2016-2017 Influenza Season Report 2016 Week 40 (October 2 – October 8) through 2017 Week 20 (May 13 – May 20)

Department of Health and Human Services

Divis ion of Publ ic and Behavioral Health

Office of Publ ic Health Informatics and Epidemiology

Brian Sandoval

Governor

State of Nevada

Richard Whitely, MS

Director

Department of Health and Human Services

Cody L. Phinney, MPH

Administrator

Division of Public and Behavioral Health

John DiMuro, D.O., MBA

Chief Medical Officer

Division of Public and Behavioral Health

August 2017

Edition 1.0

2016-2017 Influenza Season Report v 2017 i 21 (October 2, 2016 – May 20, 2017)

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Data for the graphs and tables on the following pages are provisional and may be updated as additional information becomes available.

Purpose

The purpose of this report is to provide an overview of and statistics for the 2016-2017 influenza season in Nevada for the local public health

authorities, sentinel providers and the public.

Influenza-Like Illness Network Surveillance (ILINet)

Respiratory specimens are tested for influenza by the World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance

System (NRVESS) collaborating laboratories by sub-type. During the influenza season, there were 940,791 specimens collected nationally and tested

for influenza, of those 161,094 were positive with influenza (17.1%). The season peak was week 7 with 28% positive for influenza.

Figure 1

Source of Data: CDC: FluView Weekly Report.

The Nevada total includes laboratory tests for all Nevada residents including out of state laboratories. During the 2016-2017 season 1,072

specimens were tested for influenza, of which 410 were positive (38.2%). Nevada’s peak for positives test was week 1 (57.1%).

Figure 2

Source of Data: CDC: ILINet.

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National Influenza Positive Tests by Week2016 WK 40 - 2017 WK 20

2009H1N1 A(H3) A(Unknown Subtyping) B (Victoria Lineage)B (Yamagata Lineage) B(Unknown Subtyping) Percent Positive

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Nevada (ILI Providers) Influenza Laboratory Confirmed Positive by Week2016 WK 40 - 2017 WK 20

2009H1N1 A(H3) A(Subtyping not performed) B (Victoria Lineage) B (Yamagata Lineage) B(Unknown Subtyping)

2016-2017 Influenza Season Report v 2017 i 21 (October 2, 2016 – May 20, 2017)

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Nevada State Public Health Laboratory (NSPHL) tested 353 specimens for influenza from sentinel providers, of which 299 were positive

(84.7%). Southern Nevada Public Health Laboratory (SNPHL) tested 75 specimens this season of which 7 were positive (9.3%). The national

numbers in Table 1 are reflected in Figure 1. The state of Nevada data in Table 1 is reflected in Figure 2. The Nevada total includes laboratory

test for all Nevada residents including out of state laboratories.

Table 1

ILINet Surveillance: Influenza Specimens Tested State and Nationally

NSPHL SNPHL State of Nevada National

# % # %

Specimens Tested 353 75 1,072 940,791

Positives to Influenza 299 7 410 38.2 161,094 17.1

Influenza A: 264 5 355 86.6 116,362 72.2

A(2009 H1N1) 11 0 12 3.4 886 0.8

A(H3) 253 5 266 74.9 30,391 26.1

A(Sub-typing not performed) 0 0 77 21.7 85,085 73.1

Influenza B: 35 2 55 13.4 44,732 27.8

Source of Data: CDC: FluView Report and CDC: ILINet.

Influenza-like Illness (ILI) Surveillance Network has each sentinel providers report the number of patients that meet the ILI case definition and

number of patients that visit the provider weekly. The “percentage of visits” is the number of ILI patients divided by the total number of patients

visit per week. Nevada’s ILI percentage peaked during week 52 at 2.12%. Nevada remained at or above the state baseline for 10 weeks, weeks

49 – 6. Region 9 ILI percentage peaked during week 52 at 3.3%, and remained above the regional baseline for 10 weeks, weeks 51-8. Region 9

includes the following states/territory: Arizona, California, Guam, Hawaii, and Nevada. The national ILI percentage peaked during week 6 at

5.1%, and remained above the national baseline for 17 weeks (weeks 50-14).

Figure 3

Source of Data: CDC: Flu View Report and CDC: ILINet.

The percentage of visits for ILI peaked at week 52 for the 2016-2017 season whereas in the previous season (2015-2016) the peak occurred

during week 9.

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Percentage of Visits for ILI Reported to Outpatient ILI Surveillance Network,Comparison Between National, Regional, and State,

2016 WK 40 - 2017 WK 20

Nevada Region 9 National Nevada Baseline

2016-2017 Influenza Season Report v 2017 i 21 (October 2, 2016 – May 20, 2017)

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Figure 4

Source of Data: CDC: ILINet.

Influenza-like Illness is reported by age groups, during the 2016-2017 season the 0-4 age group had the highest amount of patients seen with ILI. The

highest number of patients were seen during week 52 at a rate of 13.4 per 100,000 population. The rate is calculated by the number of patients

presented with ILI, divided by the state population, multiplied by 100,000. The estimated state population for 2017 is 2,935,490.

Figure 5

Source of Data: CDC: ILINet.

Influenza Positive Surveillance (NBS and NETSS)

Laboratory confirmed cases of influenza are reported to the state health authority for surveillance purposes. Table 2 and Figure 6 reflect all positive

influenza cases reported to the state. Types of influenza testing include commercial rapid diagnostic test (rapid), viral culture, fluorescent antibody,

enzyme immunoassay, RT-PCR (PCR), and Immunohistochemistry. The two most common test types in Nevada are Rapid and PCR tests. During

2016-2017 season, there were 8,578 positive influenza cases reported to the state, 6,819 influenza A cases, 1,336 influenza B cases and 423 unknown

subtyping.

Table 2

Reporting Jurisdiction

Reported Influenza Cases by County Jurisdiction and Influenza Type

Influenza Season

A B Unknown Total

Carson City Health and Human Services 831 141 3 975

Rural Community Health Services 581 68 37 687

Southern Nevada Health District 3,404 899 228 4,603

Washoe County Health District 1,994 228 155 1,781

State of Nevada 6,819 1,336 423 8,578

Source: OPHIE: NBS and SNHD: NETSS.

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Nevada Percentage of Visits for Influenza-like Illness, Weekly Summary2016 WK 40 - 2017 WK 20

2016 WK 40 - 2017 WK 20 2015 WK 18 - 2016 WK 18 2014 WK 18 - 2015 WK 18

2013 WK 18 - 2014 WK 18 2012 WK 18 - 2011 WK 18 Baseline

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ILINet: Influenza-like Illness by Age Group and MMWR Week and Incidence Rate 2016 WK 40 - 2017 WK 20

0-4 5-24 25-49 50-64 65+ Rate

2016-2017 Influenza Season Report v 2017 i 21 (October 2, 2016 – May 20, 2017)

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Figure 6

Source of Data: OPHIE: NBS and SNHD: NETSS.

Hospitalizations

There were a total of 535 hospitalizations associated with influenza reported to the state health authority during the 2016-2017 season.

Table 3

Influenza Hospitalizations

Reporting Jurisdiction Influenza Season

# %

Carson City Health and Human Services 36 6.7 Rural Community Health Services 20 3.8

Southern Nevada Health District 181 33.8 Washoe County Health District 298 55.7

State of Nevada 535 100 Source: Reported to Office of Public Health Informatics and Epidemiology from each Jurisdiction.

Pneumonia and Influenza (P&I) Mortality Surveillance

The Pneumonia and Influenza (P&I) mortality percentage is the deaths, where Pneumonia or Influenza is listed as the underlying or contributing

cause of death, divided by the total deaths in Nevada for each week. The peak of P&I mortality was week 52, there were 42 P&I deaths out of 403

total deaths (10.4%). The CDC’s most up-to-date National Epidemic Threshold data was for week 18.

Figure 7

Source: OVR: WEVRRS and CDC: FluView.

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Weekly Reported Influenza by Subtype as Compared with Respiratory Syncytial Virus Infections (RSV) 2016 WK 40 - 2017 WK 20

RSV Influenza A Influenza B

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Pneumonia and Influenza (P&I) Mortality by Week,NCHS Mortality Surveillance Data Compared to Nevada

2016 WK 40 - 2017 WK 20

Nevada National National Epidemic Threshold

2016-2017 Influenza Season Report v 2017 i 21 (October 2, 2016 – May 20, 2017)

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Technical Notes Influenza-like illness (ILI): a fever greater than or equal 100℉ with cough and/or sore throat

Percent positive: The number of positive influenza laboratory tests divided by the total number of tests performed.

Incidence rate is per 100,000 population as estimated by the state demographer.

This report contains information from national and state-level data sources. Influenza surveillance data is collected by a various systems,

including:

Influenza-like Illness Network (ILINet): a sentinel surveillance system in collaboration with the Centers for the Disease Control and

Prevention (CDC) where outpatient providers report ILI information weekly.

National Electronic Telecommunication System for Surveillance (NETSS): a system whereby data is transmits to CDC. Influenza

data collected through NETSS does not provide influenza sub-typing information.

National Electronic Disease Surveillance System (NEDSS): a system for collecting data and monitoring disease trends and

outbreaks.

NEDSS Based System (NBS): an implementation of the NEDSS standards. It provides a secure, accurate, and efficient means of

collecting, transmitting, and analyzing public health data.

Citations

1. CDC. FluView: A Weekly Influenza Surveillance Report. http://www.cdc.gov/flu/weekly/pastreports.htm.

2. Nevada State Demographer’s Office. 2003-2014 ASRHO Estimates and Projections. Division of Public and Behavioral Health edition.

Vintage 2016.

3. OPHIE. DPBH. NBS. 2013-2014. Accessed May 2017.

4. Office of Vital Records (OVR). DPBH. Web Enabled Vital Records Registry System (WEVRRS) [unpublished data]. 2016-2017. Accessed

May 2017.

5. Southern Nevada Health District (SNHD). NETSS/Trisano. 2016-2017. Accessed May 2017.

Comments, suggestions, and requests for further information may be addressed to:

NEVADA INFLUENZA SURVEILLANCE PROGRAM

OFFICE OF PUBLIC HEALTH INFORMATICS AND EPIDEMIOLOGY

500 DAMONTE RANCH PARKWAY, STE 657

RENO NV 89521

TEL: (775) 684-5289

FAX: (775) 684-5999

Compiled and Written by:

LILIANA E. WILBERT, MPH

Recommended Citation:

Division of Public and Behavioral Health. Office of Public Health Informatics and Epidemiology. Influenza Weekly Report, 2016 Week 40 (October 02)

through 2017 Week 20 (May 20), Nevada. August 2017 i 21 edition 1.0.

This publication was supported by Cooperative Agreement Number TP000534-02 from the

Centers for Disease Control and Prevention and/or Assistant Secretary for Preparedness and

Response. Its contents are solely the responsibility of the authors and do not necessarily

represent the official views of the Centers for Disease Control and Prevention and/or Assistant

Secretary for Preparedness and Response.