“Hand dryers ‘splatter’ users with bacteria,”
The headline is prompted by an experimental study that compared the potential transfer of germs to the surrounding environment, users and bystanders when using three methods of hand drying:
- paper towels
- warm air dryers – the sort you see in most public toilets
- modern “high-tech” jet air dryers, such as the Dyson Airblade model
Testers wore gloves coated in a solution of bacteria. Air samples taken after drying with the hand dryers showed significantly higher bacterial counts than when drying with paper towels, and were highest for the jet air dryers.
They then assessed the potential for spread to users and bystanders, this time using the proxy of gloves coated in black paint and a white body suit.
They found there was no contamination of the body after towel drying, but paint spots were on the body after the use of air dryers, which again was higher with jet dryers than standard warm air dryers.
One important limitation of this study is it essentially replicates the scenario of someone going to the toilet and then proceeding straight to the hand dryer without washing their hands first.
A more suitable test may have been to coat the gloves with the marker, wash them with soap and water as recommended, and then proceed to the hand dryers.
But the overall message of this study is consistent with current hand washing recommendations, including the use of disposable paper towels in healthcare settings.
Now wash your hands
The best way to wash hands is to:
- wet hands under running water, apply soap and rub this in thoroughly over all hand surfaces – this should be done for as long as it takes to sing a verse of “Happy Birthday” to yourself
- rinse completely
- dry hands thoroughly (at least 15 seconds), ideally with disposable paper towel – reusable towels or flannels should not be shared
- use a paper towel to turn the tap off to avoid re-contaminating your hands
The study was carried out by researchers from the University of Leeds and the microbiology department at Leeds General Infirmary.
It was funded by the European Tissue Symposium (ETS), from whom one author reports having received honoraria.
The ETS produces paper tissue, including toilet paper, household towels and paper napkins, which may be seen as a potential conflict of interest.
The study was published in the peer-reviewed Journal of Hospital Infection.