Internist Dr. James Steckelberg from Mayo Clinic answers this common question about the upcoming flu season:
Q: If someone has the flu or a cold and coughs into his hand and then touches a doorknob, how long can those germs live on that doorknob?
A: The length of time that cold or flu germs can survive outside the body on an environmental surface, such as a doorknob, varies greatly. But the suspected range is from a few seconds to 48 hours — depending on the specific virus and the type of surface.
Flu viruses live longer on surfaces than cold viruses do. Also, it’s generally believed that cold and flu viruses live longer on non-porous surfaces — such as plastic, metal or wood — than they do on porous surfaces — such as fabrics, skin or paper.
Although cold and flu viruses primarily spread from person-to-person contact, you can also become infected from contact with contaminated surfaces. The best way to avoid becoming infected with a cold or flu is to wash your hands frequently with soap and hot water or with an alcohol-based sanitizer. And don’t shake hands during flu season.
And then go clean your doorknobs . . .
Resources: Mayo Foundation for Medical Education and Research