How Do We Catch the Flu?

(Image credit: Dreamstime)

If you want to be one of the 20 percent of Americans who catch the flu this season, shake hands with a lot of sick people.

Sickly folk are contagious for a long time. An adult can spread the virus one day before and three to seven days after symptoms show. Kids are contagious for even longer periods of time. Although you can steer clear of those that sniffle , some infected individuals show no symptoms and can still spread the virus to others.

Most commonly, the virus travels through the air in liquid droplets from coughs and sneezes . Viruses prefer the wintry conditions of cold air with low humidity. In humid air, the droplets grow heavy with water and fall to the ground—or to other surfaces.

To avoid the flu altogether, your best shot is to move to the tropics. Flu season is virtually nonexistent in those hot and humid conditions.

If you do fall ill, you can avoid transmitting the flu by following these steps from Harvard Medical School.

  • Always cover your mouth and nose when you sneeze or cough.
  • Throw used tissues away immediately.
  • Wash your hands often , especially after you sneeze, cough, or touch your eyes, nose, or mouth.
  • Keep your distance from others — don’t kiss, hug, or stand so close to someone that saliva might get on them when you talk.
  • Make sure someone is disinfecting household surfaces and items frequently, including children’s toys.

Some of these tips, especially the hand-washing, are also useful prevention measures if you're feeling just fine.

Got a question? Email it to Life's Little Mysteries and we'll find an expert who can crack it.

Follow Life's Little Mysteries on Twitter @llmysteries. We're also on Facebook & Google+.

Corey Binns lives in Northern California and writes about science, health, parenting, and social change. In addition to writing for Live Science, she's contributed to publications including Popular Science,, Scholastic, and the Stanford Social Innovation Review as well as others. She's also produced stories for NPR’s Science Friday and Sundance Channel. She studied biology at Brown University and earned a Master's degree in science journalism from NYU. The Association of Health Care Journalists named her a Centers for Disease Control and Prevention Health Journalism Fellow in 2009. She has chased tornadoes and lived to tell the tale.