I took notice of that passage also. But the main reason the 99.5 to 99.95 percentages is meaningful is that they were measures of a daily risk. So it quickly compounds into a meaningful percentages; the 99.95% rate meant an 83% chance patient would stay well this year, the 99.5% rate meant only a 16% chance of staying well for this year.

Many of the medical percentages that we see quoted in media are derived using a lifetime risk basis, _not_ a daily one. On a lifetime basis the difference between 99.95% and 99.5% _is_ negligible.

I wonder how many people reading this article are aware of the difference.