The Medical Minute: Hand Washing Week: Clean hands lead to good health

December 05, 2006

By John Messmer
Penn State Family and Community Medicine
Penn State Milton S. Hershey Medical Center
Penn State College of Medicine

It's winter -- people with colds are everywhere we go. At work, school, stores, restaurants, the movies and just about any place people gather, the sounds of coughing and sneezing are the percussion accompaniment to seasonal melodies. Many people have the misconception that people contract colds from the germs they breathe, but the truth is, people literally "catch" cold viruses in our hands. Once on their hands, people infect themselves.

People with colds are four times more likely to have viruses on their hands than in their sneezes. Viruses are deposited on counters, cups, door knobs and so on where they can live for hours. When people shake hands with infected people or touch things they have touched, viruses may be picked up. By touching their nose or eyes, the viruses can infect them. Kissing someone or sipping from their cup is actually less likely to spread a cold than simply touching the nose since it takes 8,000 times fewer viruses to infect the nose than the mouth.

Hand washing has been shown to reduce significantly the chance of spreading cold viruses. Studies in elementary schools have demonstrated a 50-percent reduction in absenteeism with the introduction of a comprehensive hand-washing program.

Hands can carry other infections, too. Intestinal diseases from simple diarrhea to hepatitis A are reduced when food preparers wash their hands.

There's a technique to proper hand washing if it is to be effective. Germs and dirt adhere to skin oils and upper layers of skin. Vigorous rubbing loosens the dead skin cells. Soap does not kill germs; it keeps the germs and dirt suspended in water so they can be rinsed off. In fact, it's not necessary to try to kill germs with antibacterial soaps. To be effective, antibacterial soaps must stay in contact with the skin for several minutes, but good hand washing can be accomplished in 15-20 seconds.

When hands are not visibly dirty, alcohol-based sanitizers have been shown to kill pathologic bacteria in seconds without the drying effect of soap. They can be kept close at hand to eliminate walking to a sink. Research has shown significant reductions in illness in schools where hand sanitizers have been used because they can be kept in the classroom so sinks are not needed. Visible dirt should still be removed by washing, but hand sanitizers can eliminate germs that cause colds and other illnesses.

Although shaking hands is a standard custom in Western societies, people are rethinking its place in social and business interactions because it spreads viruses. The Centers for Disease Control is suggesting people cough or sneeze into the bend of the elbow to keep viruses off their hands. People can reduce their own risk of illness by learning not to touch their eyes or noses until after they have washed their hands thoroughly or used a skin sanitizer.

If clean is good, is it possible to be too clean? Yes -- studies in nurses show that too much cleaning which results in sore, chapped, broken skin will allow larger numbers and more serious germs to live on the skin.

So, it's not necessary to try to make hands germ-free, just clean enough. The Centers for Disease Control recommend hand washing before, during and after food preparation; before eating and after using the bathroom; after handling animals or their waste; when hands are visibly dirty and frequently when caring for a sick person in the home.

Proper diet, not smoking, adequate rest and exercise also are important, but hand washing is a big part of the effort to stay healthy this winter and throughout the year.

(Media Contacts)

Last Updated March 19, 2009