Week 45 presents with good news!  It appears that the U.S. is trending down and perhaps is seeing the movement towards the end of wave two.  Here is the summary for the week.

  • Over 99% of all subtyped influenza A viruses being reported to CDC were 2009 influenza A (H1N1) viruses.
  • The proportion of deaths attributed to pneumonia and influenza (P&I) was above the epidemic threshold for the seventh consecutive week.
  • 21 influenza-associated pediatric deaths were reported.
    • 15 of these deaths were associated with 2009 influenza A (H1N1) virus infection
    • 6 were associated with an influenza A virus for which the subtype was undetermined (remember that 99% of the virus is H1N1)
  • The proportion of outpatient visits for influenza-like illness (ILI) was 5.5% which is above the national baseline of 2.3%.
    • All 10 regions reported ILI above region-specific baseline levels.
  • 43 states reported geographically widespread influenza activity – this is down from 46 on week 44 and 48 week 43.
    • Puerto Rico and seven states reported regional influenza activity, the District of Columbia reported local influenza activity, and Guam and the U.S. Virgin Islands reported sporadic influenza activity.


Pneumonia and Influenza Hospitalizations and Deaths

Ahdr45 Small
From August 30 – November 14, 2009, 26,315 laboratory-confirmed influenza-associated hospitalizations and 1,049 laboratory-confirmed influenza-associated deaths were reported to CDC. CDC will continue to use its traditional surveillance systems to track the progress of the 2009-10 influenza season.


Outpatient Surveillance

Nationwide during week 45, 5.5% of patient visits reported through the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet) were due to influenza-like illness (ILI). This percentage is above the national baseline of 2.3%.

Notice that nice trending down for the past two weeks!  ;-)

Geographical Spread by State

Regional influenza activity was reported by Puerto Rico and seven states (Hawaii, Mississippi, Nebraska, North Dakota, South Carolina, Texas, and Wyoming). All other states reported widespread illness.

This is a week of good news…keep in mind however that a third wave is forecast and today also the first news of a documented mutation in Norway was made public…don’t fall asleep, stay vigilant.  With influenza anything is possible.