H1N1 Virus (Swine Flu)

2009 H1N1 Flu: Situation Update, December 24, 2009

Atlanta, GA–(ENEWSPF)–December 24, 2009.

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 December 13-19, 2009, influenza activity decreased over the previous week across most key indicators. Below is a summary of the most recent key indicators:

  • Visits to doctors for influenza-like illness (ILI) nationally decreased slightly again this week over last week. This is the eighth consecutive week of national decreases in ILI however visits to doctors for ILI remains elevated in the United States.
  • Influenza hospitalizations and hospitalization rates decreased in all age groups.
  • Deaths attributed to pneumonia and influenza (P&I) based on the 122 Cities Report decreased over the previous week. This is the first time in 11 weeks that this proportion has been below the epidemic threshold. (The epidemic threshold is the point at which the observed proportion of deaths attributed to pneumonia or influenza is significantly higher than would be expected at that time of the year in the absence of substantial influenza-related mortality.) In addition, nine flu-related pediatric deaths were reported this week: eight of these deaths were associated with laboratory confirmed 2009 H1N1, and one was associated with an influenza A virus that was not subtyped. Since April 2009, CDC has received reports of 285 laboratory-confirmed pediatric deaths: 241 due to 2009 H1N1, 42 pediatric deaths that were laboratory confirmed as influenza, but the flu virus subtype was not determined, and two pediatric deaths that were associated with seasonal influenza viruses. (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.
  • Seven states continue to report widespread influenza activity; a decline of four states from last week. They are: Alabama, California, Delaware, Maine, Nevada, New Jersey, and Virginia. Eighteen states are reporting regional influenza activity and 13 states and the District of Columbia and Puerto Rico are reporting local influenza activity.
  • 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.

Laboratory Confirmed Influenza-Associated Hospitalizations
and Deaths from August 30 to December 19, 2009
Posted December 24, 2009, 11:00 AM ET
Data reported to CDC by December 22, 2009, 12:00 AM ET
Cases Defined by
Influenza Laboratory-Tests** 36,163 1,630

*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 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
See: World Health Organization

**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.

U.S. Influenza-associated Pediatric Mortality
Posted December 24, 2009 (Updated Weekly)
Data reported to CDC by December 19, 2009
Date Reported
Laboratory-Confirmed 2009 H1N1 Influenza Pediatric Deaths
Laboratory-Confirmed Influenza A Subtype Unknown Pediatric Deaths
This Week (Week 50, December 13-19, 2009) 8 1 0 9
Since August 30, 2009 181 39 1 221
Cumulative since April 26, 2009 241 42 2 285

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.

Source: cdc.gov

Summer and Fall at Prairie State College