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 27, 2009-January 2, 2010, most key indicators declined compared to the previous week. Below is a summary of the most recent key indicators:
- Visits to doctors for influenza-like illness (ILI) nationally decreased this week over last week. Visits to doctors for ILI also are examined by region. ILI increased in 4 regions, but decreased in 6 regions of the country.
- Overall hospitalization rates for this season were unchanged from the previous week in all age groups.
- The proportion of deaths attributed to pneumonia and influenza (P&I) based on the 122 Cities Report decreased over the previous week and is back 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, another four flu-related pediatric deaths were reported this week: all four of these deaths were associated with laboratory confirmed 2009 H1N1. Since April 2009, CDC has received reports of 293 laboratory-confirmed pediatric deaths: 248 due to 2009 H1N1, 43 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.
- One state (Alabama) continues to report widespread influenza activity; a decline of three states from last week. Twelve states continue to report regional influenza activity. They are: California, Georgia, Hawaii, Indiana, Maine, Nevada, New Hampshire, New Jersey, New Mexico, New York, Tennessee, and 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.