Pathogens on a plane: How to stay healthy in flight

If you want to cut your risk of catching the flu on your next flight, pick a window seat and stay put.

That's a key take-home message of a study published Monday in the Proceedings of the National Academy of Sciences. "I have always chosen window seats," says Vicki Hertzberg, a biostatistician at Emory University, who co-led the research with scientists at The Boeing Co. "But after this study, I have stopped moving around as much on flights."

People in window seats come into contact with fewer passengers, Hertzberg and her team found, because they leave their seats less often than those sitting near the aisle. And they are farther away from the action in the aisle, with its potentially coughing and otherwise germy passersby.

"So the window seats are a little less risky than the aisle seats," Hertzberg says.

The finding comes from an effort to model how pathogens spread through the air in planes. To do that, Hertzberg and her colleagues created what she calls "Fantasy Flights."

"We were working on the study while it was fantasy football time," she says. "So we started to call it that."

It's an appropriate name because in essence, the Fantasy Flights work in a similar way to a game of fantasy football: Hertzberg and her team created simulations of people moving around the cabin during a three- to five-hour transcontinental flight.

"Then in the simulations, we could make a passenger sick — like the passenger in seat 14C — and see what's the probability of somebody coming into contact with the sick person," Hertzberg says.

Overall, passengers had the greatest chance of catching the bug when they sat right next to the sick passenger or in the row in front of or behind the sick person.

"There was a perimeter around the person with increased risk," Hertzberg says. "Everywhere else, the risk of getting sick was minimal."

Hertzberg and her team created the computer simulations by documenting how people moved around the cabins on 10 transcontinental flights, from Atlanta to the West Coast.

Their findings are consistent with previous studies looking at how real viruses and bacterial pathogens spread on planes. In general, sitting near a sick person puts you at the highest risk. But the size of the "transmission zone" depends on the specific pathogen and how it transmits.

For instance, there's a chance you could catch tuberculosis when you sit within two rows of someone infected with TB and the flight is longer than eight hours.

And for SARS, that transmission zone very likely extends to at least three rows around the sick passenger — or perhaps up to seven rows.

Of course, pathogens don't just spread through the air. They can also land on surfaces — like the armrest or headrest — and survive there for hours, even days.

"When you look at most infectious diseases, the overwhelming majority are transmitted when you touch a contaminated surface," says Dr. Mark Gendreau, who specializes in aviation medicine at Lahey Medical Center in Peabody, Mass. "You grab the doorknob of the airplane bathroom, and then touch your eyes, nose or mouth."

"But we're not all doomed to get sick after a plane flight," Gendreau adds. "You can change behaviors when you're traveling and substantially reduce the risk of catching anything."

First off, keep your hands microbe-free. "I recommend bringing aboard a sanitizing gel with 60 percent alcohol," he says. "Before you eat or drink, sanitize your hands."

And don't forget to use the sanitizer after you wash your hands in the bathroom's sink, Gendreau recommends. The water in airplanes has a dirty track record.

In 2004, the Environmental Protection Agency found high levels of fecal bacteria in the drinking water of 15 of the 327 planes it tested. Then in 2009, the agency set forth new guidelines for airlines to test their water. Now the EPA says that water on the airplane is safe to drink if you don't have a suppressed immune system.

But Gendreau still wouldn't risk it. He wouldn't even brush his teeth with the water in an airplane bathroom. "I use bottled water," he says.

And if a person is coughing right next to you and the plane isn't jampacked, maybe just ask for another seat. Copyright 2019 NPR. To see more, visit https://www.npr.org.