Hand sanitizer is a common sight these days. Many office workers keep a bottle near their keyboard. Moms carry it in their diaper bags. Teachers put it on their desks. There’s a dispenser for it in every doctor’s office and hospital room. Repeated studies have shown that ethanol-based hand sanitizers are effective at killing viruses, but soap and water is still the best cleanser in some cases.
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Ethanol, also called ethyl alcohol, has been used in hand-sanitizing gels, creams and foams for decades. Most hand sanitizers contain some form of ethanol as well as other chemicals or organic agents and fragrances. Hand santizers help conserve water, kill bacteria faster than washing hands with soap and water, save time and provide a cleansing option when a sink is not readily available.
Preventing the Common Cold
In a 2010 study by the American Society for Microbiology, ethanol-based hand sanitizers were found significantly more effective at eliminating rhinovirus, the virus that causes the common cold, than washing with soap and water. In this study, results were the same whether subjects used a solution containing 65 percent ethanol or 80 percent ethanol. This study also found that hands cleansed with sanitizer remained disinfected for about four hours. Since hand-to-hand transmission is one of the most common ways of spreading viruses, the ASM recommends using ethanol-based hand sanitizers as a way of preventing the spread of the common cold.
In a 2008 study by ASM, ethanol-based hand sanitizers with additives were found to be effective at killing surrogate rotavirus, poliovirus, and norovirus after a 30-second exposure. Other alcohol-based sanitizers, on the other hand, only eliminated human rotavirus. Since norovirus is the leading cause of food-related illness in the United States, ASM recommends ethanol-based sanitizers for use by food handlers to reduce the transmission of these viruses. Ethanol alone can rapidly kill vegetative bacteria -- such as Bacillus and Clostridium, fungi and enveloped viruses. ASM researchers used a sanitizer with 70 percent ethanol as the active ingredient.
According to the Centers for Disease Control and Prevention, ethanol-based hand antiseptics containing 60 to 90 percent ethanol appear to be most effective against common pathogens. Ethanol-based sanitizers also seem to have greater antimicrobial effects against viruses than isopropanol-based sanitizers.
The CDC still recommends washing hands with soap and water for the best cleansing. If your hands are visibly dirty or contaminated with organic material, they must be washed with soap and water. Sanitizers might kill germs, but they can’t remove dirt or grime like soap and water can. Also, it’s important to note that, when using hand sanitizer, you must use enough to cover all surfaces of the hands and fingers to achieve effective disinfection. Always make sure that you use hand sanitizer with at least 60 percent ethanol as the active ingredient. The average hand sanitizer contains about 62 percent ethanol.
- American Society for Microbiology: Effectiveness of Hand Sanitizers with and without Organic Acids for Removal of Rhinovirus from Hands
- American Society for Microbiology: Improved Inactivation of Nonenveloped Enteric Viruses and Their Surrogates by a Novel Alcohol-Based Hand Sanitizer
- Centers for Disease Control and Prevention: General information on Hand Hygiene