CDC H1N1 Flu Website Situation Update, March 27, 2010

Key Flu Indicators

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 14-20, 2010, nationally most key flu indicators remained about the same as during the previous week, however, increasing activity has been reported in certain areas. Below is a summary of the most recent key indicators:

• Visits to doctors for influenza-like illness (ILI) remained stable and relatively low nationally. However, ILI is also looked at by region, and three of 10 U.S. regions reported elevated ILI for the week ending March 20. Elevated ILI was seen in Regions 4, 7 and 9. Region 4 is comprised of Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and Tennessee. Region 7 is Iowa, Kansas, Missouri and Nebraska. And Region 9 is Arizona, California, Hawaii and Nevada. (Last week, only region 4 had elevated ILI.)
• Laboratory-confirmed hospitalizations rates have leveled off and very few hospitalizations were reported by states during the week ending March 20, however some states in the Southeast are reporting recent 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 increased over last week, but in general remains low nationally. One flu-related pediatric death was reported this week which was associated with an influenza A virus for which the subtype was undetermined. Since April 2009, CDC has received reports of 332 laboratory-confirmed pediatric deaths: 278 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 reported regional influenza activity. They are: Alabama, Georgia and South Carolina. Local and regional flu activity has been sustained in the Southeast of the United States 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. Some influenza B viruses are circulating at low levels, and these viruses remain similar to the influenza B virus component of the 2009-10 seasonal flu vaccine.

From CDC