I've noted several times here how more measured heads keep emphasizing that a) we're working on partial information in responding to the current swine flu outbreak and b) new developments may complicate things at any point along the line.
Here's a great example of what these folks (like Effect Measure, Crof, and Avian Flu Diary) are talking about.
Second strain of flu may complicate picture-study
06 May 2009 15:02:09 GMTBy Maggie Fox, Health and Science Editor
WASHINGTON, May 6 (Reuters) - A second strain of influenza, one of the seasonal strains, may have mutated and may be complicating the picture in Mexico, Canadian researchers reported on Wednesday.
They have found a strain of the H3N2 virus that appears to have made a shift and could have complicated the flu picture in Mexico, epicenter of an outbreak of a new strain of the H1N1 swine flu virus.
One was seen in a traveler returning from Mexico, the team at the British Columbia Centre for Disease Control reported to Pro-MED, an online forum for infectious disease experts. And it may have been involved in an unusually late outbreak of flu in long-term care facilities this year.
Catch the whole thing at AlertNet