How safe is safe?

We all know Sod's Law - "if it can go wrong, it will go wrong", but this is just an eye-catching way of presenting a much wider truth - if it can happen, it will happen. A thing - anything - is either impossible, in which case it can never happen under any circumstances, or it is possible, in which case, make no mistake, it will happen, sooner or later. Probability is a measure of how long we are likely to have to wait before it happens. It's worth bearing all this in mind when someone tells us that something is "safe". Following the death of a young lad from measles and a general increase in the disease, doctors are once again pushing the MMR jab and assuring us that it is safe. But this doesn't imply a complete absence of risk - simply that the risk can be regarded as negligible, and that the dangers associated with not having the jab are massively greater than those which may result from having it. This is what parents need to be aware of when making their decision.