2011-2012 Influenza Season Week 1 ending January 7, 2012

All data are preliminary and may change as more reports are received.

Synopsis:

During week 1 (January 1-7, 2012), influenza activity increased in the United States, but remains relatively low.

U.S. Virologic Surveillance: Of the 3,199 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, 108 (3.4%) 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: No influenza-associated pediatric deaths were reported.
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. Two states experienced low ILI activity, New York City and 48 states experienced minimal ILI activity, and the District of Columbia had insufficient data.
Geographic Spread of Influenza: The geographic spread of influenza in two states was reported as regional; seven states reported local activity; 37 states reported sporadic activity; the District of Columbia, Guam, the U.S. Virgin Islands and four states reported no influenza activity, and Puerto Rico did not report.

National and Regional Summary of Select Surveillance Components
HHS Surveillance Regions*	Data for current week			Data cumulative since October 2, 2011 (Week 40)
HHS Surveillance Regions*	Out-patient ILI†	% of respiratory specimens positive for flu‡	Number of jurisdictions reporting regional or widespread activity§	A (H3)	2009 H1N1	A(Subtyping not performed)	B	Pediatric Deaths
Nation	Normal	3.4%	2 of 54	464	30	367	188	0
Region 1	Normal	2.2%	1 of 6	14	1	0	7	0
Region 2	Normal	0.5%	0 of 4	7	1	4	2	0
Region 3	Normal	0.7%	0 of 6	13	1	4	0	0
Region 4	Normal	3.7%	0 of 8	46	10	176	116	0
Region 5	Normal	9.0%	0 of 6	85	7	6	11	0
Region 6	Normal	1.1%	0 of 5	14	1	23	18	0
Region 7	Normal	4.9%	0 of 4	46	0	22	2	0
Region 8	Normal	7.9%	1 of 6	140	1	77	9	0
Region 9	Normal	5.4%	0 of 5	65	7	50	17	0
Region 10	Normal	2.6%	0 of 4	34	1	5	6	0

*HHS regions (Region 1 CT, ME, MA, NH, RI, VT; Region 2: NJ, NY, Puerto Rico, US Virgin Islands; Region 3: DE, DC, MD, PA, VA, WV; Region 4: AL, FL, GA, KY, MS, NC, SC, TN; Region 5: IL, IN, MI, MN, OH, WI; Region 6: AR, LA, NM, OK, TX; Region 7: IA, KS, MO, NE; Region 8: CO, MT, ND, SD, UT, WY; Region 9: AZ, CA, Guam, HI, NV; and Region 10: AK, ID, OR, WA).
† 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

U.S. Virologic Surveillance:

WHO and NREVSS collaborating laboratories located in all 50 states 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.

	Week 1
No. of specimens tested	3,199
No. of positive specimens (%)	108 (3.4%)
Positive specimens by type/subtype
Influenza A	102 (94.4%)
2009 H1N1	5 (4.9%)
Subtyping not performed	42 (41.2%)
(H3)	55 (53.9%)
Influenza B	6 (5.6%)