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Influenza Surveillance in Texas
Andrea Salinas, MPH, CPH, CIC
October 23, 2019
Objectives
• List influenza surveillance activities performed in Texas
• Describe current and past flu season trends
• Recognize the strengths and limitations of current surveillance practices
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Influenza Surveillance
• The Influenza Surveillance System is a multi-component surveillance network with local, regional, state, and national activities
• Data collection is based on a reporting week that starts on Sunday and ends on Saturday of each week.
• CDC MMWR Weeks
• October 23 = Week 43
• Flu surveillance season: week 40 to week 20
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Goals of Influenza Surveillance
• Find out when and where influenza activity is occurring
• Determine what type of influenza viruses are circulating
• Detect changes in the influenza virus
• Track influenza-related illness
• Measure the impact influenza is having on deaths
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Texas Influenza Surveillance Activities
• Morbidity
• ILINet: Outpatient ILI
• Outbreaks
• Syndromic
• Mortality
• Influenza-associated pediatric deaths
• Death certificate data
• Viral
• NREVSS: Hospital laboratory reporting
• Public Health Lab testing
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What’s Reportable in Texas?
1.Novel influenza A cases in humans
2.Influenza-associated pediatric deaths
3.Outbreaks (influenza, ILI, etc.)
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Key Term: ILI
• ILI = Influenza-like Illness
• Fever > 100o F, and:
• Cough and/or
• Sore throat
• In the absence of another known cause other than influenza
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Morbidity
ILINet
• US Outpatient ILI Surveillance Network
• Collects aggregate counts of all patients seen and the count of patients with ILI by age group
• Data is reported weekly
• Participation is voluntary2018-2019 influenza season: 114 regularly reporting Texas facilities
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ILINet
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Percentage of Visits Due to ILI Reported by TX ILINet Providers, 2015-2016 to 2018-2019 Seasons
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Morbidity
Outbreaks
• Outbreak reporting is required by lawBoth lab-confirmed influenza and ILI outbreaks
• 183 reported outbreaks in Texas during the 2018-2019 influenza season
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Morbidity
Syndromic Surveillance
• Selected elements of the electronic health record sent to syndromic surveillance system from hospitals, urgent cares, free-standing ERs, etc.
• Symptoms and diagnoses get categorized into “syndromes”
• Data is analyzed for trends and abnormalities
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Mortality
Influenza-associated Pediatric Deaths
• A death in a child under 18 years of age resulting from a clinically compatible illness that was confirmed to be influenza by an appropriate laboratory or rapid diagnostic test
• 2018 – 2019 influenza season statistics• 17 deaths reported• 64.7%* known to be unvaccinated• 35.3% had no known underlying risk
factors
*likely much higher due to 23.5% of cases with unknown vaccination status
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Influenza-associated Pediatric Mortality
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Mortality
Pneumonia & Influenza Mortality
• Data obtained from death certificates
• Underlying or contributing cause(s) of death is reported as pneumonia or influenza
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Age Category (years)
Number of P&I Deaths*
Mortality Rate (per 100,000)
0 - 4 42 1.96
5 - 17 40 0.72
18 - 49 642 4.84
50 - 64 1702 32.81
65 + 7594 198.0
Overall 10020 33.46
HSRNumber of
P&I Deaths*Mortality Rate (per 100,000)
1 369 39.62
2/3 2926 33.77
4/5N 787 48.02
6/5S 2375 30.29
7 1114 30.36
8 1087 35.16
9/10 508 31.76
11 848 33.75
Unknown <10 N/A
Overall 10020 33.46
*NOTE: Data are provisional and subject to
change, errors, and duplicates
Viral Surveillance
NREVSS
• National Respiratory and Enteric Virus Surveillance System
• Healthcare providers voluntarily report total number of respiratory specimens tested and number of positivesData is reported weekly
• Captures influenza test results, along with: Adenovirus, human metapneumovirus, parainfluenza, rhinovirus, enterovirus, RSV, and coronavirus
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Viral Surveillance
Laboratory Surveillance
• Specimens are voluntarily sent to the DSHS lab or Texas LRNs by healthcare providers
• Specimens get tested by PCR Identification and subtyping
• A subset of submitted specimens are sent every two weeks to CDC for further testing
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Laboratory Surveillance
1.Numbered list
a.Second level
i. Third level
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Influenza Surveillance
• Strengths
• Multiple data sources
• Many electronic surveillance systems available
• Weaknesses
• Most reporting is voluntary
• ILI vs Influenza
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Thank youAndrea Salinas, MPH, CPH, CIC
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