INFLUENZA SURVEILLANCE
Julie L Freshwater, MPH PhD
Influenza Surveillance Coordinator
Objectives2
Define public health surveillance List the importance and uses of
surveillance data Identify data quality issues Discussion to identify strategies to
improve data and data quality issues
“Ongoing, systematic collection, analysis, interpretation, and dissemination of data regarding a health-related event for use in public health action to reduce morbidity and mortality and to improve health”Centers for disease control and prevention, 2001
PUBLIC HEALTH SURVEILLANCE3
Components of West Virginia’s Influenza Surveillance System
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Local Health Department (LHD) Schools Providers
ILINet Providers (ILINet) Sentinel Providers
Laboratories (Labs) Sentinel Hospital Commercial Office of Laboratory Services (OLS)
Local HealthDepartments (LHD)
Sentinel Providers(ILINet)
Office of Laboratory Services (OLS)
Hospital/referral laboratories
DIDE
CDC
Influenza-like Illness (ILI)
Laboratory Data
Feedback to Stakeholders
Influenza Surveillance in West Virginia
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System Objectives6
Identify earliest case of influenza A in the state
Estimate duration of season Identify outbreaks Determine if circulating types of
influenza are vaccine-strain
Surveillance Data Use7
Inform the stakeholders by
Graphs
Maps
Newsletters
Influenza Data Use8
Healthcare providers and hospitals Public health departments General public CDC WHO FDA Vaccine manufacturers
SURVEILLANCE FOR INFECTIOUS DISEASES
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Surveillance method Flexible Sensitive
Surveillance data Representative Timely Accurate and complete
THREATS TO DATA QUALITY10
1. Lack of representativeness
2. Under-reporting
3. Inconsistent case definitions
4. Poor data quality
5. Lack of timeliness
1. LACK OF REPRESENTATIVENESS
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Data does not reflect the entire population under surveillance
Representativeness of West Virginia Influenza Surveillance Data 201012
Local health departments’ data 5 smallest counties data from 90% of
providers 5 largest counties data from 29% of providers
ILINet 61% from rural 36% from small town
Provider Demographics13
Family practice (61%) Emergency Department (16%); Urgent Care (8%) Internal Medicine and Pediatrician (5%
ea) Student Health (3%) Infectious Diseases and Health
Department (1% ea)
Improving Representativeness of ILINet Data in your region
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Population of your county?
Demographics? ILINet providers see a representative
sample of the population?
How would you improve
representativeness?
Improving Representativeness of LHD ILI Data in your region
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The state now has access to school absentee data, is there another source of data that could be collected at the local level?
Can the method of data collection be improved?
2. UNDERREPORTING16
Lack of awareness to report
Negative attitude toward reporting
Misconceptions that arise from lack of
knowledge or negative attitude
Improving Reporting of West Virginia Influenza Surveillance Data 201017
Provide frequent feedback
Could lack of knowledge of how data is used be a barrier?
How do you communicate with your providers?
3. INCONSISTENT DEFINITIONS
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Providers may use clinical criteria that differs from the public health case definition
Case definition may change over time and not all reporters use most current version
Case Definition Use in West Virginia Influenza Surveillance Data 201019
ILINet Providers 53% use CDC case definition exclusively
Some use multiple case definitions
Improving Case Definition Use for ILINet West Virginia Surveillance Data20
Does your sentinel provider use the CDC case definition exclusively to report ILI?
What strategies have been used in your region to improve the use of the ILI case definition?
What recommendations do you have to improve the use of the ILI case definition by sentinel providers?
4. POOR DATA QUALITY21
Incorrect information
Missing data elements
Duplicate records
Inconsistent information
Across geographic areas
Across reporters
Improving Data Quality for West Virginia Influenza Surveillance Data22
Is the data complete to ILINet? Does the sentinel provider send 2
specimens a week to OLS for testing?
5. LACK OF TIMELINESS23
Disease dependent reasons
Procedure dependent reasons
Time of report submission/processing
Delay in surveillance analysis
Delay in dissemination
Timeliness of influenza reporting January through May 2011 in West Virginia24
LHD <2 weeks of missing data :36 Reported late <2 times: 34
ILINet <2 weeks of missing data :12 Reported late <2 times: 17
Improving Timeliness for West Virginia Influenza Surveillance Data25
Issues with timeliness of reporting by sentinel providers?
Issues with timeliness of reporting by your LHD?
Any strategies to improve timeliness?
Recommendations for improving timeliness?
Specimens26
Isolates provide specific information
Compare
Guide
Formulate
Monitor
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“A robust sentinel provider system is
one of the best and most efficient means
to staying prepared for novel and
seasonal influenza because the
combination of surveillance for ILI and
laboratory confirmation carries
preparedness to the local level. We
recognize this may not be feasible in
some of the smallest counties, however
the track record of success for many
counties is readily apparent from the
data.”
For Discussion28
List of questions
ILINet reporting data
LHD reporting data
Specimen submissions to OLS
County population data
Thanks to29
Dr. Dee Bixler Dr. Tegwin Taylor UNC Center for Public Health Preparedness Local Health Departments Sentinel providers and those in the office
that compile and report the data Laboratories OLS Grant from the CDC
QUESTIONS?
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