Google "jet air dryers" and you will find more than 100 articles about a recent study claiming that jet air dryers dispersed 60 times more "germs" than warm air dryers and 1300 times more "germs" than paper towels.
Here are a few of the juicier headlines:
It wasn't about germs. The study involved measuring the dispersal of a benign virus from the hands of research subjects at various distances and heights from the different hand drying methods.
So what's wrong with it?
Let's start with the methods. From the paper: "Participants were asked to rinse their gloved hands in 50 mL of the phage [virus] suspension for 10 seconds and simulate the process of washing [emphasis added] during this period followed by shaking three times and then drying them using one of the hand drying devices."
This is somewhat unrealistic since the subjects wore gloves, very few people dip their hands in a virus suspension for even 1 second let alone 10, and although I've seen several people simulate washing their hands in a restroom, many do wash.
This study reminded me of one that I blogged about two years ago. For that paper, subjects dipped their gloved hands in bacteria and paint and again did not wash them. Not surprisingly, the jet air dryers sprayed a lot more paint around the room than did paper towels.
That 2014 study was funded by the European Tissue Symposium. At the time I wrote " Although this sounds like some kind of scientific conference, it is actually a trade organization of companies that make paper towels."
If you go to the publisher's website and look at the abstract of the 2016 "germ" paper and click on "Funding Information," you'll find that the study was funded by the University of Westminster. But if you read the entire paper, at the end you will see that one of the authors "has received honoraria from the European Tissue Symposium for microbiological advice and travel expenses to attend meetings and conferences."
I read stories about the 2016 paper on several websites. None questioned the methods or mentioned the funding and only two contacted the the jet air dryer manufacturer for comments.
I guess you get more clicks with headlines like this one from UPROXX:
This is somewhat unrealistic since the subjects wore gloves, very few people dip their hands in a virus suspension for even 1 second let alone 10, and although I've seen several people simulate washing their hands in a restroom, many do wash.
This study reminded me of one that I blogged about two years ago. For that paper, subjects dipped their gloved hands in bacteria and paint and again did not wash them. Not surprisingly, the jet air dryers sprayed a lot more paint around the room than did paper towels.
That 2014 study was funded by the European Tissue Symposium. At the time I wrote " Although this sounds like some kind of scientific conference, it is actually a trade organization of companies that make paper towels."
If you go to the publisher's website and look at the abstract of the 2016 "germ" paper and click on "Funding Information," you'll find that the study was funded by the University of Westminster. But if you read the entire paper, at the end you will see that one of the authors "has received honoraria from the European Tissue Symposium for microbiological advice and travel expenses to attend meetings and conferences."
I read stories about the 2016 paper on several websites. None questioned the methods or mentioned the funding and only two contacted the the jet air dryer manufacturer for comments.
I guess you get more clicks with headlines like this one from UPROXX:
2 comments:
While the study is no doubt flawed, I prefer paper towels.
In the first place, the jet dryers do a poor job of drying my hands
and take a lot longer to dry them than paper towels. And in the second place, I prefer to open the bathroom door with a paper towel to avoid touching the door handle which has no doubt been
smeared with an interesting variety of bacteria deposited on the doorknob by those who did not wash their hands.
As I said in the 2014 post on this subject, I prefer paper towels too. But I also prefer research that makes sense.
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