The Medical Minute: Hand-washing is defensive medicine

December 15, 2004

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

Catching a cold

December brings winter weather, arctic winds, holiday melodies in the air, and the sound of coughing and sneezing all around us. Although many individuals think colds are contracted from the germs they breathe, the truth is, cold viruses are caught literally in people's hands. Once on the hands, people infect themselves.

Cold viruses are four times more likely to be on the hands of someone with a cold than in their sneezes. Environmental surfaces such as counters, cups and doorknobs allow viruses to live for hours. When someone shakes hands with infected people or touch things they have touched, they may pick up the viruses. By touching noses or eyes, people put the virus into their own systems, where it can lead to infection. Kissing or sipping from someone else's cup actually is less likely to spread a cold than simply touching one's nose, since it takes 8,000 times fewer viruses to infect noses than mouths.

Hand-washing has been shown to significantly reduce 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.

Gut feelings

Intestinal diseases from simple diarrhea to hepatitis A are reduced when food preparers wash their hands. The Centers for Disease Control (CDC) 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.

Lather up

To be effective, hands should be rubbed together vigorously with soap and warm water for at least 15 seconds. Brief rubbing or simply rinsing under running water is not enough. Contaminants are stuck in oils that adhere to the skin. Agitation by rubbing loosens the dead skin cells and soap keeps the contaminants and germs suspended in the water so they rinse off. Soap does not kill the bacteria. In fact, germicidal soaps must remain in contact with the skin for several minutes to kill germs. Anti-bacterial soaps may give a false sense of security that could lead to less-vigorous washing.

Health-care workers should lead the way

Medical personnel are exposed to bacteria and viruses that are more dangerous than those most non-medical people experience. Unfortunately, studies have demonstrated inconsistent adherence to hand-washing practice by doctors in hospital settings. Complaints about too few sinks or dry and cracked skin have contributed to inconsistent washing of hands.

New rules have been introduced to emphasize the importance of clean hands and new hand sanitizers are being used to help with the effort. These 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. With their introduction, non-medical people also may benefit. 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 still should be removed by washing, but hand sanitizers can eliminate germs that cause colds and other illnesses.

Save a germ

All germs are not bad. Some scientists believe that our immune systems learn to distinguish bad germs from good germs by being exposed to dirt and germs early in life. Studies are ongoing, but many doctors think that excessively clean environments may not be a good idea. It may not be necessary to maintain a completely antiseptic environment for children, but teaching children to wash their hands before eating and after using the bathroom is important.

Don't shake on it

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 CDC is suggesting we cough or sneeze into the crux of our elbow to keep viruses off our hands. We can reduce our own risk of illness by learning not to touch our eyes or noses until after we have washed our hands thoroughly or used one of the new skin sanitizers. Extra care will continue to be the rule for medical personnel and food handlers.

Keep healthy this winter and through the year. Cleanliness may or may not be next to godliness, but clean hands certainly lead to good health. More details on the importance of hand washing is available at the CDC at and the American Society for Microbiology at

(Media Contacts)

Last Updated March 19, 2009