【Taste of Future Sister-in-law】

Air travel is Taste of Future Sister-in-lawoften depicted as a spreader of diseases around the world, given that it squeezes lots of people into a small space. However, a new study shows that you're not likely to get the flu from a passenger seated more than 1 meter, or 3.3 feet, away from you.

The study, published Monday in the Proceedings of the National Academy of Sciences, claims to be the first to rigorously test the spread of viruses — specifically influenza — that are transmitted via large droplets, such as when an infected person coughs or sneezes.

Researchers from Emory University, the Georgia Institute of Technology, and Boeing employed teams of observers in pairs, sitting every five rows down in economy class in single-aisle aircraft during 10 transcontinental flights in 2012 and 2013. These observers watched and recorded the movements of passengers during the flight using an iPad app.

The study used the movement of each passenger to simulate the spread of influenza virus from a passenger seated in the mid-cabin (seat 14C, to be exact), and an infectious crew member. The researchers developed a new model of the network of contacts passengers and crew members had with one another, as well as a simulation model of disease spread, to find out how many additional people would get sick while on typical flights that last between 4 and 5 hours.

The results were surprising. On average, an infectious passenger seated in the mid-cabin had the potential to infect an additional 0.7 additional people per flight.

However, if an infectious crew member chose not to stay home, and did not take medication to limit their coughing, then that infectious crew member would infect an additional 4.6 passengers per flight, the study found.

"Our model simulations yield that an infected flight attendant could infect several passengers, and we quantify this. This provides additional support for the policy of preventing crew members from working when sick," said study lead author Vicki Stover Hertzberg, of Emory University.

The study found that people sitting in window seats who did not get up to go use the restroom or check the overhead bin had far less exposure to infectious passengers than people sitting at the aisle, or people who spent time in line waiting for the restroom at the back of the cabin, for example. So, come next flu season, you might want to pick a window seat and avoid getting up.

"If they select the window seat to minimize those exposures, they also need to stay there (i.e., don’t move). When they move, they increase their exposures," Hertzberg said.

The study has some significant limitations. It does not apply to illnesses transmitted via smaller particles known as aerosols, which include tuberculosis, measles, and other dangerous pathogens. "These tiny particles need not fall within a meter of the infected passenger," Hertzberg said. "They can stay suspended in the cabin air for long periods of time, be taken up by air recirculation systems, etc."

The study also didn't quantify the risk of getting sick from viruses located on air cabin surfaces, such as an armrest or seatbelt. And it doesn’t apply to twin-aisle, larger aircraft used on long-haul flights, or quick shuttle flights, such as from Boston to Washington, D.C.

The bottom line, though, said study co-author Howard Weiss, of Georgia Tech, is that "If you practice good hand hygiene, keep your hands away from your face, and if you are seated further away than a meter from an infected passenger, you are unlikely to get infected by influenza during an 4 to 5 hour flight."

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