EAST LONGMEADOW, MASS.—After an exhaustive two-year process, a University of Arizona Health Sciences research team has announced the publication of their work, Comparison of electric hand dryers and paper towels for hand hygiene: a critical review of the literature. The review culled the current breadth of data, including published studies, news reports and online content, seeking to uncover which hand drying method, hand dryers or paper towels, is more hygienic and safer relative to human health risks. The researchers found that, while studies in the public arena generally favor paper towels over hand dryers, the conclusions are largely misleading and unsubstantiated.
Through the scientific research, the use of hand dryers and paper towels to dry hands were found to be equal from a health and safety perspective; the findings echo recommendations from the World Health Organization that everyone “frequently clean [their] hands…” and “dry [them] thoroughly by using paper towels or a warm air dryer,” and the Centers for Disease Control and Prevention that report that, “Both [clean towels or air hand dryers] are effective ways to dry hands.”
To conduct the study, the research team considered 293 papers and published studies for inclusion in their review, rejecting 270 for failing to meet review criteria or for reporting generalized recommendations without sufficient scientific evidence. The 23 peer-reviewed studies that met the inclusion criteria were categorized and prioritized based on their scientific rigor, a score determined by taking into account such factors as sample size, methodology, data quality and whether or not the study was set up to represent real-world scenarios.
The study that was found to have the highest rigor score was an independent study conducted by the Mayo Clinic, Effects of 4 Hand-Drying Methods for Removing Bacteria From Washed Hands: A Randomized Trial. It found that “…there is no difference in bacteria counts when drying with paper towels or hand dryers.” Only three studies received positive rigor scores for having realistic testing conditions, and none of the studies reported any negative effects of either hand drying method on human health.
No Study Has Examined Best Drying Method
Although numerous studies have been published evaluating the “best” method for hand drying, “best” has been defined in a variety of ways relative to bacterial removal efficacy, environmental contamination potentials, ecological or cost benefits, noise and more. Kelly Reynolds, MSPH, Ph.D., the corresponding author of the review explained that, “No study to date has examined the “best” drying method,” and that she and her team, “found no empirical data to support one hand drying method over another from a health and safety perspective.”
In light of the coronavirus pandemic, hand hygiene has been widely covered in the media. Reynolds shared that, “Media reports frequently used sensationalized headlines. While such headlines may increase traffic, they sometimes overgeneralize or exaggerate research results. Consumers may only read the headlines which can influence public opinion toward biased or erroneous conclusions.”
“At a time when proper hand washing and drying is of the utmost importance, exclusively recommending paper towels is limiting, and frankly, irresponsible,” said William Gagnon, Vice President of Marketing and Sales at Excel Dryer. “Hand dryers provide an effective way to achieve completely dry hands, a critical part of proper hand hygiene, the top defense against the spread of germs, like coronavirus.”
The scoping review’s conclusion calls for future studies to examine the relationship between contamination that occurs due to hand-drying methods and human health outcomes. They offer that this can be accomplished by utilizing real-world scenarios while controlling certain variables.