HealthBlawg is moving its RSS feed. If you ever read HealthBlawg in a feedreader such as Google Reader (which, by the way, is being shut down by Google July 1, so it's time to pick a new feedreader and migrate all of your feeds) then you need to subscribe to the feed at a new address:
Why don't you do it right now?
The posts in your feedreader will look exactly the same, though you may see some slight changes as of May 1. If you don't subscribe to the new feed, then after May 1 you may no longer see HealthBlawg posts in your feedreader. If you've let it slide until then you can always resubscribe by clicking on the RSS icon in the sidebar on the HealthBlawg home page.
You will see this reminder several times between now and May 1, but the sooner you take care of this — and the sooner you take care of migrating from Google Reader — the better.