Monday, March 18, 2013

CDC/ECDC/PHAC: Influenza Surveillance Week 10



# 7010


While flu activity continues in the Northern hemisphere, in most regions it is on the decline.  A few snippets this morning from the latest CDC, ECDC, and PHAC surveillance reports.


From the latest CDC FluView report:


2012-2013 Influenza Season Week 10 ending March 9, 2013

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


During week 10 (March 3 – 9, 2013), influenza activity remained elevated in the United States, but decreased in most areas.

  • Viral Surveillance: Of 5,747 specimens tested and reported by collaborating laboratories, 821 (14.3%) were positive for influenza.
  • Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was above the epidemic threshold.
  • Influenza-Associated Pediatric Deaths: Twelve pediatric deaths were reported.
  • Influenza-Associated Hospitalizations: A cumulative rate for the season of 39.6 laboratory-confirmed influenza-associated hospitalizations per 100,000 population was reported. Of reported hospitalizations, 51% were among adults 65 years and older.
  • Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 2.6%. This is above the national baseline of 2.2%. Six of 10 regions reported ILI at or above region-specific baseline levels. Five states and New York City experienced moderate activity; 12 states experienced low activity; and 33 states and the District of Columbia experienced minimal activity.
  • Geographic Spread of Influenza: Eight states reported widespread influenza activity; Puerto Rico and 19 states reported regional influenza activity; the District of Columbia and 17 states reported local influenza activity; 6 states reported sporadic influenza activity; Guam reported no influenza activity, and the U.S. Virgin Islands did not report.



From Canada, the latest FluWatch Report:



Overall Summary

  • Overall detections of influenza continued to decline, however the proportion of influenza B detections increased.
  • In week 10, 75% of paediatric hospitalizations were associated with influenza B.
  • Nationally, the number of regions reporting widespread or localized activity decreased.
  • The ILI consultation rate increased but was within the expected range for this time of year.



And last stop, the ECDC’s WISO Surveillance Report:



Substantial influenza activity in Europe but many countries report declining transmission: ECDC weekly monitoring

15 Mar 2013


During week 10, 18 of the 27 countries reporting indicated wide geographic spread on influenza, 16 of which also reported high/medium-intensity transmission, states the Weekly influenza surveillance overview. Only one country reported an increasing trend, and 19 countries reported a decreasing trend in influenza activity.


Virological surveillance shows that the overall proportion of influenza-positive cases among sentinel specimens continues to remain high (54%), but it has decreased from the peak observed in early February.


Since week 40/2012, 48% of sentinel specimens positive for influenza virus have been of type A and 52% of type B. The proportion of A(H1)pdm09 has remained at about 60% of subtyped type A viruses.


ECDC published its annual risk assessment for seasonal influenza 2012-13 in early February based on data up to week 3/2013.



Meanwhile, even though the flu season in the temperate regions of the Southern Hemisphere doesn’t typically begin until May or June, Australia and New Zealand have already begun to gird themselves.


A couple of examples of newspaper headlines over this past weekend include:


Flu shot push for pregnant women and elderly


Medical experts warn of US-style early and severe flu epidemic: Australians urged to get a flu vaccination from March 15

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