USA Flu activity

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 October 4-10, 2009, a review of the key indictors found that influenza activity continued to increase in the United States from the previous week. Below is a summary of the most recent key indicators:

• Visits to doctors for influenza-like illness (ILI) continued to increase in the United States, and overall, are higher than what is expected for this time of the year. ILI activity now is equal to or higher than what is seen at the peak of many regular flu seasons.
• Total influenza hospitalization rates for laboratory-confirmed flu are climbing and are higher than expected for this time of year.
• The proportion of deaths attributed to pneumonia and influenza (P&I) based on the 122 Cities Report has increased and exceeds what is normally expected at this time of year. In addition, 11 flu-related pediatric deaths were reported this week; 10 of these deaths were confirmed 2009 H1N1, and one was influenza A virus, but unsubtyped. Since April 2009, there have been 86 confirmed pediatric 2009 H1N1 deaths; 39 of these have been reported to CDC since August 30, 2009.
• Fourty-one states are reporting widespread influenza activity at this time. They are: Alabama, Alaska, Arizona, Arkansas, California, Colorado, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Dakota, Texas, Tennessee, Utah, Virginia, Washington, West Virginia, Wisconsin, and Wyoming. This many reports of widespread activity are unprecedented during seasonal flu.
• Almost all of the influenza viruses identified so far are 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.

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