We’ve all presumably been hand washing since we were children, but we may not know why or what the best method is.

It’s such an important task that in the developing world, the campaign to encourage hand washing has intensified in recent years. In 2008, the first-ever Global Handwashing Day took place, in conjunction with the United Nations’ celebration of the International Year of Sanitation, according to the World Health Organization. The event will take place again this year on Oct. 15.

Why hand washing can’t be skipped

So just why is hand washing so important? Well, it’s the best way to prevent infection and illness, according to the Centers for Disease Control and Prevention (CDC). Studies have shown that it reduces the rate of illness, particularly among children, and as a result lowers absenteeism at schools. That’s because washing one’s hands helps prevent the spread of colds, the flu, gastro-intestinal viruses and other infections.

Washing our hands is critical in public places such as schools, hospitals, daycare facilities and offices. Indeed, the role of hands in the transmission of hospital infections is well-known. And germs gather in so many of the places we touch: doorknobs, computer keyboards, ATMs, etc.

When to wash your hands

Okay, so now we know why hand washing is important but when is it absolutely necessary?

Everyone should be sure to wash their hands before they eat, after they use the bathroom and when they’ve been in contact with animals or animal habitats. They also should wash their hands after handling uncooked meat, poultry and eggs; after changing diapers; and after coughing, sneezing or blowing one’s nose.

How to wash hands properly

Hand washing is a basic human activity. But that doesn’t mean we can’t refine our technique.

First wet your hands with clean running water and then cover them with soap. If possible, use warm water to wash your hands.

Rub your hands together so you work up a good lather and be sure to cover the whole surface of your hands, front and back, and the spaces in between your fingers.

To give your hands a good scrub, continuing rubbing them together for about 15 to 20 seconds. According to the CDC, that’s the same amount of time it takes to sing “Happy Birthday” twice.

When you’ve finished lathering, rinse your hands well under running water. You can use a dryer or a paper towel to dry your hands, and if possible, turn off the faucet with a paper towel rather than your hands. WHO recommends that hospitals have facilities where the faucets are hands-free.

Using hand sanitizers

If you find yourself in a place where soap and clean water are not readily available, you can use an alcohol-based hand sanitizer instead. The CDC recommends ethanol alcohol-based hand sanitizers in gel form that have a concentration of at least 60 percent alcohol. These rubs dramatically reduce the number of germs on our skin and work quickly.

If you’re using a sanitizer, squeeze some into the palm of your hand and then rub your hands together. Be sure to rub the gel all over your hands and fingers until they are dry.

Drawbacks to using hand sanitizers

Alcohol-based hand sanitizers do not appear to have any serious side effects but experts say washing hands with soap and water is still better. The CDC says hand sanitizers are not a substitute for soap and water unless you’re in a place where those things are simply not available. Why? Because hand sanitizers don’t kill all the germs found on hands.

Experts also say it’s critical to use hand sanitizers that are more than 60 percent alcohol. Rubs with a 40 percent alcohol concentration, for example, are not considered as effective at killing the germs found on hands. Alcohol is also less effective at cleaning up bodily fluids.

Parents need to be cognizant that hand sanitizers contain a large amount of alcohol so they should be careful to prevent accidental (or intentional, in the case of older children) ingestion.

For more information, visit the CDC's hand washing webpage.

See also:

Prevent germ spread

Do you have more hand washing tips? Leave them in the comments below.

Hand washing: The hows and the whys
Hand washing. Learn why hand washing is so important and how to do it properly