How Do You Catch a Cold or the Flu?

Medically Reviewed by Hansa D. Bhargava, MD on January 20, 2017
1 min read

At the first sign of a cold or flu, you may wonder how it happened -- especially if you've taken steps to avoid germs. Here's exactly how you get sick, and what you need to know to protect yourself next time.

  • Viruses spread through tiny droplets in the air that are released when a sick person sneezes, coughs, or blows their nose.
  • You can get sick if you touch your nose, eyes, or mouth after you have touched something contaminated by the virus, such as a toy, countertop, or doorknob. Viruses can live on those objects for up to 2 days.
  • If you come in contact with cold or flu germs, your chance of getting sick isn’t 100%. It depends on when the other person was infected, and how many viral particles are contained in the droplets.
  • People are most contagious during the first 2 to 3 days of a cold. A cold is most often not contagious after the first week.
  • People who have the flu may pass it on to others 1 day before symptoms start and up to 5 to 7 days after getting sick, so they may spread the flu before they even know they are sick.