Weekly U.S. Influenza Surveillance Report

CDC's Influenza Division produces a weekly influenza surveillance report, FluView. According to this week's report (Dec 10-Dec 16), seasonal influenza activity increased sharply in the United States. Ten states (AL, AR, AK, KY, LA, MS, NV, OK, SC & TX) experienced high Influenza Like Illness (ILI) activity levels. Puerto Rico and eight states (CA, GA, IL, KS, MI, NE, OR, WV) experienced moderate ILI activity.

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Synopsis:

During week 50 (December 10-16, 2017), influenza activity sharply increased in the United States.

Viral Surveillance: The most frequently identified influenza virus subtype reported by public health laboratories during week 50 was influenza A(H3). The percentage of respiratory specimens testing positive for influenza in clinical laboratories increased.
Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below the system-specific epidemic threshold in the National Center for Health Statistics (NCHS) Mortality Surveillance System.
Influenza-associated Pediatric Deaths: One influenza-associated pediatric death was reported.
Influenza-associated Hospitalizations: A cumulative rate of 6.2 laboratory-confirmed influenza-associated hospitalizations per 100,000 population was reported.
Outpatient Illness Surveillance:The proportion of outpatient visits for influenza-like illness (ILI) was 3.5%, which is above the national baseline of 2.2%. Nine of the 10 regions reported ILI at or above region-specific baseline levels. Ten states experienced high ILI activity; Puerto Rico and eight states experienced moderate ILI activity; New York City, the District of Columbia, and 11 states experienced low ILI activity; and 21 states experienced minimal ILI activity.
Geographic Spread of Influenza:The geographic spread of influenza in 23 states was reported as widespread; Puerto Rico and 23 states reported regional activity; the District of Columbia and four states reported local activity; the U.S. Virgin Islands reported sporadic activity; and Guam did not report.