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:
Download ReportTranscript 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:
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 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 1851 Paris 1947 Geneva 1951 Geneva 1969 Geneva Quarantine for Plague 1st International Sanitary Conference WHO Epidemiological Information Service International Sanitary Regulations 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 adopted 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 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 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 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 - ECDC • Identify, assess and communicate current and emerging communicable disease threats • Establish procedures for the identification of emerging health threats in cooperation with MS • 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 Intelligence Indicator-based surveillance Event-based surveillance “Surveillance” systems Data Events Event monitoring Collect Screen/collect Analyse Filter Interpret Validate Signal Investigate Assess Public health Alert Response 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 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 Indicator vs event based Indicator based Event based Definitions - Clinical presentation - ...events that are a - Characteristics of people potential risk - ...unusual events in - Laboratory criteria the community - Sensitive - Specific Timeliness - Weekly / monthly - All events should be (some may be immediate) reported to the system - Possible delay between immediately - Real time identification and notification Indicator vs event based Indicator based Actors Event based - Involved in the system - Might not know Reporting - Clearly defined structure - Reporting forms - No predefined structure - Reporting forms flexible for quali and quantitative data - At any time - Reporting dates - Teams to confirm evens - Teams to analyse data at regular intervals and prepare the response Indicator vs event based Indicator based Trigger for - a pre-defined thresholds action Response - depends on the delay Event based - a confirmed event - depends on the between identification, data confirmation of the collection and analysis event, but ideally is immediate Epidemic Intelligence Indicator-based surveillance Event-based surveillance “Surveillance” systems Data Events Event monitoring Collect Screen/collect Analyse Filter Interpret Validate Signal Assess Investigate Public health Alert Response Epidemic Intelligence - ECDC The process of Epidemic Intelligence 1. Screening/collecting 2. Filtering 3. Validating 4. Analysis 5. Assessment 6. Documentation 7. Communication Screening / Collecting: Monitoring known threats and detecting new threats by screening a virtually unlimited amount of information. 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 near real time human information intervention False positive component, duplication, overload for analysts Moderated systems rely on human moderation Time delay, human selection bias analysts reduce redundancy and false positive 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 detection Identification 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 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 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 … to know more … 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/event basedsurv.pdf Thank you for your attention