Everybody carries them around these days. Those tiny little hand sanitizers certainly come in handy after a ride on the subway or a trip through the airport, and they fit conveniently into my European man-bag. (Okay fine, it's a purse. I carry a purse.)

The instructions on the bottle I am carrying (which, as it so happens, comes from Bath & Body Works and beautifully matches my European man-bag purse) say: "Rub a dime sized drop into hands." Most people hardly do even that. At most, people stingily squeeze the tiniest of drops onto their hands in order to make their travel-sized antiseptic last as long as possible. 

But new research shows this is hardly sufficient. Even the dime-sized...