The kids in Jon Nessan's fourth-grade classroom know what you're supposed to do when you feel a tickle in your throat: Cough in your elbow.
"They've been doing it since kindergarten; it's an automatic reflex for them," says Nessan, a teacher at Meridian Park public elementary school in the Shoreline section of Seattle.
Over the past decade or so, schools and day-care centers around the country have gradually adopted the technique as a way to ward off colds, flu, whooping cough and other easily transmitted bugs. It's been replacing the traditional cover-your-mouth-with-your-hands-or-a-tissue approach that has long been considered the polite and most sanitary technique.
The reasons are fairly obvious -- when you use your hands to block a cough or sneeze, the germs stay here. And your hands can then spread the germs to doorknobs, desks, chairs and anything else you touch.
So one solution is to cough and sneeze in your elbow or on your sleeve, instead.
"As long as you don't wipe your face with your elbow you basically decrease your chances of transmission," says Dr. Craig Rubens, an expert on pediatric infectious diseases at the University of Washington.
The technique is now recommended by the U.S. Centers for Disease Control and Prevention and the American Academy of Pediatrics, which both pass out health information to schools and public health officials around the country. The CDC distributes posters showing ways to prevent the spread of germs -- including an illustration of a child with his elbow tucked beneath his nose.
Over the past 20 or so years, researchers have confirmed that viruses can remain viable for several hours once they land on a surface like a doorknob or chair. A sneeze or cough may send viral material or bacteria out into the air, but gravity quickly sends it to the ground. Germs on the hands can be easily transferred to other surfaces, and are then passed on to other people when their hands touch those surfaces.
"I think people still don't understand how important hands are," says Rubens, referring to the transmission of germs.
Along with government agencies, there are also freelance proselytizers of elbow coughing, elbow sneezing and other germ-fighting techniques.
Dr. William Sawyer, a family practice physician in Cincinnati, has created "Henry the Hand," a sort of good-hygiene crusader. Henry, in the form of a cartoon or costumed character, has met more than 150,000 health-care providers and more than 110,000 students around the country, by Sawyer's count.
Hand hygiene has the potential to change the world, Sawyer proclaims. "It's the latest breakthrough in biotech and it didn't cost anything."
Sawyer advocates the "four principles" of hand awareness. Two of them are familiar to nearly everyone -- wash your hands before eating, and don't put your fingers in your eyes, nose or mouth. But the other two tell kids to sneeze and cough into their elbows, instead of their hands.
"It absolutely has a huge impact," Sawyer says. He notes that "Henry the Hand" materials have been ordered and downloaded by health care professionals in Europe, Africa and India, among other places.
"I wouldn't say we'd have no flu," Sawyer says, "But it would certainly be decreased dramatically."