There are two main scenarios that I think are relevant.

The average human-being has something like 10,000,000 bacteria with representatives of maybe as much as 1,000 different species between their hands and elbows alone. Now, before you go off and panic scrub yourself with Domestos, the vast majority of that bacteria is perfectly normal, and even required by our bodies, so calm down.

Anyway, back to the ‘kills 99.999%’ claim. What exactly does that mean? Does it mean 99.999% of any and all bacteria that come into contact with this stuff dies, or just that it kills 99.999% of the species of bacteria it comes into contact with? If it’s the former, than that means 100 of the little blighters will survive. OK, you’ve wiped out the huge vast majority, but the ones that are left, oh boy are they gonna party, and have little bacteria babies like there is no tomorrow. If it’s the latter, then what if the species they leave behind are in the majority population wise and also the nasty ones? Furthermore, what of the good little bacteria that our bodies rely on to get much of its work done? Do we really want to go around indiscriminately killing them off?

Let me just be clear here, I’m not claiming that the hand sanitisers are a bad thing, nor that basic personal hygiene should be ignored. What I am saying however is that we shouldn’t always just take claims at face value, we should take it upon ourselves to actually understand what they mean, and possibly investigate how they were derived. The better educated you are, the better equipped you become to make important decisions.

Stay safe, and skeptical!