FluView Week 1 ending January 5, 2013

[I will place last weeks information in brackets in green color, after this weeks information.  All editing below is mine.]

2012-2013 Influenza Season Week 1 ending January 5, 2013

As a result of the end of year holidays and elevated influenza activity, some sites may be experiencing longer than normal reporting delays and data in previous weeks are likely to change as additional reports are received.

Synopsis:

During week 1 (December 30-January 5), influenza activity remained elevated in the U.S., but may be decreasing in some areas.

• Viral Surveillance: Of 12,876 specimens tested and reported by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories, 4,222 (32.8%) were positive for influenza. 
  [Of 9,363 specimens tested and reported by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories, 2,961 (31.6%) were positive for influenza.]
• Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was slightly above the epidemic threshold.  [The proportion of deaths attributed to pneumonia and influenza (P&I) was below the epidemic threshold. ]
• Influenza-Associated Pediatric Deaths: Two influenza-associated pediatric deaths were reported. One was associated with an influenza A (H3) virus and one was associated with an influenza A virus for which the subtype was not determined. 
  [Two influenza-associated pediatric deaths were reported and were associated with influenza B viruses.]
• Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 4.3%; above the national baseline of 2.2%. Nine of 10 regions reported ILI above region-specific baseline levels. Twenty-four states and New York City experienced high ILI activity; 16 states experienced moderate ILI activity; 5 states experienced low ILI activity; 5 states experienced minimal ILI activity, and the District of Columbia had insufficient data. 
  [The proportion of outpatient visits for influenza-like illness (ILI) was 5.6%; above the national baseline of 2.2%. Nine of 10 regions reported ILI above region-specific baseline levels. New York City and 29 states experienced high ILI activity; 9 states experienced moderate ILI activity; 4 states experienced low ILI activity; 6 states experienced minimal ILI activity, and the District of Columbia and 2 states had insufficient data.]

Pneumonia and Influenza (P&I) Mortality Surveillance:

During week 1, 7.3% of all deaths reported through the 122 Cities Mortality Reporting System were due to P&I. This percentage was slightly above the epidemic threshold of 7.2% for week 1.

Influenza-Associated Pediatric Mortality:

Two influenza-associated pediatric deaths were reported to CDC during week 1. One was associated with an influenza A (H3) virus and occurred during week 52 (week ending December 29, 2012) and one was associated with an influenza A virus for which the subtype was not determined and occurred during week 1 (week ending January 5, 2013). This brings the total number of influenza-associated pediatric deaths reported during the 2012-2013 season to 20. Additional data can be found at http://gis.cdc.gov/GRASP/Fluview/PedFluDeath.html.

Influenza-Associated Hospitalizations:

The Influenza Hospitalization Surveillance Network (FluSurv-NET) conducts population-based surveillance for laboratory-confirmed influenza-related hospitalizations in children younger than 18 years of age (since the 2003-2004 influenza season) and adults (since the 2005-2006 influenza season).
The FluSurv-NET covers more than 80 counties in the 10 Emerging Infections Program (EIP) states (CA, CO, CT, GA, MD, MN, NM, NY, OR, TN) and additional Influenza Hospitalization Surveillance Project (IHSP) states. The IHSP began during the 2009-2010 season to enhance surveillance during the 2009 H1N1 pandemic. IHSP sites included IA, ID, MI, OK and SD during the 2009-2010 season; ID, MI, OH, OK, RI, and UT during the 2010-2011 season; MI, OH, RI, and UT during the 2011-2012 season; and IA, MI, OH, RI, and UT during the 2012-2013 season.

Data gathered are used to estimate age-specific hospitalization rates on a weekly basis, and describe characteristics of persons hospitalized with severe influenza illness. The rates provided are likely to be an underestimate as influenza-related hospitalizations can be missed, either because testing is not performed, or because cases may be attributed to other causes of pneumonia or other common influenza-related complications.
Between October 1, 2012 and January 5, 2013, 3,710 laboratory-confirmed influenza-associated hospitalizations were reported. This is a rate of 13.3 per 100,000 population. The most affected group is people ≥65 years. Among all hospitalizations, 3,198 (86.2%) were associated with influenza A and 484 (13.0%) with influenza B. There was no virus type information for 22 (0.6%) hospitalizations. Among hospitalizations with influenza A subtype information, 767 (98.7%) were attributed to H3 and 10 (1.3%) were attributed to 2009 H1N1. The most commonly reported underlying medical conditions among hospitalized adults were metabolic disorders, cardiovascular disease, obesity, and chronic lung disease (excluding asthma). Among 55 hospitalized women of childbearing age (15-44 years), 10 were pregnant. The most commonly reported underlying medical conditions in hospitalized children were asthma, neurologic disorders, and immune suppression. More than 40% of hospitalized children had no identified underlying medical conditions. Additional FluSurv-NET data can be found at: http://gis.cdc.gov/GRASP/Fluview/FluHospRates.html and http://gis.cdc.gov/grasp/fluview/FluHospChars.html.

These are only a few of the reports featues.  For the full document including many charts, click on the link below.  The weekly reports can be easily accessed by links provided on the right side-bar, scrolling down to Worldwide Update Influenza Activity.


http://www.cdc.gov/flu/weekly/