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Study: Soap and water work best in ridding hands of
viruses
Posted March 22, 2005
Courtesy University of North Carolina at Chapel Hill
and World Science staff
The largest study ever done comparing the effectiveness of hand hygiene products shows that nothing works better than simply washing hands with good old-fashioned soap and water, researchers say.
Among the viruses that soapy hand washing flushes down the drain is the one that causes the common cold. Other removable viruses cause hepatitis A, acute gastroenteritis and a host of other illnesses.
A separate finding was that waterless handwipes only removed roughly 50 percent of bacteria from volunteers’ hands.
“We studied the efficacy of 14 different hand hygiene agents in reducing bacteria and viruses from the hands,” said Emily E. Sickbert-Bennett, an epidemiologist with the University of North Carolina Health Care System. “No other studies have measured the effectiveness in removing both bacteria and viruses at the same time.”
For the first time, too, the researchers tested what happened when people cleaned their hands for only 10 seconds, Sickbert-Bennett said. That
was the average length of time researchers observed health-care personnel washing or disinfecting their hands at work.
“Previous studies have had people clean their hands for 30 seconds or so, but that’s not what health-care workers usually do in practice, and we wanted to test the products under realistic conditions,” she said.
Anti-microbial agents were best at reducing bacteria on hands, but waterless, alcohol-based agents had variable and sometimes poor effects, becoming less effective after multiple washes, Sickbert-Bennett said. For removing viruses from the hands, physical removal with soap and water was
best.
A report on the findings appears in the March issue of the
American Journal of Infection Control.
“These findings are important because health-care associated infections rank in the top five causes of death, with an estimated 90,000 deaths each year in the United States,” said William A. Rutala of the University of North Carolina, a coauthor of the study. “Hand hygiene agents have been shown to reduce the incidence of health-care associated infections, and a variety of hand hygiene agents are now available with different active ingredients and application methods.
“Our study showed that the anti-microbial hand washing agents were significantly more effective in reducing bacteria than the alcohol-based handrubs and waterless handwipes,” he said. “Our study also showed that, at a short exposure time of 10 seconds, all agents with the exception of handwipes demonstrated a 90 percent reduction of bacteria on the hands.”
Alcohol-based handrubs were generally ineffective in demonstrating a significant reduction of a
hardy virus, Rutala said. While the use of alcohol-based handrubs will continue to be an important infection control measure,
the researchers added, it is important to recommend or require traditional hand washing with soap and water throughout each day.
In the study, the researchers contaminated 62 volunteers' hands with relatively harmless microbes, then had them clean their hands with various methods, and recorded the outcome.
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Front image courtesy U.S. Food
and Drug Administration
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