Jet-air hand dryer argument blown away by bacteria study
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Using paper towels to dry hands after visiting the bathroom is “substantially” more effective than jet dryers for removing microbes, a study has claimed.
With people being urged to wash their hands as much as possible to minimise the risk of contracting Covid-19, hand drying has suddenly become a hot topic.
Failure to remove the microbes increases the risk that they will transfer to environmental surfaces, exacerbating the transmission and spread of diseases.
In a University of Leeds study, four volunteers simulated contamination of their hands/gloved hands using a bacteriophage, a virus that infects bacteria and thus is harmless to humans.
Their hands were not washed after contamination in order to simulate poorly or inadequately washed hands.
The participants' hands were dried using either paper towels (PT) or a jet air dryer (JAD). Each volunteer wore an apron, to enable measurement of body/clothing contamination during hand drying. Hand drying was performed in a hospital public toilet and, after exiting, samples were collected from public and ward areas.
The samples included doors, stairs handrails, lift buttons, chairs in public and ward areas, phones, buttons on access intercoms to wards, and stethoscope tubing.
The team found that both JAD and PT methods statistically significantly reduced virus contamination of hands, but for 10 out of the 11 surfaces studied significantly greater environmental contamination was detected after JAD versus PT use.
All surfaces sampled following JAD use showed phage contamination, compared with only 6 surfaces after PT use. Average surface contamination following hand contact was more than 10 times higher after JAD versus PT use.
This suggests transference of microbes to environmental surfaces can occur directly from hands that remain contaminated after hand drying, but also indirectly from a person’s body that has itself been contaminated during hand drying.
“There are clear differences, according to hand-drying method, in the residual microbial contamination of the subject’s hands and body,” the authors said. “Crucially, these differences in contamination translate into significantly greater levels of microbe contamination after jet air drying versus paper towel use from hands and body beyond the toilet/washroom.
“As public toilets are used by patients, visitors and staff, the hand-drying method chosen has the potential to increase (using jet dryers) or reduce (using paper towels) pathogen transmission in hospital settings.”
The team said their findings are of particular importance considering the general migration away from paper towels to jet hand dryers in many parts of the world, especially within healthcare environments in the UK.
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