDA commissioner and current Pfizer board member.
"One-way masking does work," he said during an interview on CNBC's Squawk Box. "So people who feel vulnerable, if they continue to do that, are going to be able to protect themselves in that setting even if other people aren't wearing masks."