Event based surveillance systemsAlicia Barrasa Introductory course 2012Lazareto, Menorca, Spain

Infectious diseasesArise from many different pathogens: viruses, bacteria, parasitesSpread 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, environmentalAffect all populations in all regions of the world

Emerging and Re-emerging infectious diseases

Accidental and deliberate release of infectious agentsIncreased research, biotechnology is widely availableIncreased 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 Regulation1374Venice Quarantine for Plague1851Paris1st International Sanitary Conference1947GenevaWHO Epidemiological Information Service1951GenevaInternational Sanitary Regulations1969GenevaInternational Health Regulations

2004Regional consultationsNov 2004 GenevaIntergovernmental Working Group meetingFeb 2005 GenevaIntergovernmental Working Group meetingMay 2005GenevaRevised IHR, World Health Assembly adopted

IHR Decision Instrument

IHR Decision Instrument

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:

SurveillanceResponse

Epidemic IntelligenceDefinitionThe 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

Objectiveto speed up detection of potential health threats and allow timely response

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

Surveillance is Information for action

Epidemic IntelligenceDataEventsCollect Analyse InterpretScreen/collect Filter ValidateAssessInvestigateSignalResponsePublic health AlertEvent monitoringSurveillance systemsEvent-based surveillanceIndicator-based surveillance

Indicator based SurveillanceSurveillance systemsOngoing and systematicCollection and analysis of data Interpretation and dissemination of results related to health events of interestFor actionDescribe diseasesOutbreak detectionMonitor changes /interventionsProvide evidence for policy making Generate hypothesis

Event based SurveillanceOrganized 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

Indicator vs event based

Indicator basedEvent basedDefinitions- Clinical presentation Characteristics of people Laboratory criteria

Specific- ...events that are a potential risk- ...unusual events in the community- SensitiveTimeliness- Weekly / monthly(some may be immediate)- Possible delay between identification and notification- All events should be reported to the system immediately- Real time

Indicator vs event based

Indicator basedEvent basedActors Involved in the system Might not knowReporting 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

Indicator vs event based

Indicator basedEvent basedTrigger for action- a pre-defined thresholds- a confirmed eventResponse- depends on the delay between identification, data collection and analysis- depends on the confirmation of the event, but ideally is immediate

Epidemic IntelligenceDataEventsCollect Analyse InterpretScreen/collect Filter ValidateAssessInvestigateSignalResponsePublic health AlertEvent monitoringSurveillance systemsEvent-based surveillanceIndicator-based surveillance

Epidemic Intelligence - ECDC

The process of Epidemic IntelligenceScreening/collectingFilteringValidatingAnalysisAssessmentDocumentationCommunication

Screening / Collecting:

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

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

AdvantagesDisadvantages

Automatic systemslittle or no human interventionnear real time information False positive component, duplication, overload for analystsModerated systemsrely on human moderation analysts reduce redundancy and false positive Time delay, human selection bias

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

Validation:

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

Early detectionIdentification of signals

Analysis:

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

Risk Assessment

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

Communication:

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

Epidemic Intelligence - ECDC

A small summaryIndicator and event based systems are tools for PH Surveillance

event based systems have already been successfully used

The challenge: confirmation of the events

Epidemic Intelligence at ECDC24/7 Screening of news from different sourcesRound tableDaily threat assessmentDaily & weekly reportsCommunicationRisk assessmentResponse to outbreaks

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):665WHO. A guide to establishing event-based surveillance http://www.wpro.who.int/internet/resources.ashx/CSR/Publications/eventbasedsurv.pdf to know more

Thank you for your attention

The history of international health regulations is believed to have begun with quarantine legislation enacted by the city of Venice in 1377 (1), and the principle of aiming for maximum protection with minimum restriction was laid down at the first international sanitary conference, held in 1851 (1). The International Health Regulations (IHR) are intended to provide a code of practice to be followed by all countries in order to control diseases that threaten international health. Cholera, plague, and yellow fever are the three diseases currently notifiable to the World Health Organization and subject to IHR control measures at ports of entry and departure from countries (1). The regulations are being revised in response to increasing international traffic and changing patterns of communicable diseases. Under the revised IHR, disease outbreaks will be notifiable only if they correspond to the case definition of a specified syndrome and represent events of urgent international importance (2). The routine occurrence of endemic diseases - such as cholera - will no longer be notifiable. The syndromes proposed are as follows:acute haemorrhagic feveracute respiratoryacute diarrhoealacute jaundiceacute neurological"other notifiable syndromes of presumed infectious origin"The criteria by which urgent international importance is to be judged are:high risk of international spreadunexpectedly high case fatality rateunusual occurrencenewly recognised syndromemedia interestpotential for imposition of trade or travel restrictionsA pilot study in 20 countries (including France, Russia and Uzbekistan) has been set up to evaluate the proposed new approach to notification. National health authorities will assess reports of outbreaks in their own countries in the light of the new case definitions and criteria for importance to see whether the new approach will facilitate the identification of and response to disease outbreaks

The International Health Regulations originated with the International Sanitary Regulations adapted at the International Sanitary Conference in Paris in 1851. The cholera epidemics that hit Europe in 1830 and 1847 made apparent the need for international cooperation in public health. In 1948, the World Health Organization Constitution came about. The Twenty-Second World Health Assembly (1969) adopted, revised and consolidated the International Sanitary Regulations, which were renamed the International Health Regulations (1969). The Twenty-Sixth World Health Assembly in 1973 amended the IHR (1969) in relation to provisions on cholera. In view of the global eradication of smallpox, the Thirty-fourth World Health Assembly amended the IHR (1969) to exclude smallpox in the list of notifiable diseases.During the Forty-Eighth World Health Assembly in 1995, WHO and Member States agreed on the need to revise the IHR (1969). The revision of IHR (1969) came about because of its inherent limitations, most notably:narrow scope of notifiable diseases (cholera, plague, yellow fever).[1] The past few decades have seen the emergence and re-emergence of infectious diseases. The emergence of new infectious agents Ebola Hemorrhagic Fever and the re-emergence of cholera and plague in South America and India, respectively; dependence on official country notification; and lack of a formal internationally coordinated mechanism to prevent the international spread of disease. These challenges were placed against the backdrop of the increased travel and trade characteristic of the 20th century.The IHR (2005) entered into force, generally, on 15 June 2007, and are currently binding on 194 countries (States Parties) across the globe, including all 193 Member States of WHO.

Sources of information:

Hospitals/health care centres/emergency roomsVeterinary services, food agencyWest Nile Virus, Rift Valley FeverFoodborne outbreaksMeteorological dataPollutionHeatLaboratoriesIdentification of specific pathogensIncrease in demand for hepatitis serology