High-powered hand dryers, like the ones used in public restrooms, are the latest pawns in the relentless pursuit to repulse individuals fixated on cleanliness

For decades, microbiologists have regularly fanned out in hospitals and swabbed the hands of doctors, nurses, and staff, to demonstrate how often infectious agents get passed on to patients through interactions with their caregivers (due to lack of proper handwashing procedures prior to entering a patient’s hospital room, for example). One thing that was a regular on these fishing expeditions was to swab the ties worn by physicians and report on the interesting and disturbing array of infectious agents that were found.

Well, the microbiologists are at it again! After studying hand drying techniques, researchers at The University of Westminster in London determined that high-powered jet air dryers can act like “virus hand grenades.”

Jet Air Dryers versus Warm Air Dryers versus Paper Towels

The study, published in the Journal of Applied Microbiology earlier this year, compared the virus-spreading capabilities of three different types of hand-drying techniques: warm air dryers, jet air dryers, and paper towels.

To perform the research, participants placed MS2, a harmless virus, on their gloved hands. They then dried their hands using the various drying methods. Researchers collected samples from around the three devices and placed them in petri dishes. They took the samples from different heights and distances, and from the air, to rate the ability of the three hand-drying methods to scatter contaminants into the surrounding environment.

The scientists discovered that jet air dryers have the ability to disperse viruses up to nine feet from the device. By contrast, the more commonly used and less powerful warm air dryer could only spew the MS2 three feet from the machine. The paper towels were only able to disperse the virus a mere 10 inches.

Dyson Takes Issue with Study

The hand dryer used for the study was the Dyson Airblade. The researchers determined that the high-powered Airblade spread 60 times more germs into the air than lower-powered warm air dryers, and scattered 1300 more viruses than paper towels.

According to an article in Popular Science, Dyson criticized a previous study in 2014, noting that the scientists, which were the same researchers that conducted this most recent study, had an unusually high amount of the virus on their hands. The company also stated that, while paper towels may not dispense viruses into the air, they can be polluted with germs from other people. In addition, Dyson claims on their website that “up to 88% of unused paper towels tested in the U.S. contain bacteria, which can transfer to your hands.”

The Popular Science article also noted that, in the past, Dyson has alleged that such studies are funded by the paper towel industry to discredit the effectiveness of their products.

In addition to having a large amount of the virus on their hands, it is worth noting that the researchers did not attempt to wash the MS2 from their hands before using the assorted drying techniques. People typically wash their hands with soap and water before operating any type of hand dryer or wiping their hands with paper towels.

Hand Hygiene Critical to Disease Prevention

Nevertheless, although it is debatable which hand-drying method is the most hygienic, the cleanest practice is to thoroughly wash hands and dry them with whatever hand-dryer is available.

Hand hygiene is widely known to be a crucial element in minimizing the transmission of pathogenic micro-organisms that can cause infections. According to the study “it has been estimated that cross-infection contributes to 40% of cases of healthcare-associated infections, and hand hygiene compliance represents an essential step in minimizing such infections.”

Christopher E. Mason, PhD (above), is Professor of Genetics & Computational Biology, Weill Cornell Medical College. Dr. Mason is seen here collecting samples from a New York City subway turnstile as part of the Metagenomics and Metadesign of the Subways and Urban Biomes (MetaSUB) research project. The MetaSUB International Consortium is made up of experts across many fields including genomics, data analysis, engineering, public health, and design, all working together to bring a molecular view of cities to improve their design, use, and impact on health. (Photo/caption copyright: The Wall Street Journal/Weill Cornell Medical College.)

Christopher E. Mason, PhD (above), is Professor of Genetics & Computational Biology, Weill Cornell Medical College. Dr. Mason is seen here collecting samples from a New York City subway turnstile as part of the Metagenomics and Metadesign of the Subways and Urban Biomes (MetaSUB) research project. The MetaSUB International Consortium is made up of experts across many fields including genomics, data analysis, engineering, public health, and design, all working together to bring a molecular view of cities to improve their design, use, and impact on health. (Photo/caption copyright: The Wall Street Journal/Weill Cornell Medical College.)

The research scientists stated that the significance of this study is that “the choice of hand-drying device should be considered carefully in areas where infection prevention concerns are paramount, such as healthcare settings and the food industry.”

Other Studies Examined Subway Turnstiles and Doctors’ Neckties

In the past, microbiologists have performed studies where they swabbed the hands of medical staff, equipment, and surfaces, to demonstrate the presence of infectious agents. Some studies have even examined doctors’ neckties and found the existence of bacteria that can cause infections, such as:

Klebsiella pneumoniae;

Pseudomonas aeruginosa;

Staphylococcus aureus; and

Aspergillus, (a fungus).

In 2013, Weill Cornell Medical College launched a project called PathoMap to study genetic material in the New York City subway system. The objective of the research was to establish a molecular view of the city, and to positively impact public health.

Researchers discovered genetic material from more than 15,000 species in the more than 1400 samples collected from 468 subway stations. Thankfully, most of the material was harmless or unidentified.

PathoMap has recently started an international consortium titled MetaSUB (Metagenomics and Metadesign of Subways and Urban Biomes) to perform similar studies of mass-transit systems in 39 cities on six continents. The goal is to help city planners, public health officials, and designers create healthier environments.

Whether “virus hand grenades” are a fact or a myth, targeted research like the studies above can reveal new ways to improve hygiene, lower the rate of infections, and protect the health of patients.

Meanwhile, research studies like these demonstrate how microbiologists are motivated to go above and beyond the expected in their efforts to help make the world a healthier and safer place for all of us. From that perspective, they uphold the finest traditions of medical laboratory medicine.

—JP Schlingman

Related Information:

Study: ‘Jet’ Hand Dryers Act Like Virus Hand Grenades

Hand Dryer vs. Paper Towel: Which is Cleaner?

Dyson Hand Dryers Spread More Germs Than Paper Towels, Study Says

Do Jet Hand Dryers Really Spread More Germs Than Paper Towels?

Evaluation of the Potential for Virus Dispersal During Hand Drying: A Comparison of Three Methods

Study Finds Doctors’ Neckties Carry Pathogens

There Are 15,000 Lifeforms Riding the NYC Subway, Including Meningitis

Up to 88% of Unused Paper Towels Tested in the U.S. Contain Bacteria, Which Can Transfer to Your Hands

Other Hand Dryers Can Blow Viruses and Bacteria onto Your Hands, Some of It from Feces

Microbiologists at Weill Cornell Use Next-Generation Gene Sequencing to Map the Microbiome of New York City Subways