Thanks for the link. I guess it does look roughly like the trends for the flu, though honestly neither one looks like a saddle to me. A saddle is much more symmetrical, and these look more like linear functions with a small blip on the far left side.

I'd still be interested to know if the 0-4 age group has homogeneous risk, or if the real risk is among 0-6 (or 12) month old babies. I have a 2 year old and we have been very cautious, but haven't seen any evidence that kids this age are at much risk for serious illness or death.