2011-2012 Influenza Season Week 47 ending November 26, 2011
- U.S. Virologic Surveillance: Of the 2,130 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, 40 (1.9%) were positive for influenza..
- Pneumonia and Influenza (P&I) Mortality Surveillance: The proportion of deaths attributed to P&I was below the epidemic threshold.
- Influenza-associated Pediatric Mortality: Two influenza-associated pediatric deaths were reported. These deaths occurred during the 2010-11 influenza season.
- Outpatient Illness Surveillance: The proportion of outpatient visits for influenza-like illness (ILI) was 1.4%, which is below the national baseline of 2.4%. All 10 regions reported ILI below region-specific baseline levels. All 50 states and New York City experienced minimal ILI activity and the District of Columbia had insufficient data.
- Geographic Spread of Influenza: The geographic spread of influenza in one state was reported as local; the District of Columbia, Guam, and 29 states reported sporadic activity; the U.S. Virgin Islands and 21 states reported no influenza activity, and Puerto Rico did not report.
|HHS Surveillance Regions*||Data for current week||Data cumulative since October 2, 2011 (Week 40)|
|Out-patient ILI†||% of respiratory specimens positive for flu‡||Number of jurisdictions reporting regional or widespread activity§||A (H3)||2009 A (H1N1)||A(Subtyping not performed)||B||Pediatric Deaths|
|Nation||Normal||1.9%||0 of 54||79||8||104||75||0|
|Region 1||Normal||0.0%||0 of 6||1||0||0||3||0|
|Region 2||Normal||0.4%||0 of 4||2||0||2||1||0|
|Region 3||Normal||0.3%||0 of 6||2||0||3||0||0|
|Region 4||Normal||3.4%||0 of 8||8||1||74||48||0|
|Region 5||Normal||1.5%||0 of 6||10||2||1||6||0|
|Region 6||Normal||0.3%||0 of 5||4||0||2||8||0|
|Region 7||Normal||0.9%||0 of 4||6||0||3||1||0|
|Region 8||Normal||2.3%||0 of 6||20||1||11||0||0|
|Region 9||Normal||0.5%||0 of 5||18||4||4||6||0|
|Region 10||Normal||0.7%||0 of 4||8||0||4||2||0|
† Elevated means the % of visits for ILI is at or above the national or region-specific baseline
‡ National data are for current week; regional data are for the most recent three weeks
§ Includes all 50 states, the District of Columbia, Guam, Puerto Rico, and U.S. Virgin Islands
|No. of specimens tested||2,130|
|No. of positive specimens (%)||40 (1.9%)|
|Positive specimens by type/subtype|
|Influenza A||33 (82.5%)|
|A (2009 H1N1)||1 (3.0%)|
|A (subtyping not performed)||26 (78.8%)|
|A (H3)||6 (18.2%)|
|Influenza B||7 (17.5%)|
- One virus was characterized as A/California/7/2009-like, the influenza A (H1N1) component of the 2011-12 influenza vaccine for the Northern Hemisphere.
- All 16 were characterized as A/Perth/16/2009-like, the influenza A (H3N2) component of the 2011-12 influenza vaccine for the Northern Hemisphere.
- Victoria Lineage : Three of four B viruses tested belong to the B/Victoria lineage of viruses and were characterized as B/Brisbane/60/2008-like, the recommended influenza B component for the 2011-12 Northern Hemisphere influenza vaccine.
- Yamagata Lineage : One of four B viruses tested belongs to the B/Yamagata lineage of viruses.
|Virus Samples tested (n)||Resistant Viruses, Number (%)||Virus Samples tested (n)||Resistant Viruses, Number (%)|
|Influenza A (H3N2)||24||0 (0.0)||24||0 (0.0)|
|Influenza B||2||0 (0.0)||2||0 (0.0)|
|Influenza A (2009 H1N1)||5||0 (0.0)||5||0 (0.0)|
ILINet State Activity Indicator Map:
- All 50 states and New York City experienced minimal ILI activity (Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming).
- Data were insufficient to calculate an ILI activity level from the District of Columbia.
Data collected in ILINet may disproportionately represent certain populations within a state, and therefore, may not accurately depict the full picture of influenza activity for the whole state.
Data displayed in this map are based on data collected in ILINet, whereas the State and Territorial flu activity map are based on reports from state and territorial epidemiologists. The data presented in this map is preliminary and may change as more data is received.
Differences in the data presented here by CDC and independently by some state health departments likely represent differing levels of data completeness with data presented by the state likely being the more complete.
- Local influenza activity was reported by one state (Massachusetts).
- Sporadic influenza activity was reported by the District of Columbia, Guam, and 29 states (Alaska, Arkansas, California, Colorado, Connecticut, Florida, Hawaii, Illinois, Indiana, Iowa, Kentucky, Louisiana, Minnesota, Mississippi, Nebraska, Nevada, New Mexico, New York, North Dakota, Ohio, Pennsylvania, Rhode Island, South Carolina, Texas, Utah, Washington, West Virginia, and Wisconsin).
- No influenza activity was reported by the U.S. Virgin Islands and 21 states (Alabama, Arizona, Delaware, Georgia, Idaho, Kansas, Maine, Maryland, Michigan, Missouri, Montana, New Hampshire, New Jersey, North Carolina, Oklahoma, Oregon, South Dakota, Tennessee, Vermont, Virginia, and Wyoming).
- Puerto Rico did not report.
Additional National and International Influenza Surveillance Information