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Flu (Influenza) Transmission

How Flu Spreads

  • Coughing and Sneezing

    People with flu can spread it to others up to about six feet away. Flu viruses spread mainly through tiny droplets made when people with flu cough, sneeze, or talk. These droplets can land in the mouths or noses of people who are nearby or be inhaled into the lungs.
    photo of woman sneezing

    A woman covers her nose and mouth when sneezing on an airplane.
    Credit: iStockPhoto

  • Surfaces and Objects

    People can also be exposed to flu by touching a surface or object that has flu virus on it and then touching their mouth, eyes, or nose. Studies have shown that human flu viruses generally can survive on surfaces between two and eight hours.

Hand washing with soap and warm water can help people avoid becoming infected by flu virus. If soap and water are not available, an alcohol-based hand rub may be substituted. Linens, eating utensils, and dishes used by people who are sick should not be shared without washing thoroughly first.

The Flu Is Contagious

You may be able to pass on the flu to someone else before you even know you are sick—as well as while you are sick. Most healthy adults can infect others beginning one day before symptoms develop and up to a week after becoming sick. Young children and people with weakened immune systems might be able to infect others for an even longer time. To avoid spreading the flu, the Centers for Disease Control and Prevention recommends that ill people stay home for at least 24 hours after fever is gone.

Last Updated November 16, 2012