How to Avoid Catching the Flu on a Plane

The chances of the average passenger catching the flu on a flight is relatively slim, according to new research which has pinpointed those most at risk of falling ill.

Scientists at Emory University investigated the likelihood of catching common respiratory infections in air cabins by analyzing how passengers and crew moved during short-haul flights. Sitting one or two seats away from a person with the flu, or in the row in front or behind, has an 80% risk of contracting the respiratory illness.

But for everyone else, the risk was less than 3%, according to the study.

"What we showed is that outside this perimeter there is very little probability of becoming infected on an airplane," Vicki Hertzberg, director of Emory's Center for Nursing Data Science, told The Guardian. "You don't have to worry about the coughing coming from the person five rows behind you," added Hertzberg, whose research was published in the journal PNAS.

Researchers traveled on 10 domestic flights lasting between 3.5 and five hours, documenting the movements of some 1,540 passengers and 41 cabin crew members, and testing 228 samples from the air and hard surfaces for 18 common respiratory viruses. They all came back negative even though it was the height of flu season.

Hertzberg's team calculated the risk of infection according to the worst-case scenario, based on a report published in the Proceedings of the National Academy of Sciences: A passenger with the flu would infect others at a rate of 0.018 per minute of contact. Researchers also noted that the model only took into account viruses spread via coughs and sneezes, and not those that may lurk in the cabin air.

Related: Here's How the Flu Attacks Your Body—and Why It's so Painful

Further research is needed to understand whether the findings also relate to long-haul flights, where passengers and crew members are more likely to move around, the researchers said.

"The weakness of the analysis is that airflow within the cabin of an airplane is very difficult to simulate, so long-range infections via that route remain an open issue," Derek Gatherer of the Faculty of Health and Medicine at Lancaster University, and lead educator on the FutureLearn course "Influenza: How the flu spreads and evolves," told Newsweek.

Christopher O'Kane, a lecturer in biomedical science at Anglia Ruskin University, highlighted that although viruses cannot replicate outside of the infected individual, they can remain dormant for 24 to 48 hours on hard surfaces such as the plastic interior of an aircraft.

While the reduced humidity inside an aircraft reduces the chances a virus will survive, he said, the question remains how many more individuals may become sick on the next flight if infected surfaces aren't cleaned.

"In this study, the investigators did not find any viruses on the surfaces and the airlines states that hard surfaces are disinfected after the plane 'overnights'. The lack of an initial presence of a virus being spread limits the conclusion that can be made from this observation," he told Newsweek.

Air passengers hoping to avoid catching common respiratory ailments are advised to stay in their seats to minimize transmission opportunities, and avoid touching anything a flight attendant who appears to be ill passes to them, Gatherer said.

But on long-haul flights, moving and walking in order to avoid deep vein thrombosis trumps the temptation to stay seated in order to avoid the flu, he argued.

"For added protection when traveling, my advice is to carry alcohol wipes or a hand gel. Wipe down the surfaces you will be touching and always wash your hands with soap and water between using the hand gel and before eating," said O'Kane.

The responsibility to prevent the spread of the flue lies with all of us, he continued, regardless of where we are. "From covering our mouth and nose when coughing and sneezing, and washing our hands regularly and especially before meals, we significantly reduce our chances of picking up a virus," he added.