@Khandro
//However vacuum cleaning a carpet, whatever the make of cleaner, is more hygienic than sloshing around vinyl tiles with a mop and bucket as I've seen done in UK hospitals. //
Never heard of Dettol, Dettox, or bleach, then?
Admittedly, vacuuming will remove all the dead skin cells, grit and other powdery substances from the soles of your footwear but cannot guarantee the removal of well entrenched bacteria. However, in order for it to be that well protected from suction, they'd be so deep in the weave that your fingers wouldn't come into direct contact with them.
The problem for hospitals is that they have to deal, routinely, with fluid spillages. Bloodstains would ruin any carpet and using matching red, to avert such problems, would only make life impossible for the blood cleanup team.