A recent study by a team at the University of Leeds, UK was set up to determine if using paper towels or air dryers is more effective for removing microbes when still contaminated hands are dried.
Hand drying is especially critical in helping minimize the spread of dangerous microbes which includes COVID-19. Failure to remove these microbes increases their transfer to environmental surfaces which increases the opportunity for them to be transmitted and spread. The study set out to investigate whether there are differences in the extent of transmission of the virus according to each hand drying method beyond the bathroom to the hospital environment.
Four participants simulated contamination of their hands/gloved hands using a bacteriophage which is a virus that infects bacteria and is actually harmless to humans. Their hands were not washed after contamination as the method used to simulate poorly and inadequately hand washing. Their hands were dried using either paper towels or a jet air dryer. Each participant wore an apron to enable measurement of body/clothing contamination during hand drying. The hand drying was performed in a hospital bathroom and after the participants exited, samples were collected from both ward and public areas.
Environmental surface sites were sampled following participant’s contact with hands or apron. These site samples included doors, stair handrails, chairs in ward and public areas, lift buttons, phones, buttons on intercoms to wards, stethoscope tubing and head piece and chest piece, the aprons, and armchairs that had been indirectly in contact with aprons. For the latter sample site, the participants were asked to cross their arms across their chest while using the apron and before resting their arms on the chair.
The study team found that both paper towel and air dryer methods statistically significantly reduced virus contamination of hands. For 10 out of 11 surfaces tested, significantly greater environmental contamination was detected after air dryers versus paper towel use. All surfaces sampled following the use of air dryers showed phage contamination compared to 6 surfaces after paper towel use. Average surface contamination following hand contact was more than 10 times higher after air dryer use versus paper towel use.
Viral dispersal to apron/clothing was 5 times higher with air dryers versus the paper towels. Phage transfer from aprons to armchairs via the crossed arms was detected only following air dryer use. This suggests that the transfer of microbes to environmental surfaces can occur directly from hands that remain contaminated after air drying, but also indirectly from a person’s body that has been contaminated during air drying.
The research team concluded that there are very distinct differences in regards to air drying versus paper towel drying in the residual microbial contamination of the participant’s hands and body. These differences in contamination translate into significantly greater levels of microbe contamination after air drying versus the use of paper towels from hands and body beyond the bathroom. Since public bathrooms are used by patients, visitors and staff, the hand drying method used has the potential to increase (using air dryers) or reduce (using paper towels) pathogen transmission in hospitals.
The team also notes that their findings have significant importance since there has been a general migration from use of paper towels to more air drying in many settings and areas in the world. The World Health Organization’s hand washing guidelines recommend the use of paper towels to dry hands. And they also recommend using a paper towel to turn off the tap. Paper towels should be the preferred method of drying hands following proper washing to help reduce the risk of virus contamination and spread.
To view the original scientific study click below