H1N1 Flu: Situation Update, April 9, 2010

Atlanta, GA–(ENEWSPF)–April 9, 2010. 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 March 28-April 3, 2010, nationally most key flu indicators declined slightly from the previous week. Overall, influenza activity is low in the United States. Below is a summary of the most recent key indicators:

Visits to doctors for influenza-like illness (ILI) declined from last week and are low nationally with all 10 U.S. regions seeing declining or stable ILI. (Last week, Region 9 — the Southwest and Hawaii — had elevated ILI.)
Laboratory-confirmed hospitalizations rates have leveled off and very few hospitalizations were reported by states during the week ending April 3; however, in recent prior weeks, some states – mostly in the Southeast of the country – had been reporting increases in the number of flu-related hospitalizations.
The proportion of deaths attributed to pneumonia and influenza (P&I) based on the 122 Cities Report decreased over last week and is now below baseline. One flu-related pediatric death was reported this week associated with an unsubtyped influenza A virus. Since April 2009, CDC has received reports of 334 laboratory-confirmed pediatric deaths: 280 due to 2009 H1N1, 52 pediatric deaths that were laboratory confirmed as influenza A, 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).
No states reported widespread influenza activity. Three states continue to report regional influenza activity. They are: Alabama, Georgia and South Carolina. Local and regional flu activity has been sustained in most of the Southeast over the past several weeks.
The majority 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 2009 to April 3, 2010
Posted April 9, 2010, 11:00 AM ET
Data reported to CDC by April 6, 2010, 12:00 AM ET
Cases Defined by	Hospitalizations	Deaths
Influenza Laboratory-Tests**	41,821	2,117
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 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 April 9, 2010 (Updated Weekly)
Data reported to CDC by April 3, 2010
Date Reported	Laboratory-Confirmed 2009 H1N1 Influenza Pediatric Deaths	Laboratory-Confirmed Influenza A Subtype Unknown Pediatric Deaths	Laboratory-Confirmed Seasonal Influenza	Total
This Week (Week 13, March 28 – April 3, 2010)	0	1	0	1
Since August 30, 2009	220	49	1	270
Cumulative since April 26, 2009	280	52	2	334
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.