Actually, so we don't spread FUD, there is NOT some new mutation and no more potent offshoot of H1N1 out there. There's just the one strain and what we see in the US now and in the Southern Hemisphere is basically what first emerged last spring, so it's not mutating. At least not yet. Which is great as far as vaccine development is concerned, and it is still sensitive to anti-virals.

What that article was attempting to describe is the subset of illnesses that have occurred in younger folks that are particularly serious. H1N1 is relatively mild in most folks, but unlike the run-of-the-mill flu, H1N1 has produced very serious illness in some younger folks. Older folks have mostly been spared very serious illness, which is the opposite of what usually happens with seasonal flu.

The writer seems to have been using this WHO press release as the source document for this article. This same document clearly states: "Studies have detected no signs that the virus has mutated to a more virulent or lethal form."