Google said it would have a health-related announcement at today's Google Press Day -- but no, it's not Google Health. Instead, it's Google Coop, a way for people to create specialized search filters within the Google database (including for health information) plus the option for searchers to pick preferred vertical search providers to show up in Google OneBox results. Info is to be going up soon here. I'll be updating this post shortly.
Postscript: Please see the fresh, long story I've now posted, Google Co-op: Add Your Own Vertical Search To Google.