The CDC credits Dr. Ignaz Semmelweis as being the first to demonstrate the merits of hand washing. Semmelweis worked 150 years ago at a maternity hospital in Vienna.
He noticed that many of the dying patients had been treated by students who had been working on corpses during an anatomy class before starting their rounds - inadvertently spreading germs from the corpses to the patients.
In an experiment, Semmelweis insisted students wash their hands before treating mothers; he reported a decline in the number of deaths.
Taken for granted
A recent study suggests that people aren't washing their hands as often as they say they do - at least in public restrooms.
A set of surveys conducted by the American Society for Microbiology found that while 92 percent of people say they wash their hands in public restrooms, only 77 percent of people were observed doing so.
Conducted in 2007, the study observed the behavior of 6,076 adults in public bathrooms in Atlanta, Chicago, New York and San Francisco and was compared against the results of a telephone study.
"Those results are pretty consistent year after year," said Barbara Hyde, spokeswoman for American Society for Microbiology.
Master the basics
Part of Morrisey's job is to show new hospital employees how to properly wash their hands - tips she said could apply to all Americans.
"We're kind of getting back to the ABCs and emphasizing the importance of hand washing. ... I don't think people realize that your hands are dirty, because you can't see the bacteria," Morrisey said.
At home or otherwise, Morrisey offers a few suggestions:
1. Wet your hands with running water and apply soap.
Morrisey said wetting your hands first helps to generate a good lather with the soap - something that might not go over as well, say, if you did it in reverse order.
2. Rub hands together to make a lather
This is the part people tend to flub, Morrisey said. Some people think the entire hand-washing episode - start to finish - is supposed to take 15 seconds. This is wrong. The rule of thumb is to start the 15 seconds once you have developed lather on your hands. Fifteen seconds is about the time it takes to sing "Happy Birthday" twice, Morrisey said.
If you were a surgeon, you'd be lathering for five minutes - taking care to wash the front, sides and back of each finger, your palms, the back of your hand, then washing down to your elbow and then two inches past that.
3. Rinse hands well under running water.
This is where another hand washing faux pas occurs. "You want to rinse (with) finger tips down," Morrisey said.
Otherwise, the germs you spent the last 15 seconds suspending in soapsuds will inch back toward your wrists.
4. Dry your hands using a paper towel.
Use your paper towel to turn off the faucet, and, if you're in a public place, use it to open up the door so that your clean hands are not picking up fresh bathroom germs.
5. But I'm not around soap and water. What do I do?
Morrisey says hand sanitizers are effective germ killers, whose effects last beyond the initial hand washing. The CDC recommends using a hand sanitizer with at least 60 percent alcohol content. But Morrisey and the CDC note that the hand sanitizers are designed to kill germs; they don't remove visible soil. So if you can see the dirt on your hands, you'll need to wash with soap and water.