Each week CDC analyzes information about influenza disease activity in the United States and publishes findings of key flu indicators in a report called FluView. During the week of November 15-21, 2009, influenza activity decreased in some key indicators and increased in others. Overall influenza activity remains high for this time of year. Below is a summary of the most recent key indicators:
- Visits to doctors for influenza-like illness (ILI) nationally decreased sharply this week over last week with all regions showing declines in ILI. This is the fourth consecutive week of national decreases in ILI after four consecutive weeks of sharp increases While ILI has declined, visits to doctors for influenza-like illness remain high.
- Influenza hospitalization rates remain higher than expected for this time of year. Hospitalization rates continue to be highest in younger populations with the highest hospitalization rate reported in children 0-4 years old.
- The proportion of deaths attributed to pneumonia and influenza (P&I) based on the 122 Cities Report continues to be higher than expected for this time of year. This proportion has remained elevated for eight weeks now. In addition, 35 flu-related pediatric deaths were reported this week: 27 of these deaths were associated with laboratory confirmed 2009 H1N1; 7 were influenza A viruses, but were not subtyped and one death was associated with a seasonal influenza A (H1) virus. The one death associated with seasonal influenza A (H1) virus infection reported this week actually occurred in March, during the 2008-09 season. Since April 2009, CDC has received reports of 234 laboratory-confirmed pediatric deaths: 198 due to 2009 H1N1, 35 pediatric deaths that were laboratory confirmed as influenza, but the flu virus subtype was not determined, and one pediatric death associated with a seasonal influenza virus. (Laboratory-confirmed deaths are thought to represent an undercount of the actual number. CDC has provided estimates about the number of 2009 H1N1 cases and related hospitalizations and deaths.
- Thirty-two states are reporting widespread influenza activity at this time; a decline of 11 states from last week. They are: Alabama, Alaska, Arizona, California, Connecticut, Delaware, Florida, Idaho, Illinois, Indiana, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, Tennessee, Utah, Vermont, Virginia, and West Virginia).
- Almost all of the influenza viruses identified so far continue to be 2009 H1N1 influenza A viruses. These viruses remain similar to the virus chosen for the 2009 H1N1 vaccine, and remain susceptible to the antiviral drugs oseltamivir and zanamivir with rare exception.
*All data are preliminary and may change as more reports are received.
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Cases Defined by
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Hospitalizations
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Deaths
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|---|---|---|---|
| Influenza Laboratory-Tests** | 29,348 | 1,224 | |
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*Reports can be based on syndromic, admission or discharge data, or a combination of data elements that could include laboratory-confirmed and influenza-like illness hospitalizations. *Laboratory confirmation includes any positive influenza test (rapid influenza tests, RT-PCR, DFA, IFA, or culture), whether or not typing was done. The table shows aggregate reports of all laboratory confirmed influenza hospitalizations and deaths (including 2009 H1N1 and seasonal flu) since August 30, 2009 received by CDC from U.S. states and territories**. This table will be updated weekly each Friday at 11 a.m. For the 2009-2010 influenza season, states are reporting based on new case definitions for hospitalizations and deaths effective August 30, 2009. CDC will continue to use its traditional surveillance systems to track the progress of the 2009-2010 influenza season. For more information about influenza surveillance, including reporting of influenza-associated hospitalizations and deaths, see Questions and Answers: Monitoring Influenza Activity, Including 2009 H1N1. The number of 2009 H1N1 hospitalizations and deaths reported to CDC from April – August 2009 is available on the Past Situation Updates page. For state level information, refer to state health departments. International Human Cases of 2009 H1N1 Flu Infection **States report weekly to CDC either 1) laboratory-confirmed influenza hospitalizations and deaths or 2) pneumonia and influenza syndrome-based cases of hospitalization and death resulting from all types or subtypes of influenza. Although only the laboratory confirmed cases are included in this report, CDC continues to analyze data both from laboratory confirmed and syndromic hospitalizations and deaths. |
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Date Reported
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Laboratory-Confirmed 2009 H1N1 Influenza Pediatric Deaths
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Laboratory-Confirmed Influenza A Subtype Unknown Pediatric Deaths
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Laboratory-Confirmed
Seasonal Influenza | Total |
|---|---|---|---|---|
| This Week (Week 46, November 15-21, 2009) | 27 | 7 | 1 | 35 |
| Since August 30, 2009 | 140 | 32 | 0 | 172 |
| Cumulative since April 26, 2009 | 198 | 35 | 1 | 234 |
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This table is based on data reported to CDC through the Influenza-Associated Pediatric Mortality Surveillance System. Influenza-associated deaths in children (persons less than 18 years) was added as nationally notifiable condition in 2004. For more information about influenza-associated pediatric mortality, see FluView. |
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Source: cdc.gov
