by Brianna Crandall — July 10, 2020 — In the ongoing quest to reduce the spread of illness-causing pathogens, particularly today’s need to fight the SARS-CoV-2 coronavirus that causes COVID-19, should you rely on paper towels or hand dryers in your commercial restrooms? A long-time debate between the two schools of thought (including sustainability and janitorial considerations) has been fueled by both misinformation and a lack of definitive research results, but one thing that both sides seem to agree on is that proper hand hygiene — including both washing and drying hands thoroughly — is a top defense against the spread of germs, including the virus that causes COVID-19.
FMLink looked into the current research and advice from health authorities to help facilities managers (FMs) get a clearer picture of the issue.
According to the US Centers for Disease Control and Prevention (CDC) page Show Me the Science — How to Wash Your Hands:
The best way to dry hands remains unclear because few studies about hand drying exist, and the results of these studies conflict. Additionally, most of these studies compare overall concentrations of microbes, not just disease-causing germs, on hands following different hand-drying methods. It has not been shown that removing microbes from hands is linked to better health. Nonetheless, studies suggest that using a clean towel or air-drying hands are best.
The World Health Organization (WHO) Mythbusters page notes that hand dryers (or, it is implied, paper towels) on their own will not kill the virus:
To protect yourself, frequently clean your hands with an alcohol-based hand rub or wash them with soap and water. Once your hands are cleaned, you should dry them thoroughly by using paper towels or a warm air dryer.
In order to evaluate the applicability of results from a test, it is important to differentiate between various forms of pathogens. Each virus and bacterium is different and spreads differently. So unless a test were carried out on a specific one, we don’t know for sure which method is better for that pathogen. Also, many of the tests have been designed with concentrations of illness-causing pathogens that are not realistic, given that most (if not all) of these germs will have been removed through proper handwashing.
Here is what we do know:
- Frequent, proper hand washing (20 seconds with soap) is the most effective way to remove germs from one’s hands. It is best to use a touchless faucet or find a way to turn the faucet off without touching it when done.
- Germs of any kind are more likely to spread from wet hands rather than dry ones (as demonstrated in a bacterial transfer study in New Zealand listed in the National Institutes of Health [NIH] database), so it is important to dry one’s hands thoroughly, preferably without touching either other soiled paper towels, the dispenser, or the air dryer.
The following are considerations related to paper towels:
- Paper towels appear to cause little or no airborne contamination of clothes or surrounding surfaces in a restroom (as shown in a British study in which contaminated gloved hands were not properly washed before drying).
- A 2011 study in the American Journal of Infection Control demonstrated that a large community of culturable bacteria, including toxin producers, can be isolated from unused paper towels and that they may be transferred to individuals while drying hands, although there was no evidence of bacterial airborne transmission while drying.
- When towels get jammed or don’t feed through the dispenser properly, people may touch the dispenser to try to unjam the towels, which can deposit germs on the dispenser from improperly washed hands.
- Damp towels in a trash can become a central place for any pathogens to reside. If the can is not covered, the germs can get back into the air; if it is covered, people may need to touch it to get the paper towels through the opening.
The following are considerations related to hand dryers:
- Hand dryers with HEPA filters will filter out most contaminants coming from the hand dryer’s airstream.
- Hand dryers don’t create germ-carrying waste.
- Hand dryers with buttons do require physical contact for use, increasing the risk of spreading germs.
- Hand dryers can blow germs from improperly washed hands into the air (as shown in the British study listed above, in which contaminated gloved hands were not properly washed).
However, although airborne contamination by hand dryers has been demonstrated for unwashed hands, there is no evidence that this is true for the virus causing COVID-19.
As a rebuttal to recent speculations that hand dryers may be contributing specifically to the spread of the coronavirus, leaders from Excel Dryer, manufacturer of XLERATOR Hand Dryers (see Excel’s FMLink page specifically for FMs), quoted these health authorities in support of the use of air dryers:
- CDC (March 2020): “We have no evidence that hand dryers are spreading the coronavirus…”
- Dr. Larry Chang, Johns Hopkins Medicine (March 2020): “Are hand dryers spreading the coronavirus? Our experts said no. There is no evidence that these hand dryers are spreading the virus.”
- Kelly Reynolds, Ph.D., Professor and Department Chair at the Mel & Enid Zuckerman College of Public Health at the University of Arizona: “…the breadth of data available does not favor one hand drying method as being more hygienic or safer.”
In a hand-drying study listed in the National Center for Biotechnology Information database at NIH, results showed that hands dried with a jet air dryer harbored fewer viable bacteria than when dried with a paper towel, reducing the risk of infection transmission via touch (especially important for healthcare workers). However, this implies that the bacteria must have gone somewhere else, which could have been into the air. So it is unclear which drying method comes out on top. Again, the reader is cautioned that this test was with non-typical concentrations and the bacteria was different than the current pandemic virus.
Another NIH-listed hand-drying trial conducted by Mayo Clinic demonstrated no statistically significant differences in the efficiency of four different hand-drying methods for removing bacteria from washed hands: cloth towels accessed by a rotary dispenser, paper towels from a stack on the hand-washing sink, warm forced air from a mechanical hand-activated dryer, and spontaneous room air evaporation.
A 2005 NIH-listed test with paper towels and hand dryers in Japan concluded that holding hands stationary (under warm air) and not rubbing them was desirable for removing bacteria. Ultraviolet light reinforced the removal of bacteria during warm air drying. [Note: WHO says UV radiation should not be used to disinfect hands or skin, as it can cause skin irritation and damage eyes.] Paper towels were shown to be useful for removing bacteria from fingertips but not palms and fingers.
Thus, hand dryers and paper towels each have their own strengths and weaknesses. What both sides agree on is that the most important way to help reduce the spread of COVID-19 and related illnesses is:
- Wash thoroughly, and
- Dry thoroughly.