FYI Research:
Study shows soap and water are still the best way to wash

Antibacterial gels, alcohol hand sanitizers, antibacterial wipes. There are so many quick ways to keep your hands clean, it’s hard to choose. But don’t forget to also wash your hands with good old soap and water — it works just as well as antimicrobial products in removing bacteria and still works best against viruses, including those that cause the common cold, according to the largest, most comprehensive study of hand hygiene products to date.

The study, led by Emily E. Sickbert-Bennett, a public health epidemiologist with the UNC Health Care System and the School of Public Health, was designed to test how well various products work to prevent infection in hospitals and other health-care settings. But some of the results can apply to you.

The researchers tested 12 different hand-sanitizing products that contained active ingredients similar to products you can buy at any drug or grocery store. Participants’ hands were infected with bacteria, then the participants washed or sanitized their hands for just 10 seconds. In similar studies, subjects have washed their hands for the recommended time of 30 seconds, but the shorter time is more realistic, especially for busy health-care workers, Sickbert-Bennett said.

After just one contamination with bacteria and one washing, all the products except two worked pretty well against bacteria, removing 90 to 99 percent of the bacteria on hands. The products that did significantly worse were two different kinds of moist anti-microbial towelettes.

Soaps used at the sink with water were most effective against bacteria. In just one washing, it didn’t matter whether the soap contained anti-microbial agents or not — both methods worked about the same.

The effectiveness changed a bit after multiple contaminations and washes, such as might happen with a health-care worker. Under these conditions, the soaps containing anti-microbial agents worked slightly better against bacteria than plain soaps, and the waterless, alcohol-based hand rubs lost some of their effectiveness.

With viruses, which are hard to actually kill with these products, nothing worked better than physically removing them with plain soap and water. The alcohol-based hand rubs were generally ineffective in reducing the amount of virus on the hands.

The study shows that some products were more effective than others, but it doesn’t mean that the less-effective products don’t help at all, Sickbert-Bennett says. “Even the products that didn’t work as well may have removed enough organisms from the hands to prevent illness,” she says.

Still, it looks like your mother was right — don’t forget to wash your hands, and use plenty of soap and water.

Other study authors are William A. Rutala and David J. Weber, professors of medicine and epidemiology at the schools of medicine and public health; Mark D. Sobsey, professor of environmental sciences and engineering in public health; and medical technologist Maria F. Gergen-Teague. Gregory P. Samsa, a Duke University biostatistician, helped analyze the data.

The findings were published in the March 2005 issue of the “American Journal of Infection Control.” The N.C. Statewide Program for Infection Control and Epidemiology supported the research.

Provided by Research and Economic Development.
Editor: Neil Caudle. Writer: Angela Spivey.

Technology transfer update

Technology transfer update

The Office of Technology Development helps Carolina faculty, students and staff develop and commercialize patentable inventions resulting from their research. In February 2005, the University executed no license agreements and had one U.S. patent issued.

A patent is a legal document granting inventors the exclusive right to prevent others from making, using or selling an invention for a number of years. A license agreement is a written contract granting permission for a person or company to use an invention under certain terms. For more information about OTD, go to research.unc.edu/otd.