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#Assessment of #risk associated with #influenza A(#H5N8) virus, 17 November 2016 (@WHO)

  Title : #Assessment of #risk associated with #influenza A(#H5N8) virus, 17 November 2016. Subject : Avian Influenza, H5N8 subtype, multi...

28 Nov 2016

Weekly #US #Influenza #Surveillance #Report - 2016-2017 Season, Wk 46 ending Nov. 19, 2016 (@CDCgov, Nov. 28 ‘16)

 

Title: Weekly #US #Influenza #Surveillance #Report - 2016-2017 Season, Wk 46 ending Nov. 19, 2016.

Subject: Seasonal Influenza, weekly US CDC epidemiological update.

Source: US Centers for Disease Control and Prevention (CDC), FluView, full page: (LINK). Extracts, edited.

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Weekly U.S. Influenza Surveillance Report - 2016-2017 Influenza Season Week 46 ending November 19, 2016

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|-- Full report also available as PDF –|

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

 

Synopsis:

  • During week 46 (November 13-19, 2016), influenza activity increased slightly, but remained low in the United States.
    • Viral Surveillance:
      • The most frequently identified influenza virus subtype reported by public health laboratories during week 46 was influenza A (H3).
      • The percentage of respiratory specimens testing positive for influenza in clinical laboratories increased slightly, but remained low.
    • Novel Influenza A Virus:
      • One human infection with a novel influenza A virus was reported.
    • 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:
      • No influenza-associated pediatric deaths were reported.
    • Outpatient Illness Surveillance:
      • The proportion of outpatient visits for influenza-like illness (ILI) was 1.6%, which is below the national baseline of 2.2%.
      • Two regions reported ILI at or above their region-specific baseline levels.
      • Puerto Rico experienced high ILI activity, 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 Guam, Puerto Rico, and the U.S. Virgin Islands was reported as regional; 11 states reported local activity; the District of Columbia and 36 states reported sporadic activity; and three states reported no activity.

 

National and Regional Summary of Select Surveillance Components

[HHS Surveillance Regions* - Data for current week: Out-patient ILI† - Number of jurisdictions reporting regional or widespread activity§ - % respiratory specimens positive for flu in clinical laboratories‡  - Data cumulative since October 2, 2016 (week 40): A(H1N1)pdm09 - A (H3) - A (Subtyping not Performed) - B Victoria lineage - B Yamagata lineage - B lineage not performed - Pediatric Deaths]

Influenza test results from public health laboratories only

  • Nation – Normal - 3 of 54 - 2.7% – 59 – 569 – 33 – 26 – 18 – 26 – 0
    • Region 1 – Normal - 0 of 6 - 0.9% – 0 – 27 – 0 – 0 – 0 – 0 – 0
    • Region 2 – Elevated - 2 of 4 - 1.0% – 0 – 41 – 2 – 8 – 4 – 2 – 0
    • Region 3 – Normal -  0 of 6 - 0.4% – 5 – 30 – 0 – 1 – 1 – 1 – 0
    • Region 4 – Elevated - 0 of 8 - 4.1% – 3 – 49 – 3 – 3 – 2 – 13 – 0
    • Region 5 – Normal - 0 of 6 - 0.8% – 2 – 56 – 19 – 4 – 1 – 3 – 0
    • Region 6 – Normal - 0 of 5 - 1.5% – 7 – 11 – 0 – 5 – 5 – 0 – 0
    • Region 7 – Normal - 0 of 4 - 0.3% – 0 – 11 – 1 – 2 – 0 – 0 – 0
    • Region 8 – Normal - 0 of 6 - 1.8% – 26 – 63 – 1 – 0 – 0 – 0 – 0
    • Region 9 – Normal - 1 of 4 - 1.6% – 15 – 177 – 7 – 1 – 5 – 4 – 0
    • Region 10 – Normal - 0 of 4 - 7.4% – 1 – 104 – 0 – 2 – 0 – 3 – 0

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{*} 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

{§} Includes all 50 states, the District of Columbia, Guam, Puerto Rico, and U.S. Virgin Islands

{‡} National data are for current week; regional data are for the most recent three weeks

 

U.S. Virologic Surveillance

WHO and NREVSS collaborating laboratories, which include both public health and clinical laboratories located in all 50 states, Puerto Rico, and the District of Columbia, report to CDC the total number of respiratory specimens tested for influenza and the number positive for influenza by virus type. In addition, public health laboratories also report the influenza A subtype (H1 or H3) and influenza B lineage information for the viruses they test and the age or age group of the persons from whom the specimens were collected.

Additional data are available at http://gis.cdc.gov/grasp/fluview/fluportaldashboard.html and http://gis.cdc.gov/grasp/fluview/flu_by_age_virus.html.

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The results of tests performed by clinical laboratories during the current week are summarized below.

[Week 46 - Data Cumulative since October 2, 2016 (Week 40)]

  • No. of specimens tested - 14,030 - 98,040
    • No. of positive specimens (%) - 385 (2.7%) - 1,731 (1.8%)
      • Positive specimens by type:
        • Influenza A - 273 (70.9%) - 1,121 (64.8%)
        • Influenza B - 112 (29.1%) - 610 (35.2%)

(…)

View National and Regional Level Graphs and Data

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The results of tests performed by public health laboratories, as well as the age group distribution of influenza positive tests, during the current week are summarized below.

[Week 46 - Data Cumulative since October 2, 2016 (Week 40)]

  • No. of specimens tested – 651 - 6,716
    • No. of positive specimens* – 75 – 731
      • Positive specimens by type/subtype:
        • Influenza A - 73 (97.3%) - 661 (90.4%)
          • A(H1N1)pmd09 - 3 (4.1%) - 59 (8.9%)
          • H3 - 57 (78.1%) - 569 (86.1%)
          • Subtyping not performed - 13 (17.8%) - 33 (5.0%)
        • Influenza B - 2 (2.7%) - 70 (9.6%)
          • Yamagata lineage - 0 (0%) - 18 (25.7%)
          • Victoria lineage - 0 (0%) - 26 (37.1%)
          • Lineage not performed   2 (100%) - 26 (37.1%)

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{*} The percent of specimens testing positive for influenza is not reported because public health laboratories often receive samples that have already tested positive for influenza at a clinical laboratory and therefore percent positive would not be a valid indicator of influenza activity. Additional information is available at http://www.cdc.gov/flu/weekly/overview.htm.

(…)

View National and Regional Level Graphs and Data

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Antigenic Characterization

During May 22 – November 19, 2016, CDC has antigenically characterized 203 influenza viruses [21 influenza A (H1N1)pdm09, 99 influenza A (H3N2), and 83 influenza B viruses] collected by U.S. laboratories.

  • Influenza A Virus [120]
    • A (H1N1)pdm09 [21]:
      • All 21 (100%) influenza A (H1N1)pdm09 viruses were antigenically characterized using ferret post-infection antisera as A/California/7/2009-like, the influenza A (H1N1) component of the 2016-2017 Northern Hemisphere vaccine.
    • A (H3N2) [99]:
      • 85 (85.9%) of 99 influenza A (H3N2) viruses were antigenically characterized as A/Hong Kong/4801/2014-like, a virus that belongs in genetic group 3C.2a and is the influenza A (H3N2) component of the 2016-2017 Northern Hemisphere vaccine, by HI testing or neutralization testing.
      • Among the viruses which reacted poorly with ferret antisera raised against A/Hong Kong/4801/2014-like viruses, 13 of 14 (92.9%) are more closely related to A/Switzerland/9715293/2013, a virus belonging to genetic group 3C.3a.
  • Influenza B Virus [83]
    • Victoria Lineage [36]:
      • All 36 (100%) B/Victoria-lineage viruses were antigenically characterized using ferret post-infection antisera as B/Brisbane/60/2008-like, which is included as an influenza B component of the 2016-2017 Northern Hemisphere trivalent and quadrivalent influenza vaccines.
    • Yamagata Lineage [47]:
      • All 47 (100%) B/Yamagata-lineage viruses were antigenically characterized using ferret post-infection antisera as B/Phuket/3073/2013-like, which is included as an influenza B component of the 2016-2017 Northern Hemisphere quadrivalent influenza vaccines.

(…)

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Keywords: US CDC; USA; Updates; Seasonal Influenza.

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