ATLANTA—The latest H1N1 update from the Centers for Disease Control & Prevention (CDC) reveal the number of swine flu infections are seem to be dropping; however, the number of children who died with the illness rose by about 30. Overall influenza activity remains high for this time of year.
According to the report, visits to doctors for influenza-like illness (ILI) nationally decreased sharply this week over last week with all regions showing declines in ILI. This is the fourth 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 remain high. Influenza hospitalization rates remain higher than expected for this time of year. Hospitalization rates continue to be highest in younger populations with the highest hospitalization rate reported in children 0 to 4 years old.
The proportion of deaths attributed to pneumonia and influenza (P&I) based on the 122 Cities Report continues to be higher than expected for this time of year. This proportion has remained elevated for eight weeks now.
In addition, 35 flu-related pediatric deaths were reported this week—27 of these deaths were associated with laboratory confirmed 2009 H1N1; 7 were influenza A viruses, but were not subtyped and one death was associated with a seasonal influenza A (H1) virus. The one death associated with seasonal influenza A (H1) virus infection reported this week actually occurred in March, during the 2008-09 season. Since April 2009, CDC has received reports of 234 laboratory-confirmed pediatric deaths: 198 due to 2009 H1N1, 35 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. (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.
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.