I travel on planes a lot (which I love). Lately, as concerns of the spread of COVID-19 are on everyone’s mind, I’ve been wondering how exposed we are to germs when we fly. If someone is sick on the plane, is everyone on the plane going to catch it?

This question was answered by a recent study conducted by researchers at Emory and Georgia Tech and published in the Proceedings of the National Academy of Sciences in 2018. The intrepid researchers collected their data on 10 cross-country flights during flu season and chronicled the movement of passengers and crew and collected hundreds of germ samples around the cabins. Based on this data they built computer models of disease transmission.

Their conclusion: flying on a plane doesn’t expose you to everyone’s germs. Rather, the “results indicate there is low probability of direct transmission to passengers not seated in close proximity to an infectious passenger.”

More specifically, if you sit within a meter or so of a contagious passenger you have a good chance of being infected. But, if you are beyond that range, your chance of infection is quite low. So, it is those people sitting in the same row, the row behind and the row in front of a sick person that have the greatest chance of infection. Outside that three-row area, the chance of exposure is low.

The number of other travelers we come in close contact with also matters. The more people we are exposed to the greater the chance of infection. The study found that the window seats have less chance of infection than aisle seats because people in aisle seats have more interaction with people walking up and down the aisle. Only 43% of window seat occupants left their seats during flight compared to 80% of aisle seat passengers. Aisle seat passengers averaged contact with 64 other passengers while window seat occupants averaged only 12.

In sum, if there are a few contagious people on the plane your overall chance of getting infected is not very high unless you sit in close proximity or come in contact with them as you or they walk to the lavatory.