As international travelers help swine flu hopscotch across the globe, the potential pandemic sharpens a paranoia familiar to even the most casual flier. Isn’t sitting on a plane for hours, squished next to strangers and breathing the same air, a surefire recipe for getting sick later?
That common belief was underscored late last week by none other than Vice President Joe Biden. “When one person sneezes it goes all the way through the aircraft,” he declared on NBC’s “Today” show.
Air Travel Sickness Bags Aren't Enough
And heightened public concern was evident in how quickly a flight from Munich to Washington was diverted to Boston Friday to remove a passenger who said she felt ill. She was treated at a local hospital and later released.
It’s no surprise that people worry about getting sick every time they fly. Not only do planes ferry sick people to new locales where diseases can gain a foothold, but they put passengers in what seems like a hotbed of germs, with no way out.
“Whenever you put that many people that close together, the issue of disease transmission is going to be of concern,” said Byron Jones, a mechanical engineer at Kansas State University who studies airplane ventilation in his laboratory, which includes 11 rows of a Boeing 767 airline cabin.
But don’t despair if the guy four rows ahead sneezes. Scientific studies show that contrary to popular belief, germs and other contaminants don’t travel the length of the plane, infecting everyone. And there are steps you can take to minimize your risk of catching something.
“We have close to 2 billion people traveling by air annually, and we don’t hear of these huge outbreaks as a result of the air travel,” said Dr. Mark Gendreau, senior staff physician at Lahey Clinic and author of a recent study on medical issues on flights in the medical journal The Lancet.
The risk of onboard transmission of infection is mainly restricted to individuals with either personal contact, or seated within two rows of an infected passenger on flights longer than eight hours, according to Gendreau’s 2005 study that reviewed the available literature on infectious disease on planes.
In his new study, Gendreau reviewed the literature on diseases that spread on planes, finding incidents where everything from flu to measles to food poisoning have become mile-high contagions. But it’s important to remember, he said, that the cabin ventilation systems have been designed to minimize risk. There is evidence that when they are working properly, they do just that.
Typically, airplane air – about half from outside and half recycled after being passed through filters – enters at the top of the cabin. From there, the ventilation system keeps it from flowing forward and backward in the plane, limiting it mostly to the immediate row, before exiting through grilles in the cabin floor.
One study illustrates the importance of ventilation by showing what happens when it’s not in operation: On a 1979 flight, nearly three quarters of the passengers contracted influenza within 72 hours. The reason, researchers found, was probably because passengers sat on board for three hours with a broken ventilation system while repairs were done.
Other studies seem to show that our fears of catching cold on a plane may be overblown. A study of 155 travelers found they were probably infected before their flights: An analysis of the bacteria and viruses they harbored showed that few travelers had the same pathogens, and there were no links between pathogens and specific airports.
Plane infection has been studied sporadically, and often when outbreaks occur. But the issue is attracting more scientific interest. This fall, a two-day symposium is planned on the transmission of disease in airports and on planes by the National Academy of Sciences.
Studies have shown that numerous supplements do not prevent the flu. Last year, the maker of the popular supplement Airborne paid $23.3 million in a class action lawsuit, for making claims without sufficient evidence that the product could prevent colds.
But there are things passengers can do to protect themselves.
What’s most important on the plane is the same as on the ground. Passengers should be careful not to touch their eyes, nose, or mouth during the flight and to wash their hands or use a sanitizing gel.
Infection occurs when viruses or bacteria are sprayed from infected people in droplets from a cough or sneeze. The pathogens can then be picked up when passengers touch their tray table or the arm of their seat, and then rub their eye.
People should also be sure to stay hydrated in the arid cabin environment.
Vice President Joe Biden says you can get swine flu on a plane
“The aircraft cabin is notoriously dry; it has poor humidity and the way it gets its humidity is through the breath of cabin occupants,” Gendreau said. “If you can keep your mucus membranes very moist, that’s our first natural barrier.”
Then there is a somewhat more creative theory of how to prevent getting sick on board by using the nozzle that sprays a jet of cool air onto passengers.
Gendreau said he turns the nozzle to a medium air flow and points it in front of his “face space,” with the idea of creating turbulence that could jettison any stray microbes.
Jones, the mechanical engineer at Kansas State, is officially skeptical about whether directing the nozzle’s air flow is an effective way to deter disease, calling it a bit of “false security.” But he admitted that he uses the same technique when someone on the plane is sneezing or coughing.
He also said that in picking a seat, common sense prevails.
“Nobody likes that center seat – you’ve got people on both sides of you,” Jones said. “There’s no magic there.”
In general, people shouldn’t fly when they are sick, whether it is an infectious disease or a recent surgery.
Gendreau said that he frequently writes notes to the airlines for his patients when it is not appropriate for them to fly, and that people are usually given vouchers to fly at a later time.
Dr. Richard Besser, acting director of the US Centers for Disease Control and Prevention, said that people who are sick or experiencing flu-like symptoms should not be flying.
But even in the throes of swine flu, healthy people have no reason to avoid flying.
“I think flying is safe, getting on the subway is safe,” Besser said. “People should go out and live their lives.”