Farmer 'N The Dell

A common piece of advice for avoiding getting sick is to avoid sick people. Seems fairly obvious, but what if you’re trapped on an airplane and someone on board is ill? Are you a sitting duck for disease?

The answer is not entirely straightforward. If you’re sitting next to a sick person, yes. You’re strapped in at 30,000 feet for the long haul. All those germs your seatmate are spewing out are heading your way. But what if someone is coughing ten rows ahead of you? Will you breathe those germs, too?

The answer is in the cabin air. Airlines mix fresh air from outside the airplane with recirculated air from inside to ventilate the cabin. The ratio is typically 50:50 but can vary to as much as 80% recirculated air, 20% fresh. Airline industry groups claim that this is a safe practice because the recirculated air is subjected to HEPA filtration, and cabin ventilation blows from the top of the plane to the cabin floor and not lengthwise from one end of the plane to the other. In other words, the ventilation system will not blow droplets from somebody’s cough  in Row 1 all the way to Row 30.

There are several concerns regarding this information, however. First of all, HEPA filtration removes most microscopic particles, but does not necessarily filter out small viruses like swine flu. This is alarming news when you consider that cabin air is recirculated thirty times during a one hour flight.   Second, there is evidence that despite the ventilation system, germs still do travel throughout the cabin. James Bennett, a research engineer for the National Institute of Occupational Safety and Health, has shown that within seconds of a person coughing, droplet germs spread outward with nearby passengers receiving the heftiest exposure. Within 15 minutes of the initial cough, germs can spread as far as ten rows away.

But do these facts mean that you’re doomed to be sick the minute you step on an airplane? Fortunately, the answer appears to be no. A  2005 research article by Dr. Mark Gendreau reports an increased risk of onboard transmission with close personal contact (e.g., your seatmate coughs near you) or being seated within 2 rows of a sick passenger on a flight lasting longer than 8 hours. This suggests that if you’re flying domestically and you’re not seated next to a sick person, you’re probably all right.

That being said, there are things you can do to protect yourself when you fly (since you never know who you’ll be seated with):

1) Don’t touch your eyes, nose, or mouth while in flight. Most flus and colds are spread by respiratory droplet, and you don’t know what microscopic germs are located on your tray table or arm rests.

2) Sanitize your hands with antimicrobial gel periodically.

3) Stay hydrated. Airlines purposely keep cabin air dry. Moist mucous membranes help protect you from germs. Drink water to avoid getting “dried out.”

4) Avoid the center seat, if you can.

5) Bring your own blanket and pillow.

6) If you’re forced to sit next to a sick person, the following is not proven, but some experts do it themselves: turn on the airblower in the panel above your head and direct the air stream into the space in front of your face. Some people believe that this will help blow germs away from you. Who knows?

7) Above all, if you’re sick, don’t fly. It reduces the risk to others.

Remember, nearly two billion people fly annually, and there are few if any reports of widespread outbreaks associated with flying. But that doesn’t mean you’re not at risk of catching something on a plane. Use the tips above to keep the skies friendly to your health.

This entry was posted on Saturday, October 24th, 2009 at 10:04 am and is filed under Health. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.