DOCTORS and nurses take note – rubbing your hands together in a hand dryer leaves them coated with more bacteria than just after you washed them. Even normal skin bacteria may be bad news for sick people.

“When you rub your hands, you bring a lot of bacteria to the surface from the pores of your skin,” says Anna Snelling of the University of Bradford, UK. She asked 14 volunteers to dry their hands for 15 seconds using three different types of air dryer, sometimes rubbing their hands together and sometimes not.

When volunteers kept their hands still, the dryers reduced …