# 4168
The CDC has posted FluView for week 49, ending December 12th , 2009. The amount of flu activity we are seeing has decreased again for the seventh straight week after four consecutive weeks of sharp gains, but is still slightly higher than normally seen this time of year.
P&I (pneumonia & Influenza) deaths decreased over the last week but remain above the epidemic level for the eleventh week in a row, and 9 pediatric influenza-related deaths were added last week.
While the numbers here in the US, and also in Canada, reflect a winding down of the fall pandemic wave, what lies ahead is less clear. There are more than 4 more months remaining in flu season, and there are a number of possible scenarios (see Waiting For The Other Flu To Drop).
We’ll just have to wait to see. In the meantime, we’ll take any respite we can get. It should be noted that of the samples submitted for analysis, just under 7% tested positive for influenza.
Which means there are apparently a lot of flu-like illnesses in circulation right now, and having had one doesn’t guarantee you’ve developed immunity to the H1N1 virus.
I’ve excerpted some of the data and graphs below, but follow the link to read it in its entirety.
2009-2010 Influenza Season Week 49 ending December 12, 2009
All data are preliminary and may change as more reports are received.
Synopsis:
During week 49 (December 6-12, 2009), influenza activity continued to decrease in the U.S.
- 391 (6.9%) 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.
- Over 99% of all subtyped influenza A viruses being reported to CDC were 2009 influenza A (H1N1) viruses.
- The proportion of deaths attributed to pneumonia and influenza (P&I) was above the epidemic threshold for the eleventh consecutive week.
- Nine influenza-associated pediatric deaths were reported. Eight of these deaths were associated with 2009 influenza A (H1N1) virus infection and one was associated with an influenza A virus for which the subtype was undetermined.
- The proportion of outpatient visits for influenza-like illness (ILI) was 2.6% which is above the national baseline of 2.3%. Five of the 10 regions reported ILI at or above region-specific baseline levels. Regions 3, 6, 7, 8 and 10 reported ILI below their region specific baselines.
- Eleven states reported geographically widespread influenza activity, 20 states reported regional influenza activity, the District of Columbia, Puerto Rico, and 11 states reported local influenza activity, the U.S. Virgin Islands and eight states reported sporadic influenza activity, and Guam reported no influenza activity.
U.S. Virologic Surveillance:
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.
Pneumonia and Influenza (P&I) Mortality Surveillance
During week 49, 7.6% of all deaths reported through the 122-Cities Mortality Reporting System were due to P&I. This percentage was above the epidemic threshold of 7.2% for week 49. Including week 49, P&I mortality has been above threshold for 11 consecutive weeks.
Influenza-Associated Pediatric Mortality
Nine influenza-associated pediatric deaths were reported to CDC during week 49 (California [3], Florida, Kentucky, Massachusetts, North Carolina, Oklahoma, and Texas). Eight of these deaths were associated with 2009 influenza A (H1N1) virus infection and one was associated with an influenza A virus for which the subtype is undetermined. The deaths reported during week 49 occurred between August 23 and December 5, 2009.
One death associated with 2009 influenza A (H1N1) virus infection reported during week 49 occurred in August during the 2008-09 season, bringing the total number of reported pediatric deaths occurring during that season to 130.
