CDC: H1N1 Flu Update

ATLANTA—The latest H1N1 update from the Centers for Disease Control & Prevention (CDC) reveal the number of swine flu infections continue to drop and 25 states report widespread activity, mostly in the Northeast and Southwest.

According to the report, visits to doctors for influenza-like illness (ILI) nationally decreased again this week over last week. This is the fifth consecutive week of national decreases in ILI after four consecutive weeks of sharp increases. While ILI has declined, visits to doctors for influenza-like illness still remain elevated nationally.

Influenza hospitalization rates have decreased across all age groups but remain higher than expected for this time of year. Though declining, hospitalization rates continue to be highest in children 0-4 years old.

The proportion of deaths attributed to pneumonia and influenza (P&I) based on the 122 Cities Report declined over the previous week, but continues to be higher than expected for this time of year. This is the ninth consecutive week that the proportion of deaths attributed to pneumonia and influenza (P&I) has been above the epidemic threshold.

In addition, 17 flu-related pediatric deaths were reported this week—12 deaths were associated with laboratory confirmed 2009 H1N1 and five were associated with influenza A viruses, but were not subtyped. Since April 2009, CDC has received reports of 251 laboratory-confirmed pediatric deaths—210 due to 2009 H1N1, 40 pediatric deaths that were laboratory confirmed as influenza, but the flu virus subtype was not determined, and one pediatric death associated with a seasonal influenza virus.

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.