To guard yourself against the worst flu season in a decade, you’ve probably been taking extra care to stay far away from people who are coughing and sneezing. But that might not be enough, according to a new study, which found it may be possible to spread the flu just by breathing the same air as someone who is sick! Ugh.
“We found that flu cases contaminated the air around them with infectious virus just by breathing, without coughing or sneezing,” Dr. Donald Milton, M.D., Dr.P.H., professor of environmental health in the University of Maryland School of Public Health and lead researcher of the study, explains in a statement. “People with flu generate infectious aerosols (tiny droplets that stay suspended in the air for a long time) even when they are not coughing, and especially during the first days of illness. So when someone is coming down with influenza, they should go home and not remain in the workplace and infect others.”
Before this study, we didn’t know much about the amount and infectiousness of the flu virus lurking in our breath, according to the study’s authors. To learn more, they monitored 142 University of Maryland students who had confirmed cases of the flu. The students were asked to stick their faces into a machine — the aptly named Gesundheit II, which measures the droplets shed while breathing, talking, coughing or sneezing — for 30 minutes at a time. Each student did this on the first, second and third days after their symptoms began.
To every germaphobe’s dismay, the researchers found that 11 of the 23 samples that didn’t involve coughing (48 percent) contained flu matter, demonstrating that, yes, it’s theoretically possible to spread the flu just by breathing.
Interestingly, sneezing didn’t produce more flu matter in the samples, meaning that it doesn’t necessarily contribute to virus shedding as much as you might have thought. (Please don’t take that as an excuse not to cover your mouth while sneezing, though.)
Because the study, which was funded by the Centers for Disease Control and Prevention and the National Institutes of Health, didn’t track transmission, the researchers can’t confirm that the exhaled droplets would have given someone the flu. Nevertheless, Milton tells Time that the study suggests that “if that person next to you looks really sick, even if they’re not coughing, they can probably infect you.”
If future studies prove that these airborne droplets can transmit the flu, they could influence the way that public spaces are built and ventilated. For now? “The take-home message is to stay away from other people when you’re sick with flu-like symptoms, even if you’re not coughing,” Milton says.
So, please, if you’re feeling even remotely sick this flu season, do us all a favor and stay home!
Read more: 12 Not-So-Common Tips to Fend Off Cold and Flu