N1H1 Statistics Update Week 43 US and Worldwide

2009-2010 Influenza Season Week 43 ending October 31, 2009

Synopsis:

During week 43 (October 25-31, 2009), influenza activity remained elevated in the U.S.

• 5,258 (37.2%) specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division were positive for influenza.
• 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.
• Eighteen influenza-associated pediatric deaths were reported. Fifteen of these deaths were associated with 2009 influenza A (H1N1) virus infection and three were associated with an influenza A virus for which the subtype was undetermined.
• The proportion of outpatient visits for influenza-like illness (ILI) was above the national baseline. All 10 regions reported ILI above region-specific baseline levels.
• Forty-eight states reported geographically widespread influenza activity, two states reported regional influenza activity, the District of Columbia reported local influenza activity; Puerto Rico and Guam reported sporadic influenza activity, and the U.S. Virgin Islands did not report.

The vaccine for the 2009-2010 seasonal influenza contains:

• an A/Brisbane/59/2007 (H1N1)-like virus
• an A/Brisbane/10/2007 (H3N2)-like virus
• a B/Brisbane/60/2008-like virus

U.S. Virologic Surveillance:

WHO and NREVSS collaborating laboratories located in all 50 states and Washington D.C., report to CDC the number of respiratory specimens tested for influenza and the number positive by influenza type and subtype. The results of tests performed during the current week are summarized in the table below.

	Week 43
No. of specimens tested	14,151
No. of positive specimens (%)	5,258 (37.2%)
Positive specimens by type/subtype
Influenza A	5,244 (99.7%)
A (2009 H1N1)	3,889 (74.2%)
A (subtyping not performed)	1,310 (25.0%)
A (unable to subtype)	41 (0.8%)
A (H3)	2 (0.0%)
A (H1)	2 (0.0%)
Influenza B	14 (0.3%)

During week 43, seasonal influenza A (H1), A (H3), and B viruses co-circulated at low levels with 2009 influenza A (H1N1) viruses. Over 99% of all subtyped influenza A viruses reported to CDC this week were 2009 influenza A (H1N1) viruses.

View WHO-NREVSS Regional Bar Charts| View Chart Data | View Full Screen

I don’t think the CDC should include the Influenza A (subtype not preformed) with the H1N1 confirmed cases (view full screen). It makes the numbers inaccurate. Week 43 deaths are roughly 100.

Pneumonia and Influenza Hospitalization and Death Tracking:

This new system was implemented on August 30, 2009, and replaces the weekly report of laboratory confirmed 2009 H1N1-related hospitalizations and deaths that began in April 2009. Jurisdictions can now report to CDC either laboratory confirmed or pneumonia and influenza syndromic-based counts of hospitalizations and deaths resulting from all types or subtypes of influenza, not just those from 2009 H1N1 influenza virus. To allow jurisdictions to implement the new case definition, counts were reset to zero on August 30, 2009. From August 30 – October 10, 2009, 4,958 laboratory-confirmed influenza associated hospitalizations, 292 laboratory-confirmed influenza associated deaths, 15,696 pneumonia and influenza syndrome-based hospitalizations, and 2,029 pneumonia and influenza syndrome-based deaths, were reported to CDC. CDC will continue to use its traditional surveillance systems to track the progress of the 2009-10 influenza season.

*I’m very concerned that changing the tracking system and all the cases not tested will lead to faulty numbers. CBS already reported the CDC’s numbers were off. This will probably make it worse.

Canada’s H1N1 numbers can be found at FluWatch.

WHO: Pandemic (H1N1) 2009 - update 73

Weekly update

As of 1 November 2009, worldwide more than 199 countries and overseas territories/communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 6000 deaths.

Basic Statistics:

* U S population over 304,059,724 (July 2008)

* World Population 6,706,993,152 (estimated July 2008)

*US Census Bureau: The total number of children under age 5 was 21 million in 2008, or 6.9 percent of the total population, compared with 19.2 million and 6.8 percent in 2000.

*Consider pediatric deaths from H1N1 in the US out of a population of 21,000,000.

*Over 6,000 reported deaths worldwide out a population of over 6,700,000,000.