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Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

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Page 1: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Event based surveillance systems

Alicia Barrasa

Introductory course 2012

Lazareto, Menorca, Spain

Page 2: Event based surveillance systems Alicia Barrasa Introductory course 2012 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

Page 3: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Emerging and Re-emerging infectious diseases

Cryptosporidiosis

Dengue haemhorrhagic feverCholera

E. coli O157

Typhoid

Diphtheria

E. coli O157

Lassa fever

Dengue haemhorrhagic fever

Cholera

Multidrug resistant Salmonella

E.coli non-O157Malaria

Legionnaire’s disease

Buruli ulcer

Shigellosis

Typhoid

Shigellosis

Cholera O139

Respiratoryinfection

Kyasanur f.Lyme Borreliosis Reston

Venezuelanequine encephalitis

West Nile Fever

EchinococcosisYellow fever

Ebola haemorrhagicfever Human

monkeypox

Influenza A (H5N1)

RVF/VHF

Ross River virus

Hendra virus

BSEWest Nile Virus

Nipah Virus

SARS

Human monkepox

O’nyong-nyong fever

Reston Virus

Rabies

nvCJD

Epidemic Alert and Response (EAR), WHO Regional Office for Europe

A(H1N1)v

Page 4: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

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.

Page 5: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

International Health Regulation1374 Venice Quarantine for Plague1851 Paris 1st International Sanitary Conference1947 Geneva WHO Epidemiological Information

Service1951 Geneva International Sanitary Regulations1969 Geneva International Health Regulations

2004 Regional consultationsNov 2004 Geneva Intergovernmental Working

Group meetingFeb 2005 Geneva Intergovernmental Working

Group meetingMay 2005 Geneva Revised IHR, World Health

Assembly adopted

Page 6: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

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 graves 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

Page 7: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

IHR Decision Instrument

Page 8: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

International Health Regulation - 2005To 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

Page 9: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

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

Page 10: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Epidemic Intelligence - ECDC

• Establish procedures for the identification of emerging health threats in cooperation with MS

• Identify, assess and communicate current and emerging communicable disease threats

• Inform EC and MS about emerging health threats requiring their immediate attention

• Communication on emerging health threats, including to the public

Page 11: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Surveillance is

Information for action

Page 12: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Epidemic Intelligence

Data EventsCollectAnalyseInterpret

Screen/collectFilterValidate

AssessInvestigate

Signal

Response

Public health Alert

Event monitoring“Surveillance” systems

Event-based surveillanceIndicator-based surveillance

Page 13: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Indicator based Surveillance

Surveillance systems• Ongoing and systematic

– Collection and analysis of data – Interpretation and dissemination of results

related to health events of interest

• For action– Describe diseases– Outbreak detection– Monitor changes /interventions– Provide evidence for policy making – Generate hypothesis

Page 14: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

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…)

Need confirmation

Page 15: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Indicator vs event based

Indicator based Event based

Definitions - Clinical presentation

- Characteristics of people

- Laboratory criteria

- Specific

- ...events that are a potential risk

- ...unusual events in the community

- Sensitive

Timeliness - Weekly / monthly

(some may be immediate)

- Possible delay between identification and notification

- All events should be reported to the system immediately

- Real time

Page 16: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Indicator vs event based

Indicator based Event based

Actors - Involved in the system - Might not know

Reporting structure

- Clearly defined

- Reporting forms

- Reporting dates

- Teams to analyse data at regular intervals

- No predefined structure

- Reporting forms flexible for quali and quantitative data

- At any time

- Teams to confirm evens and prepare the response

Page 17: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

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

Page 18: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Epidemic Intelligence

Data EventsCollectAnalyseInterpret

Screen/collectFilterValidate

AssessInvestigate

Signal

Response

Public health Alert

Event monitoring“Surveillance” systems

Event-based surveillanceIndicator-based surveillance

Page 19: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Epidemic Intelligence - ECDC

Page 20: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

The process of Epidemic Intelligence

1. Screening/collecting

2. Filtering

3. Validating

4. Analysis

5. Assessment

6. Documentation

7. Communication

Page 21: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Screening / Collecting:

Monitoring known threats and detecting new threats by screening a virtually unlimited amount of information.

Page 22: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

web-based early warning systems

Sophisticated applications able to gather, filter and classify web-based information for public health purposes

• Advantages Disadvantages

Automatic systems little or no human intervention

near real time information

False positive component, duplication, overload for analysts

Moderated systems rely on human moderation

analysts reduce redundancy and false positive

Time delay, human selection bias

Page 23: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Filtering:

The objective of filtering is to decide which information detected through screening might be potential public health events of National, European or international concern.

Early detection

Page 24: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Validation:

This is the process of confirming the accuracy and credibility of information received from non-official sources (unverified information).

Early detection

Identification of signals

Page 25: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Analysis:

Initial evaluation based on preliminary info available in terms of likelihood and of possible human public health impact

Risk Assessment

Page 26: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Documentation:

Logging information and actions taken during the EI process from the beginning is a crucial action to analyse the ongoing situation and to trace back all the steps

Page 27: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Communication:

To public/media and to scientific community about findings and assessment of potential public health events detected and investigated

Page 28: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Epidemic Intelligence - ECDC

Page 29: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

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

Page 30: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Epidemic Intelligence at ECDC• 24/7 Screening of news from different sources• Round table

– Daily threat assessment– Daily & weekly reports– Communication

• Risk assessment• Response to outbreaks

Page 31: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

WHO. The revision of the International Health Regulations. Wkly Epidemiol Rec 1996; 71: 233-5

WHO. Revision of the International Health Regulations: progress report, January 1998. Wkly Epidemiol Rec 1998; 73: 17-9

Paquet C, Coulombier D, Kaiser R, Ciotti M. Epidemic intelligence: a new framework for strengthening disease surveillance in Europe. Euro Surveill. 2006;11(12):665

WHO. A guide to establishing event-based surveillance http://www.wpro.who.int/internet/resources.ashx/CSR/Publications/eventbasedsurv.pdf

… to know more …

Page 32: Event based surveillance systems Alicia Barrasa Introductory course 2012 Lazareto, Menorca, Spain

Thank you for your attention