Here’s a new travel health strategy: try to stay at least two seats away from that coughing, sniffling guy on the plane if you want to avoid getting sick.

Researchers at Emory University and the Georgia Institute of Technology who studied transmission of airborne illnesses on planes concluded that the most dangerous proximity to a sick passenger is within two seats laterally and one row in front or behind. Beyond about a meter radius, it’s unlikely that you’ll catch whatever it is that ails a fellow traveller.

“We found that direct disease transmission outside of the one-meter area of an infected passenger is unlikely,” explained Howard Weiss, PhD, a co-author of the study and a professor in the School of Mathematics at Georgia Tech.

Disease transmission on aircraft is limited by the fact that passenger movement tends to be restricted, researchers found.

“We now know a lot about how passengers move around on flights,” said researcher Vicki Hertzberg, PhD, professor at Emory University’s Nell Hodgson Woodruff School of Nursing. “For instance, around 40 per cent of passengers never leave their seats, another 40 per cent get up once during the flight, and 20 per cent get up two or more times. Proximity to the aisle was also associated with movement. About 80 per cent of passengers in aisle seats got up during flights, in comparison to 60 per cent of passengers in middle seats and 40 percent in window seats. Passengers who leave their seats are up for an average of five minutes.”

Experts note that even if you’re not seated close to an ill person, you can still get sick from germs left on surfaces, such as in the lavatory or on overhead bins.  “Passengers and flight crews can eliminate this risk of indirect transmission by exercising hand hygiene and keeping their hands away from their nose and eyes,” advised Weiss.

Past reports also have suggested that the policy of boarding aircraft from back to front also can help spread disease by forcing passengers to stand in aisles for extended periods of time.

The study was published in the Proceedings of the National Academy of Sciences.