The basic principle is that hand sanitizers are applied externally. They can be far more agressive than, say, antibiotics because they do not enter the body (or

The basic principle is that hand sanitizers are applied externally. They can be far more agressive than, say, antibiotics because they do not enter the body (or only in minimal quantities). The skin is a specialized, multi-layered protective structure that single-celled organisms just cannot replicate within their constraints (ability to absorb food, energy investment, etc). It's not quite good enough to allow the sort of methods completely immune against evolved resistance (fire, sufficient radiation, etc.). But it's far enough ahead to make it manageable. So I wouldn't worry too much. The worst outcome is likely to be hand-washing becoming a somewhat larger nuisance, a higher risk of skin irritation or some combination therefore. The whole procedure is probably ripe for some purely mechanical innovation such as high(ish) pressure water or air, considering that part hasn't much changed in the last 200 years (although training and frequency have increased)