Purpose: Meta-analyses contrast and combine results from different studies to identify patterns, sources of disagreement, or other interesting relationships that may come to light in the context of multiple studies. This study was undertaken in an effort to determine those factors contributing to hand sanitizer effectiveness.
Methods: A search of hand sanitizer literature was conducted, and included searching for published data on the effects of hand sanitizers on bacteria and viruses. Data on sample size, experiment protocol used, sanitizing agent, concentration of antimicrobial, exposure time, exposure volume, organism, mean starting microbial concentration, and log reduction were recorded and a database was complied. Histograms, linear regression analysis, ANOVA, and post hoc Tukey’s range test were all used to analyze the data.
Results: Twenty-eight publications, containing 336 observations, met the criteria for the study. There was a significant difference (P < 0.001) between ethanol (EtOH) and isopropanol (IsoP) effectiveness. IsoP had a higher mean log reduction (4.2 log CFU) than EtOH (3.7) for bacterial data sets, but not for virus datasets. Significant differences were seen between testing protocols. Log reductions, as measured by fingerpad and glove juice methods (both 1.5 mean log reduction), were significantly lower than those based on European Standard EN 1500 methods (3.5 mean log reduction). Alcohol-based hand sanitizers (3.8 mean log reduction) were more effective (P < 0.005) than those based on other antimicrobials (2.6 mean log reduction).
Significance: The choice of a testing protocol has a great influence on measured hand sanitizer effectiveness. Alcohol-based hand sanitizers are more effective than those based on other antimicrobials for both bacteria and viruses.