We have been teaching kids this for years: Washing your hands can help protect you from nasty germs. But a quick wash won't do. You need to scrub them for at least 20 seconds.
Grandma was right: If you want to prevent the spread of viruses, wash your hands.
But how long do we need to scrub? Preschoolers know the answer, and they sing a silly song or two to help them while away the 20 seconds that experts recommend.
Karen Robison, a preschool teacher at the Learning Center for Young Children in Kensington, Md., leads her charges in singing the entire A-B-C song. It lasts about 20 seconds.
LCYC Director Karen Murphy says the singing works: "What we do do is certainly quite effective."
The children wash their hands three times each day. "It's part of their routine," she says.
But it's not good enough to run your hands under water and pat the soap absentmindedly.
Pathogens hide in crevices and crannies. On our bodies, the backs of the fingernails can harbor germs, explains Rob Donofrio of the National Sanitation Foundation International, a nonprofit group that aims to protect public health by certifying products and setting safety standards for risk management that are recognized internationally.
Donofrio's job is to help educate people about where germs hide. He demonstrates how to scrub the fingernails —down where the skin meets the nail, using a small brush with bristles, like a toothbrush.
"I'm scubbing my fingers for about 10 seconds or so — and just going horizontally across the nails," Donofrio says as he shows off his technique.
All the proper steps of handwashing, and why it's so important, are depicted in colorful cartoon form on the NSF International site. "Keep Influenza Enzo on the run!" one cartoon about handwashing admonishes.
But if adults want to reinforce the good habit of 20 seconds of washing, perhaps we should come up with our own song, because the A-B-Cs and cartoons can get tiresome.
NPR's reporters were quick to offer their suggestions: The chorus of Neil Diamond's "Sweet Caroline" is about the right length. Maybe the guitar riff from "Layla" by Eric Clapton, or how about that famous bridge in Queen's "Bohemian Rhapsody" about how "we will not let you go"?
For those more inclined to the theater, the first six lines of Lady MacBeth's "Out, Damned Spot, Out" soliloquy clocks in at 22 seconds.
You can vote for your favorite below.
Whatever option you choose, make sure it lasts 20 seconds and invest in a nail brush to help give those flu germs the slip.