Influenza activity remains near the same levels as reported over the past several week; below normal.
There are some signs of increasing activity in 3 of the 10 U.S. Regions (4,7, and 9), and there has been a slight uptick in the P&I mortality rate, but it still remains below the epidemic threshold for this time of year.
A few excerpts, then, from today’s FluView report. Follow the link to read it in its entirety.
All data are preliminary and may change as more reports are received.
During week 11 (March 14-20, 2010), influenza activity remained at approximately the same levels as last week in the U.S.
- 139 (4.6%) specimens tested by U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories and reported to CDC/Influenza Division were positive for influenza.
- Approximately 99% of all subtyped influenza A viruses reported to CDC were 2009 influenza A (H1N1) viruses.
- The proportion of deaths attributed to pneumonia and influenza (P&I) was below the epidemic threshold.
- One influenza-associated pediatric death was reported and was associated with an influenza A virus for which the subtype was undetermined.
- The proportion of outpatient visits for influenza-like illness (ILI) was 1.8%, which is below the national baseline of 2.3%. Three of 10 regions (Regions 4, 7, and 9) reported ILI at or above region-specific baseline levels.
- No states reported widespread influenza activity. Three states reported regional influenza activity. Puerto Rico and eight states reported local influenza activity. The District of Columbia, Guam and 31 states reported sporadic influenza activity. Eight states reported no influenza activity, and the U.S. Virgin Islands did not report.
WHO and NREVSS collaborating laboratories located in all 50 states and Washington, D.C. report to CDC the number of respiratory specimens tested for influenza and the number positive by influenza type and subtype. The results of tests performed during the current week are summarized in the table below.
During week 11, 7.7% of all deaths reported through the 122-Cities Mortality Reporting System were due to P&I. This percentage was below the epidemic threshold of 7.8% for week 11.
One influenza-associated pediatric death was reported to CDC during week 11 (Mississippi) and was associated with an influenza A virus for which the subtype was undetermined. This death occurred during week 9 (the week ending March 6, 2010).
The influenza activity reported by state and territorial epidemiologists indicates geographic spread of both seasonal influenza and 2009 influenza A (H1N1) viruses and does not measure the severity of influenza activity.