U.S. Influenza Surveillance 2003-2004

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U.S. Influenza Surveillance2003-2004

• Ann Moen
• Influenza Branch
• NCID/CDC

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U.S. Influenza Surveillance
State and Territorial Epidemiologists
Sentinel Providers
Vital Statistics Registrars
Health Departments
CDC
Laboratories
Other
Public Health Officials
Public
Physicians
Media
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WHO/NREVSS Collaborating LaboratoriesNational
Summary, 2003-04
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The Viruses 2003-04 Influenza Season Week
ending February 7, 2004- week 5

• Total specimens tested by WHO and NREVSS
  laboratories in the U.S. 92,159
• Total positive for influenza 22,419 (24.3)
• Influenza A 22,286 (99.4) Influenza B 133
• Total subtyped 5,862 (26.3)
• A(H3N2) 5,861 (99.9) and A(H1)1
• Subset characterized at CDC

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Percentage of Specimens Testing Positive for
Influenza National Summary, 2003-04
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Percentage of Visits for Influenza-like
IllnessReported by Sentinel ProvidersNational
Summary, 2003-04
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U.S. Sentinel Providers Reporting Summary as of
February 13, 2004

• 1931 SPs enrolled
• 1141 regularly reporting
• 19,727 reports received (19 weeks)
• 5,581,022 patient visits recorded
• 169,919 reports of ILI

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Pneumonia and Influenza Mortality for 122 U.S.
CitiesWeek Ending 02/07/04
Epidemic Threshold
Seasonal Baseline
2000
2001
2002
2003
10 20 30 40 50 10 20
30 40 50 10 20 30 40
50 10 20 30 40 50
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Weekly Influenza Activity Estimates Reported by
State Territorial Epidemiologists Week ending
October 4, 2003 - Week 40
No Report
Sporadic
Regional
Widespread
No Activity
Local Activity
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Changes in Activity Reports from State
Territorial Epidemiologists

• Previous Years
• 4 levels of activity
• None, sporadic, regional, widespread
• Based on percentage of population counties
• Criteria used either outbreaks of culture
  confirmed influenza or ILI

• 2003-2004
• 5 levels of activity
• None, sporadic, local, regional, widespread
• Based on state defined regions
• Defined criteria uses combination of
  ILI/outbreaks and laboratory data
• Specified time frames for lab confirmation

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Weekly Influenza Activity Estimates Reported by
State Territorial Epidemiologists Week ending
December 20, 2003 - Week 51
No Report
Sporadic
Regional
Widespread
No Activity
Local Activity
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Peak of Influenza Activity as Reported by State
Territorial Epidemiologists 1999-2000
Season Week ending January 15, 2000 - Week 2
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Peak of Influenza Activity as Reported by State
Territorial Epidemiologists 2002-03
Season Week ending March 1, 2003 - Week 9
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Summary of the 2003-04 Influenza Season