H1N1 Swine Flu – Have we started the second wave yet? What is happening now?

September 20, 2009

The CDC has always published a weekly report on the state of influenza in the US…this is called the Flu View Synopsis.

Week 36 of Influenza in the US...note the unusual activity!
Week 36 of Influenza in the US...note the unusual activity!

Of course now it is ever more interesting as we are now into the first few weeks of  the second wave of the H1N1 pandemic…during week 36 (September 6-12, 2009), influenza activity increased in the U.S.

We are in week four of wave two!
Look at the red vertical line - we are in week four of wave two! BTW, the green was the 2007-2008 seasonal flu spike.
  • 99% of all subtyped influenza A viruses being reported to CDC were 2009 influenza A (H1N1) viruses.
image361
The gold bars are H1N1.
  • The proportion of deaths attributed to pneumonia and influenza (P&I) was below the epidemic threshold.
  • Two influenza-associated pediatric deaths were reported, and both were associated with 2009 influenza A (H1N1) virus infection.
  • The proportion of outpatient visits for influenza-like illness (ILI) was above the national baseline. Regions 2, 4, 5, 6, 7, 9, and 10 reported ILI above region-specific baseline levels.
It is easier to note which areas aren't above the normal - 1, 2 and 8 report below normal influenza activity.
It is easier to note which areas aren't "above normal" flu activity - 1, 2 and 8 report below normal influenza activity.
  • Twenty-one states reported geographically widespread influenza activity, nine states and Puerto Rico reported regional influenza activity, 11 states and the District of Columbia reported local influenza activity, eight states and Guam reported sporadic influenza activity, one state reported no influenza activity, and the U.S. Virgin Islands did not report.

Oh and by the way…The 2009-10 influenza season officially begins October 4, 2009.

Flu View http://www.cdc.gov/flu/weekly/