# How long can a cold virus be infectious? **URL:** \ **Category:** Factual Questions\ **Created:** [May 16, 2002, 2:13pm UTC](https://boards.straightdope.com/t/how-long-can-a-cold-virus-be-infectious/109387 "2002-05-16T14:13:32Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![bernse](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@bernse](https://boards.straightdope.com/u/bernse)\ **Post date:** [May 16, 2002, 2:13pm UTC](https://boards.straightdope.com/t/how-long-can-a-cold-virus-be-infectious/109387/1 "2002-05-16T14:13:32Z")
Say I have a cold. I sneeze and cover my mouth. A minute later go out the door, turning the doorknob with my cold-virus infested hands. How long (ballpark) would the virus last on the doorknob? And when I mean “last,” I mean being able to infect someone else who opens the door and puts their hand in their mouth or something. Thanks ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [May 16, 2002, 3:32pm UTC](https://boards.straightdope.com/t/how-long-can-a-cold-virus-be-infectious/109387/2 "2002-05-16T15:32:20Z")
Up to three hours, according to the National Institute of Allergy and Infectious Diseases [fact sheet](http://www.niaid.nih.gov/factsheets/cold.htm). What’s more important is the vehicle for transmission. Did you leave a big glob of snot on the doorknob when you grabbed it? ---
**Author:** ![bernse](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@bernse](https://boards.straightdope.com/u/bernse)\ **Post date:** [May 16, 2002, 4:12pm UTC](https://boards.straightdope.com/t/how-long-can-a-cold-virus-be-infectious/109387/3 "2002-05-16T16:12:43Z")
> [@](#): > > Did you leave a big glob of snot on the doorknob when you grabbed it? Heh. Not me. Almost everyone at my business is sick but me. I think I’ll just lock myself in my office all day. Sounds like its the safest thing for me to do! 😉