Community-based epidemiologic studies have shown that hand sanitizers have beneficial effects. Hand sanitizers have been found to be effective in reducing gastrointestinal illnesses in households (Sandora et al., 2004), in curbing absentee rates in elementary schools (Hammond, Ali, Fendler, Dolan, & Donovan, 2000), and in reducing illnesses in university dormitories (White et al., 2003). An Internet search retrieved recommendations for hand hygiene from schools, daycare centers, outdoor guides, and animal shelters.
To reduce infections in health care settings, alcohol-based hand sanitizers are recommended as a component of hand hygiene (Boyce & Pittet, 2002). For alcohol-based hand sanitizers, the Food and Drug Administration (FDA) recommends a concentration of 60 percent to 95 percent ethanol or isopropanol (FDA, 1994), the concentration range of greatest germicidal efficacy While non-health-care groups also recommend alcohol-based hand sanitizers, they usually do not specify an appropriate concentration of alcohol.
Some products marketed to the public as antimicrobial hand sanitizers are not effective in reducing bacterial counts on hands. In the course of a classroom demonstration of the comparative efficacy of hospital-grade antimicrobial soap and alcohol-based sanitizers, a product with 40 percent ethanol as the active ingredient was purchased at a retail discount store. Despite a claim on the label that the product reduces "germs and harmful bacteria" by 99.9 percent, we observed an apparent increase in the concentration of bacteria in handprints impressed on agar plates after cleansing. Such an effect was not found with any of the other hand cleaners.
Subsequently, we conducted more formal handwashing trials to verify the preliminary finding. Our goal was not to test the products by using the FDA tentative final monograph standard (FDA, 1994), but to determine whether a marketed product fails as an antiseptic because of its low alcohol content. To test whether the relatively low concentration of ethanol was the source of treatment failure, we included trials with laboratory-formulated 40 percent ethanol; we also supplemented the suspect gel with ethanol to a final concentration of 62 percent. Five hand hygiene treatments were compared: tap water (four trials), 40 percent ethanol (five trials), commercial gels with active ingredients of either 40 percent or 62 percent ethanol (nine trials each), and commercial 40 percent gel...