# 5326
The CDC’s FluView and an MMWR Influenza Summary report were released yesterday, and after a relatively slow start, the United State’s influenza season is obviously now in full swing with widespread influenza activity being reported across a large swath of the nation.
Particularly hard hit in the latest reporting period are the southern tier of states.
After edging out the H3N2 strain last week for the first time this season, the H1N1 virus has slipped back again to 2nd place, with influenza B bringing up the rear.
A few excerpts from this week’s report. Follow the links to read it in its entirety.
2010-2011 Influenza Season Week 6 ending February 12, 2011
All data are preliminary and may change as more reports are received.
Synopsis:
During week 6 (February 6-12, 2011), influenza activity in the United States remained elevated.
- Of the 9,448 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, 3,306 (35.0%) were positive for influenza.
- The proportion of deaths attributed to pneumonia and influenza (P&I) was above the epidemic threshold.
- Five influenza-associated pediatric deaths were reported. Three of these deaths were associated with 2009 influenza A (H1N1) virus, one was associated with an influenza A virus for which the subtype was not determined, and one was associated with an influenza B virus.
- The proportion of outpatient visits for influenza-like illness (ILI) was 4.5%, which is above the national baseline of 2.5%. All 10 regions reported ILI at or above region-specific baseline levels. Twenty states experienced high ILI activity; nine states experienced moderate ILI activity; New York City and five states experienced low ILI activity, and the District of Columbia and 16 states experienced minimal ILI activity.
- The geographic spread of influenza in 37 states was reported as widespread; 10 states reported regional influenza activity; the District of Columbia reported local activity; Puerto Rico, the U.S. Virgin Islands, and three states reported sporadic influenza activity, and Guam reported no influenza activity.
Pneumonia and Influenza (P&I) Mortality Surveillance
During week 6, 8.9% of all deaths reported through the 122-Cities Mortality Reporting System were due to P&I. This percentage was above the epidemic threshold of 8.0% for week 6.
Influenza-Associated Pediatric Mortality
Five influenza-associated pediatric deaths were reported to CDC during week 6. Three of these deaths were associated with 2009 influenza A (H1N1) virus, one was associated with an influenza A virus for which the subtype was not determined, and one was associated with an influenza B virus. Thirty-five deaths from 20 states (Arizona, Colorado, Florida, Georgia, Illinois, Indiana, Louisiana, Michigan, Nevada, New Jersey, New York, North Carolina, North Dakota, Oklahoma, Pennsylvania, Texas, Utah, Virginia, West Virginia, and Wisconsin) and New York City have been reported during this influenza season.
Thirteen of the 35 deaths reported were associated with influenza B viruses, nine deaths reported were associated with influenza A (H3) viruses, seven were associated with 2009 influenza A (H1N1) viruses, and six were associated with an influenza A virus for which the subtype was not determined.
Outpatient Illness Surveillance:
Nationwide during week 6, 4.5% of patient visits reported through the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet) were due to influenza-like illness (ILI). This percentage is above the national baseline of 2.5%.
The CDC also released a mid-season MMWR update on this year’s flu season, which you can read at the link below.
Update: Influenza Activity --- United States, October 3, 2010--February 5, 2011
Weekly
February 18, 2011 / 60(06);175-181This report summarizes U.S. influenza activity* since the beginning of the 2010--11 influenza season (October 3, 2010) and updates the previous report (1). From October through early December 2010, influenza activity remained low in most regions of the United States.
Activity increased beginning in mid-December 2010 and continued to increase during January and early February 2011. Influenza B, 2009 influenza A (H1N1), and influenza A (H3N2) viruses all have been identified thus far this influenza season, and most viruses in circulation are antigenically similar to strains included in the 2010--11 vaccine.
