Event based
surveillance systems
Alicia Barrasa
EPIET Introductory course 2011
Lazareto, Menorca, Spain
Infectious diseases
Arise from many different pathogens: viruses, bacteria,
parasites
Spread in many different species: humans, insects,
domestic and wild animals, aquatic animals and
sometimes breach barrier between animal and humans
(70% of emerging infections arise from animal
population)
Take many different routes of transmission: direct
contact, vectors, food, environmental
Affect all populations in all regions of the world
Emerging and Re-emerging
infectious diseases
Legionnaire’s disease
Cryptosporidiosis
Shigellosis
Human monkepox
West
Nile
Virus
E. coli O157
BSE
nvCJD
Multidrug resistant Salmonella
E.coli non-O157
Malaria Typhoid
E. coli O157
Rabies
SARS
Diphtheria
West
Nile
Fever
Reston
Typhoid
Influenza A (H5N1)
Kyasanur f.
Lassa fever
Echinococcosis
Nipah Virus
Yellow fever
Cholera O139
RVF/VHF
Reston Virus
Venezuelan
Buruli ulcer
Dengue
equine encephalitis
O’nyong-nyong haemhorrhagic Respiratory
Ebola
fever
fever
infection
haemorrhagic
Dengue
Human
haemhorrhagic feverCholera fever
Ross
monkeypox
Hendra
River
virus
Cholera
virus
Shigellosis
Lyme Borreliosis
Epidemic Alert and Response (EAR), WHO Regional Office for Europe
Accidental and deliberate release of
infectious agents
• Increased research, biotechnology is widely
available
• Increased risk for accidental release (e.g. SARS
2004 from laboratory)
• World tensions remain and the deliberate release
of infectious agents is no longer a remote threat.
International Health Regulation
1374
Venice
Quarantine for Plague
1851
Paris
1st International Sanitary Conference
1947
Geneva
WHO Epidemiological Information Service
1951
Geneva
International Sanitary Regulations
1969
Geneva
International Health Regulations
2004
Regional consultations
Nov 2004
Geneva Intergovernmental Working Group meeting
Feb 2005
Geneva Intergovernmental Working Group meeting
May 2005
Geneva Revised IHR, World Health Assembly
IHR Decision Instrument
4 diseases that always have to be notified
polio (wild type virus), smallpox, human
influenza caused by a novel virus, SARS.
Diseases that always lead to the use of the
algorithm : cholera, pneumonique plague,
yellow fever, VHF (Ebola, Lassa,
Marburg), WNF, meningitis, others
*Q1: serious repercussions for public
health?
Q2: unusual or unexpected?
Q3: risk of international spread?
Q4: risk of travel or traffic restrictions?
Insufficient information : re-evaluate
IHR Decision Instrument
International Health Regulation - 2005
To decide on need for notification any public health event can
be assessed by the criteria
•
Is the public health impact of the event serious?
•
Is the event unusual or unexpected?
•
Is there a significant risk of international spread?
•
Is there a significant risk of international travel or travel
restrictions ?
Obligation to establish core capacities:
•
Surveillance
•
Response
Preparedness and response - ECDC
Detection of public health threats related to infectious
disease, or of unknown origin
Risk assessment, investigation and control
Strengthening preparedness of EU member states
Strengthening and building capacity through training
Provision of technical advice and support to third
countries upon request
Epidemic Intelligence
Definition
The systematic collection and collation of information
from a variety of sources, usually in real-time, which is
then verified and analysed and, if necessary, activates
response
Objective
to speed up detection of potential health threats and
allow timely response
Epidemic Intelligence
Indicator-based surveillance
Event-based surveillance
“Surveillance” systems Data Events
Event monitoring
Collect
Capture
Analyse
Filter
Interpret
Verify
Signal
Assess
Investigate
Public
health
Alert
Control measures
Disseminate
Indicator based Surveillance
Surveillance systems
Ongoing and systematic
Collection and analysis of data
Interpretation and dissemination of results related to health
events of interest
Diagnosis-based or Syndromic surveillance
For action
Outbreak investigation
Immunization programmes
Programme planning and evaluation
Operational research hypothesis
Risk assessments
Event based Surveillance
Organized and rapid capture of information about
events that are a potential risk to public health:
• Events related to the occurrence to the
disease in humans (clusters, unusual
patterns, unexpected deaths…)
• Events related to potential exposures
(diseases in animals, contaminated food or
water, environmental hazards…)
Epidemic Intelligence
Indicator-based surveillance
Event-based surveillance
“Surveillance” systems Data Events
Event monitoring
Collect
Capture
Analyse
Filter
Interpret
Verify
Risk assessment
Early warning
Signal
Assess
Investigate
Risk Management
Public
health
Alert
Control measures
Disseminate
Response
Event based Surveillance
Sources of information:
• Hospitals/health care centres/emergency rooms
• Veterinary services, food agency
- West Nile Virus, Rift Valley Fever
- Foodborne outbreaks
• Meteorological data
- Pollution
- Heat
• Laboratories
- Identification of specific pathogens
- Increase in demand for hepatitis serology
Event based Surveillance
Sources of information
• Media
- systematic searching of news
- often in electronic format
• International networks
Indicator vs event based
Indicator based
Definitions - Clinical presentation
- Characteristics of people
- Laboratory criteria
- Specific
Timeliness - Weekly / monthly
(some may be immediate)
- Possible delay between
identification and
notification
Event based
- ...events that are a
potential risk
- ...unusual events in the
community
- Sensitive
- All events should be
reported to the system
immediately
- Real time
Indicator vs event based
Indicator based
Event based
Actors
- Involved in the system - Might not know
Reporting
structure
- Clearly defined
- No predefined structure
- Reporting forms
- Reporting forms flexible for
quali and quantitative data
- Reporting dates
- Teams to analyse data
at regular intervals
- At any time
- Teams to confirm evens
and prepare the response
Indicator vs event based
Indicator based
Event based
Trigger for
action
- a pre-defined thresholds
- a confirmed event
Response
- depends on the delay
between identification, data
collection and analysis
- depends on the
confirmation of the
event, but ideally is
immediate
A small summary
Indicator and event based systems are tools for
PH Surveillance
Event based systems have already been
successfully used
The challenge: confirmation of the events
Public Health Surveillance during
the 2012 Olympic and Paralympic Games
Helen Maguire
acknowledgements
Brian McCloskey, Director, HPS London region
Ellen Heinsbroek, EPIET fellow, HPS Colindale
London 2012 Olympic
and Paralympic Games
- 26 Olympic sports in ~34 venues
- 20 Paralympic sports in 17 venues
- 10,500 Olympic and 4,200 Paralympic athletes
- 21,000 media and broadcasters
- Over 10.2 million tickets
- 180,000 spectators per day in the Olympic Park
- 17,000 people living in the Olympic Village
What influences our
preparations for London 2012?
- Politics
- Media
- Scale
Where do we start?
What’s been learned before at other mass
gatherings?
What is the risk assessment?
What’s proportionate in relation to the risk?
What capability and capacity have we got?
What aims /objectives for our surveillance ?
Experience of mass gatherings
In Atlanta [1996] and in Sydney [2000] infectious
diseases accounted for less than 1% of
healthcare visits
In Beijing …there were no problems ..
Experience of mass gatherings
Winter Olympic Games, Torino Italy 2006
2 public and private microbiology laboratories
provided test results data for
Stool culture
Hepatitis A serology
 No difference to non-Olympic period
Data reported once a week
Experience of mass gatherings
Germany World Cup, 2006
Burden of infectious disease did not increase during World
Cup
Maintenance of daily data transmission in all Federal States
Additional free-text reporting for events through usual
surveillance system
-High sensitivity
Syndromic surveillance was regarded as not necessary
-as disease surveillance systems already in place
London Olympics Surveillance
Aim
To provide information on selected indicators
(including infection related, syndromes, and
environmental) as well as on events or incidents that
impact on Olympic venues/staff/athletes/visitors
-in order to rapidly identify any individual cases or
outbreaks /incidents so that interventions can be
implemented
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Objectives
1 review existing systems
completeness, sensitivity to unusual events /outbreaks
flexibility, timeliness, ability to detect new pathogens
2 identify gaps or limitations
3 enhance existing or establish new systems
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Enhance existing …
Enhance reportable disease by clinicians
Enhance laboratory capacity and reporting
Enhance environmental monitoring
Create 24 on-call and rapid response teams
Epidemic Intelligence
(existing and new )
1. Syndromic Surveillance (NHS Direct, Q
Surveillance, RCGP, EDSSS, OOH)
2. Notifications of Infectious Diseases
3. Surveillance at Olympic Village Polyclinics
4. Event-Based Surveillance
5. Laboratory Reporting
33
Existing and new surveillance systems
Surveillance of Undiagnosed Serious
Infectious Illness (USII)
Environmental monitoring at Centre for
Radiation, Chemical (and Environmental
Hazards Mortality Surveillance)
34
1 Syndromic Surveillance
Existing systems
NHS Direct
GP-based syndromic surveillance
• Q Surveillance
• Royal College General Practitioners
New systems
Out of Hours Providers
Emergency Departments
35
1 Syndromic Surveillance
out of hours
To provide enhanced surveillance during
weekends/holidays/evenings
1 Syndromic Surveillance
emergency departments
To establish a surveillance network of EDs across England
2 Notifications of infectious
diseases
Registered Medical Practitioner
Normal: fax: max. 3 days
Emergency: phone within 24 hrs
Proper Officer - Local Authority
Max. 3 days (methods differ by LA/HPU)
Health Protection Unit
Extra requirements Olympics:
HPA Colindale:
Central Information Management
 Olympic Venue Attendance
• Forms + HPZone to be changed
 Speed up notifications
Report published on internet
HPA Colindale:
 Improve consistency reporting
Departments (esp. Immunisation)
38
3. Surveillance at Olympic
Village
• Requirement to notify infectious diseases compulsory for
overseas athletic team doctors
• Compulsory component of temporary registration
• Same forms as medical practitioners
• Notification System being set up
• HPA presence in Olympic Polyclinic
• Monitoring of staff absences
Olympics Surveillance Systems – 3. Surveillance at Olympic Village
39
4. Event based surveillance
What is a significant event?
Standard factors – e.g. severity,
Olympic factors – proximity to venue, affecting
visitors
The media!
How do we identify significant events
HPZone – dashboard – flagging events with an
‘Olympic flag’
Regional reporting via teleconference or negative
reporting
Media screening
NOIDS
41
5 Lab reporting
Laboratories
- Weekly, by law (Oct’10)
- Automatic, with manual checking+sending
HPU/Region
Extra requirements Olympics:
HPA Colindale:
Central Information Management
- Weekly exceedance report
published on intranet
- Departments access via
software
HPA Colindale:
 Daily reporting: software
change
 Automatic extraction
software
 Exceedance Algorithms:
daily
Adapt for changes in testing,
• e.g. multiplex PCR
Departments
42
6. Surveillance of Undiagnosed
Serious Infectious Illness
To ensure early detection and response to new and
emerging infectious disease threats.
Case definition
Any person admitted to HDU/IDU
• with a serious illness suggestive of an infectious process
where the clinical presentation does not fit with any
recognisable clinical picture
• OR there is no clinical improvement in response to
standard therapy
• AND initial laboratory investigations for infectious agents
are negative
43
7 Surveillance at Centre for Radiation,
Chemical and Environmental Hazards
-increase to daily reporting
44
Olympic Surveillance Matrix: Early Detection
Surveillance
Syndromic
System Surv, (NHSD, NOIDS Olympic
Q, OOH)
Scenario
Village
Polyclinics
UK based surveillance
CRCE Laboratory
Reporting
Syndromic
Surveillance
– ED
*sentinel
Localized outbreak,
small number of cases
e.g. meningococcal
*
Localized outbreak,
large number of cases
e.g. measles
*
USII
*sentinel
Mortality
International
Situational
Analysis
(horizon
scanning)
Widespread outbreak,
small number of cases
e.g. food poisoning
Widespread outbreak,
large number of cases
e.g. influenza
Increase in weather
related disease,
e.g. asthma
Chemical,
Environmental or
Radiation incident
Imported disease,
e.g. plague
Newly emerging disease
Deliberate release,
e.g. anthrax
*
*
*
*
*
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289 days to go!
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