Hand hygiene has always been important. Unclean hands are responsible for 80 percent of respiratory tract infections such as cold, flu, diarrhea and intestinal illnesses, common eye infections, which can be caused by bacteria and germs that get into your eyes from your hands. Dirty hands can also lead to breakouts, blackheads, etc., and can cause redness and rashes in people with sensitive skin.

However, more and more people are becoming aware of hand hygiene since the COVID-19 pandemic began. This year, the WHO theme, “Hand Hygiene for All” caught global attention as it highlighted the elevated importance of handwashing during the COVID-19 pandemic as a method to prevent the rise and spread of the virus. There are many benefits of handwashing for the health of an individual. 

Firstly, hand hygiene is the single best method to prevent infection. Hand hygiene means cleaning your hands by using soap and water or an alcohol-based hand sanitizer for a minimum of 20 seconds. Cleaning your hands will prevent germs transmission, particularly antibiotic-resistant bacteria that are becoming more difficult to handle. On average, healthcare workers spend only half the required number of times to clean their hands. According to the Centres for Disease Control and Prevention (CDC), using an alcohol-based hand sanitizer is the best way to clean our hands. Alcohol-based hand rubs are more sufficient in decreasing the number of germs in the hands.

Although hand sanitizers are the best way to clean the hands, there are some situations in which soap and water should be considered. For instance, if the hands are visibly soiled, before eating, and after using the toilet.

However, there is another very important step to hand hygiene, one that is seldom talked about - hand drying. “Effective hand hygiene is not only about thorough hand washing but needs to include drying hands properly. Hand washing is a crucial way of reducing the spread of bacteria and viruses, but drying hands properly is also an important step as it prevents the transference of them to and from hands. In fact, we know that damp hands can transfer up to 1,000 times more bacteria than dry hands (Patrick D, Findon G, and Miller T, 1997),” says Salomé Giao, Senior Scientist at Dyson.

Pathogens can persist for several hours on hands, and residual hand moisture is associated with increased microorganism transfer from hands to surfaces. Thus, as much as handwashing is important, the process of hand drying is equally essential in minimizing the risk of pathogen spread.

The most effective hand drying method

The proper drying of hands should be an essential component of effective hand hygiene procedures. Drying your hands properly is just as important since wet or moist hands can breed germs. 

“The hygienic efficacy of hand drying includes drying efficiency, the effective removal of bacteria, and the prevention of cross-contamination. Different drying methods have different levels of effectiveness, with paper towels being one of the best and air dryers being the worst. Drying hands thoroughly with single-use, disposable paper towels is the preferred method of hand drying in terms of hand hygiene,” says Jibi Thankachan, Specialist & Preventionist - Infection Control Admin at King Saud Medical City & Covid Rapid Response at Central First Health Cluster, Riyadh. 

This conclusion raises the question of what types of paper towels should be used for hand drying. Does the quality of paper towels have an effect on hand hygiene adherence? When recycled paper is used for hand drying, what kinds of studies are appropriate to assess the cost-benefit of using recycled paper? Many questions remain unanswered. Jibi continues, “Different types of paper towels may have different absorption characteristics, which can influence their capacity to remove bacteria from washed hands. The quality of the paper towels is important because poor-quality towels can damage the skin by abrasion and ineffective drying. Recycled paper would be more acceptable in the future because it can contribute to environmental sustainability. Such research may have the potential to improve hand hygiene practice and sustainable development significantly.” 

Jibi further says that the use of high-speed hand dryers can transfer germs to a person's clothing and lead to an increase in spreading those contaminants to other surfaces. Warm air or jet air dryers, on the other hand, don't come much recommended. They can spew germs back on your hands, and into the air where you can breathe them in. “Research studies show that drying with paper towels or cloth towels removes even more germs than washing alone, as the friction of drying reduces the germ count even further."

 Indeed, one study found that air dryers can blow around potentially pathogenic air. Plus, if you're impatient and don't wait for your hands to dry completely, you'll again have created an environment in which germs can flourish. “I strongly recommended using paper towels when available in public restrooms and keeping a few clean tissues in your pocket for the times they're unavailable,” he concludes. 

Marwa Al-Saad, an Infection Control Educator, and Abdullah Al Asmary, an Environmental Infection Preventionist from Saudi Arabia support this argument. 

“Wet skin is more likely to transmit bacteria than dry skin. Therefore, good hand drying following hand washing should be considered. The debate regarding the hygienic effectiveness of different hand-drying methods is still ongoing. According to the World Health Organization (WHO), hands washed with soap and water, preferably, should be dried by using a single-use towel or tissue, to prevent recontamination of the hands. In 2012, Cunrui Huang and colleagues did a systemic review analysis regarding the hygienic efficacy of different hand-drying methods from the degree of dryness, the speed of drying, effective removal of bacteria, and prevention of cross-contamination point of view. They found that the majority of the studies prefer single-use paper towels. Paper towels are more effective in drying the hands, removing bacteria, and decreasing the risk of environmental contamination. Besides, paper towels are quicker in drying the hands, which will reflect on saving more time.

From an airborne dissemination point of view, E.L.Best, P.Parnell, and M.H.Wilcoxab found that the bacterial count in an air sample in close proximity to electronic hand drying was 27-fold higher when comparing it with the use of paper towels. Those findings reflect that the risk of cross-contamination is more likely when electronic hand drying has been used. Besides, due to the noise associated with warm air-dryers, researchers conclude that those dryers are not suitable to be built in patients’ rooms or areas. These dryers can cause environmental and occupational hazards.

Finally, paper towels outperform electric air dryers from a hygienic point of view. Therefore, paper towels should be recommended in areas where sanitation is of the highest significance, such as hospitals and clinics,” ^{[1] [2]}  says Marwa. 

The counter-argument

Dyson, on the contrary, has conducted many tests on their products, which have shown them to be hygienic. “There is no evidence to support the claim that hand dryers spread around bacteria and viruses, and it’s important to note that some of the studies published that raise concerns around the topic do not employ methodology which represents real-world use. For example, some studies have contaminated participants’ hands by immersing them in solutions of unrealistically high concentrations of bacteria or viruses and then using a hand dryer without washing their hands first. They also skipped the step of attaching the microorganisms to the skin, as it would be seen in real life. Interestingly, new research commissioned by Dyson with an independent laboratory shows a comparable increase of bacteria in air and aerosols when hands are dried with paper towels or jet dryers. These results further support that Dyson Airblade technology is a safe and hygienic washroom solution to dry hands, says Salomé Giao, Senior Scientist at Dyson. 

Salomé further reiterates that hand washing is a crucial way of reducing the spread of bacteria and viruses, but drying hands is just as important as thoroughly washing them. “A Dyson Airblade hand dryer offers a safe and efficient solution to drying hands quickly. In the same research commissioned by Dyson, results also showed that the increase of aerosols and bacteria in air numbers after drying with any of the Dyson AirbladeTM hand dryer models is insignificant compared to walking and washing hands – which further supports its hygienic credentials. Crucially, Dyson Airblade technology is also touch-free. In a global hygiene study commissioned by Dyson, in July 2020, it was examined how attitudes and behaviors towards the washroom and general hand hygiene have changed since COVID-19 started. The study revealed that 40% of respondents worry about having to press buttons on hand dryers to use them, and 58% of those surveyed selected touchless activation of a hand dryer as one of the features that would put their mind at ease if using a hand dryer. At a time when hygiene is of paramount importance, Dyson Airblade hand dryers are an essential partner to support good hand hygiene,” she concludes.   

To summarize, although recent studies suggest that hand dryers do not promote hand hygiene, the question is whether these studies have been conducted under realistic conditions. There are both pros and cons of using hand dryers but whether using them is a resounding yes or not largely depends upon the facility in question. 

References: 

1. Best, E. L., Parnell, P., & Wilcox, M. H. (2014). Microbiological comparison of hand-drying methods: the potential for contamination of the environment, user, and bystander. Journal of Hospital Infection, 88(4), 199-206.‏
2. Huang, C., Ma, W., & Stack, S. (2012, August). The hygienic efficacy of different hand-drying methods: a review of the evidence. In Mayo Clinic Proceedings (Vol. 87, No. 8, pp. 791-798). Elsevier.‏