Saturday, December 29, 2012

CDC FluView Week 51

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# 6809

 


With the Christmas holidays each year usually comes some delays in surveillance and reporting on influenza, so this week we have no FluWatch report from Canada.  According to an email sent by PHAC, `data for weeks 51 and 52 will be published in a combined report on Friday, 4 January 2013.’

 

The CDC’s FluView report, issued on Friday, reflects a drop in the number of influenza-positive tests reported by the WHO/NREVSS collaborating laboratories, but this is likely more an artifact of reduced holiday testing & reporting than a significant drop in flu activity.

INFLUENZA Virus Isolated

A summary of this weeks FluView Report states:

012-2013 Influenza Season Week 51 ending December 22, 2012

All data are preliminary and may change as more reports are received.

Synopsis:

During week 51 (December 16-22), influenza activity increased in the U.S.

  • Viral Surveillance: Of 6,234 specimens tested and reported by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories in week 51, 1,846 (29.6%) were positive for influenza.
  • Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below the epidemic threshold.
  • Influenza-Associated Pediatric Deaths: Eight influenza-associated pediatric deaths were reported. Three were associated with influenza B viruses, 3 were associated with influenza A (H3) viruses, and 2 were associated with influenza A viruses for which the subtype was not determined.
  • Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 4.2%; above the national baseline of 2.2%. Nine of 10 regions reported ILI above region-specific baseline levels. New York City and 16 states experienced high ILI activity; 8 states experienced moderate ILI activity; 10 states experienced low ILI activity; 14 states experienced minimal ILI activity, and the District of Columbia and 2 states had insufficient data.
  • Geographic Spread of Influenza: Thirty-one states reported widespread geographic influenza activity; 14 states reported regional activity; the District of Columbia and 3 states reported local activity; 2 states reported sporadic activity; Guam reported no influenza activity, and Puerto Rico and the U.S. Virgin Islands did not report.

While flu activity (red line) remains lower (so far) than the peak we saw during the moderately severe 2007-08 season (blue line), the following chart illustrates the early start to the season.

 

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The number of pediatric influenza fatalities jumped by 8 this week, to a total of 16 this year, and  Pneumonia and Influenza (P&I) Mortality remains below the epidemic level. Both of these numbers tend to be lagging indicators, however.

 

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While flu season is certainly underway across much of the nation, some states have yet to report significant activity.

 

The peak of the season may still be a month or more away, meaning there is still time to get that flu shot. Earlier this week  the CDC sent out the following reminder:

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