There is no single means of cleaning hands which is a "magic bullet." Efficacy varies depending upon the pathogen and user technique and the sanitizing agent used.
See the references which correspond to the following findings:
1) Compared to rubbing with an antibacterial liquid with a water rinse only, an alcohol-based hand sanitizer was relatively ineffective against norovirus.
2) 62% alcohol foams were only somewhat more effective than water against E. coli, because the time required for dryness often exceeds the recommended 30 seconds resulted in a small amount being used.
3) Alcohol based hand sanitizer was significantly better than soap and water with respect to reduction in levels of fecal streptococci.
4) An alcohol-based hand sanitizer with polyquaternium polymer and organic acid was superior to alcohol sanitzer against enteric viruses.
5) Antimicrobial handwashing agents were the most efficacious in bacterial removal, whereas waterless agents showed variable efficacy. Alcohol-based handrubs compared with other products demonstrated better efficacy after a single episode of hand hygiene than after 10 episodes. Effective hand hygiene for high levels of viral contamination with a nonenveloped virus was best achieved by physical removal with a nonantimicrobial soap or tap water alone.
1) Appl Environ Microbiol. 2010 Jan;76(2):394-9. Epub 2009 Nov 20.
Effectiveness of liquid soap and hand sanitizer against Norwalk virus on contaminated hands.
Liu P, Yuen Y, Hsiao HM, Jaykus LA, Moe C
Center for Global Safe Water, Hubert Department of Global Health, Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, GA 30322
Disinfection is an essential measure for interrupting human norovirus (HuNoV) transmission, but it is difficult to evaluate the efficacy of disinfectants due to the absence of a practicable cell culture system for these viruses. The purpose of this study was to screen sodium hypochlorite and ethanol for efficacy against Norwalk virus (NV) and expand the studies to evaluate the efficacy of antibacterial liquid soap and alcohol-based hand sanitizer for the inactivation of NV on human finger pads. Samples were tested by real-time reverse transcription-quantitative PCR (RT-qPCR) both with and without a prior RNase treatment. In suspension assay, sodium hypochlorite concentrations of >or=160 ppm effectively eliminated RT-qPCR detection signal, while ethanol, regardless of concentration, was relatively ineffective, giving at most a 0.5 log(10) reduction in genomic copies of NV cDNA. Using the American Society for Testing and Materials (ASTM) standard finger pad method and a modification thereof (with rubbing), we observed the greatest reduction in genomic copies of NV cDNA with the antibacterial liquid soap treatment (0.67 to 1.20 log(10) reduction) and water rinse only (0.58 to 1.58 log(10) reduction). The alcohol-based hand sanitizer was relatively ineffective, reducing the genomic copies of NV cDNA by only 0.14 to 0.34 log(10) compared to baseline. Although the concentrations of genomic copies of NV cDNA were consistently lower on finger pad eluates pretreated with RNase compared to those without prior RNase treatment, these differences were not statistically significant. Despite the promise of alcohol-based sanitizers for the control of pathogen transmission, they may be relatively ineffective against the HuNoV, reinforcing the need to develop and evaluate new products against this important group of viruses.
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2) BMC Infect Dis. 2010 Mar 26;10:78.
Efficacy of ethanol-based hand foams using clinically relevant amounts: a cross-over controlled study among healthy volunteers.
Kampf G, Marschall S, Eggerstedt S, Ostermeyer C.
BODE Chemie GmbH, Scientific Affairs, Melanchthonstr, 27, 22525 Hamburg, Germany. email@example.com
BACKGROUND: Foams containing 62% ethanol are used for hand decontamination in many countries. A long drying time may reduce the compliance of healthcare workers in applying the recommended amount of foam. Therefore, we have investigated the correlation between the applied amount and drying time, and the bactericidal efficacy of ethanol foams.
METHODS: In a first part of tests, four foams (Alcare plus, Avagard Foam, Bode test foam, Purell Instant Hand Sanitizer) containing 62% ethanol, which is commonly used in U.S. hospitals, were applied to 14 volunteers in a total of seven variations, to measure drying times. In a second part of tests, the efficacy of the established amount of foam for a 30 s application time of two foams (Alcare plus, Purell Instant Hand Sanitizer) and water was compared to the EN 1500 standard of 2 x 3 mL applications of 2-propanol 60% (v/v), on hands artificially contaminated with Escherichia coli. Each application used a cross-over design against the reference alcohol with 15 volunteers.
RESULTS: The mean weight of the applied foam varied between 1.78 and 3.09 g, and the mean duration to dryness was between 37 s and 103 s. The correlation between the amount of foam applied and time until hands felt dry was highly significant (p < 0.001; Pearson's correlation coefficient: 0.724; 95% confidence interval: 0.52-0.93). By linear correlation, 1.6 g gave an intercept of a 30 s application time. Application of 1.6 g of Purell Instant Hand Sanitizer (mean log10-reduction: 3.05 +/- 0.45) and Alcare plus (3.58 +/- 0.71) was significantly less effective than the reference disinfection (4.83 +/- 0.89 and 4.60 +/- 0.59, respectively; p < 0.001). Application of 1.6 g of water gave a mean log10-reduction of 2.39 +/- 0.57.
CONCLUSIONS: When using 62% ethanol foams, the time required for dryness often exceeds the recommended 30 s. Therefore, only a small volume is likely to be applied in clinical practice. Small amounts, however, failed to meet the efficacy requirements of EN 1500 and were only somewhat more effective than water.
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3) Am J Trop Med Hyg. 2010 Feb;82(2):270-8.
Efficacy of waterless hand hygiene compared with handwashing with soap: a field study in Dar es Salaam, Tanzania
Pickering AJ, Boehm AB, Mwanjali M, Davis J
Emmett Interdisciplinary Program in Environment and Resources, School of Earth Sciences and Civil and Environmental Engineering, and Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA. firstname.lastname@example.org
Effective handwashing with soap requires reliable access to water supplies. However, more than three billion persons do not have household-level access to piped water. This research addresses the challenge of improving hand hygiene within water-constrained environments. The antimicrobial efficacy of alcohol-based hand sanitizer, a waterless hand hygiene product, was evaluated and compared with handwashing with soap and water in field conditions in Dar es Salaam, Tanzania. Hand sanitizer use by mothers resulted in 0.66 and 0.64 log reductions per hand of Escherichia coli and fecal streptococci, respectively. In comparison, handwashing with soap resulted in 0.50 and 0.25 log reductions per hand of E. coli and fecal streptococci, respectively. Hand sanitizer was significantly better than handwashing with respect to reduction in levels of fecal streptococci (P = 0.01). The feasibility and health impacts of promoting hand sanitizer as an alternative hand hygiene option for water-constrained environments should be assessed.
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4) Appl Environ Microbiol. 2008 Aug;74(16):5047-52. Epub 2008 Jun 27.
Improved inactivation of nonenveloped enteric viruses and their surrogates by a novel alcohol-based hand sanitizer.
Macinga DR, Sattar SA, Jaykus LA, Arbogast JW
GOJO Industries, Inc., One GOJO Plaza, Suite 500, Akron, OH 44311 email@example.com
Norovirus is the leading cause of food-related illness in the United States, and contamination of ready-to-eat items by food handlers poses a high risk for disease. This study reports the in vitro (suspension test) and in vivo (fingerpad protocol) assessments of a new ethanol-based hand sanitizer containing a synergistic blend of polyquaternium polymer and organic acid, which is active against viruses of public health importance, including norovirus. When tested in suspension, the test product reduced the infectivity of the nonenveloped viruses human rotavirus (HRV), poliovirus type 1 (PV-1), and the human norovirus (HNV) surrogates feline calicivirus (FCV) F-9 and murine norovirus type 1 (MNV-1) by greater than 3 log(10) after a 30-s exposure. In contrast, a benchmark alcohol-based hand sanitizer reduced only HRV by greater than 3 log(10) and none of the additional viruses by greater than 1.2 log(10) after the same exposure. In fingerpad experiments, the test product produced a 2.48 log(10) reduction of MNV-1 after a 30-s exposure, whereas a 75% ethanol control produced a 0.91 log(10) reduction. Additionally, the test product reduced the infectivity titers of adenovirus type 5 (ADV-5) and HRV by > or =3.16 log(10) and > or =4.32 log(10), respectively, by the fingerpad assay within 15 s; and PV-1 was reduced by 2.98 log(10) in 30 s by the same method. Based on these results, we conclude that this new ethanol-based hand sanitizer is a promising option for reducing the transmission of enteric viruses, including norovirus, by food handlers and care providers.
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5) Am J Infect Control. 2005 Mar;33(2):67-77
Comparative efficacy of hand hygiene agents in the reduction of bacteria and viruses.
Sickbert-Bennett EE, Weber DJ, Gergen-Teague MF, Sobsey MD, Samsa GP, Rutala WA.
Department of Hospital Epidemiology, University of North Carolina Health Care System, North Carolina, USA. firstname.lastname@example.org
BACKGROUND: Health care-associated infections most commonly result from person-to-person transmission via the hands of health care workers.
METHODS: We studied the efficacy of hand hygiene agents (n = 14) following 10-second applications to reduce the level of challenge organisms (Serratia marcescens and MS2 bacteriophage) from the hands of healthy volunteers using the ASTM-E-1174-94 test method.
RESULTS: The highest log 10 reductions of S marcescens were achieved with agents containing chlorhexidine gluconate (CHG), triclosan, benzethonium chloride, and the controls, tap water alone and nonantimicrobial soap and water (episode 1 of hand hygiene, 1.60-2.01; episode 10, 1.60-3.63). Handwipes but not alcohol-based handrubs were significantly inferior from these agents after a single episode of hand hygiene, but both groups were significantly inferior after 10 episodes. After a single episode of hand hygiene, alcohol/silver iodide, CHG, triclosan, and benzethonium chloride were similar to the controls in reduction of MS2, but, in general, handwipes and alcohol-based handrubs showed significantly lower efficacy. After 10 episodes, only benzethonium chloride (1.33) performed as well as the controls (1.59-1.89) in the reduction of MS2.
CONCLUSIONS: Antimicrobial handwashing agents were the most efficacious in bacterial removal, whereas waterless agents showed variable efficacy. Alcohol-based handrubs compared with other products demonstrated better efficacy after a single episode of hand hygiene than after 10 episodes. Effective hand hygiene for high levels of viral contamination with a nonenveloped virus was best achieved by physical removal with a nonantimicrobial soap or tap water alone.
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Also see comments on this paper in:
Am J Infect Control. 2005 Sep;33(7):431-4; author reply 436-7.
Am J Infect Control. 2005 Sep;33(7):435-6; author reply 436-7.
Am J Infect Control. 2005 Nov;33(9):558-60.
Am J Infect Control. 2005 Sep;33(7):429-31; author reply 436-7.