1. Key elements in a surveillance system Patrick Rolland
EPIET / EUPHEM Intro Course 2012
&

2. Le fil rouge in surveillance?
Surveillance is
Information for action!

3. Good reminder: surveillance?
Langmuir AD., 1963
“Systematic collection, consolidation, analysis and dissemination of data on specific disease”
Thacker SB., 1996
“The final link is the application of these data to prevention and control”

4. Good reminder: surveillance loop
Objectives
Evaluation
Data collection
Data analysis
Action!
Information

5. Aim and content of the lecture
Aim: To understand key elements in a surveillance system
From a clear understanding of the purpose
To the right dissemination of information
Content
Main objectives of a surveillance system
Checklist of key elements, step by step

6. Main objectives of
a surveillance system

7. Main objectives Describe: produce information in terms of TPP
Alert: detect epidemics or emerging events
Evaluate: assess prevention or control measures
And also:
Generate hypotheses for research
Detect changes in health practice
Plan public health actions and resources

8. Information for action!
But keep in mind the goal!
Surveillance is
Information for action!
By implementation of prevention and control measures
In order to reduce morbidity and mortality

9. Describe: Time = Graph
Weekly incidence rate of flu-like syndromes, , France
Source: GP network “Réseau unifié”
Incidence (per 100,000)
Week

10. Describe: Place = Map Weekly incidence rate of acute diarrhea
(per 100,000)
1 to 7 march 2012, France
Source: GP network “Réseau sentinelles”

11. Characteristics of persons
Describe: Person = Table
Characteristics of persons
Severe cases of influenza, winter , France
Source: Intensive care units Network
Burden

12. Alert: detect an epidemic
Weekly incidence of flu-like syndromes, , France
Source: GP network “Réseau sentinelles”
Incidence
Threshold
Exceedence
Incidence (per 100,000)
Week

13. Source: InVS, NRC for meningococci
Alert: detect an emerging phenomena
Invasive meningococcal infections by serogroup B, C, W135 et Y, , France
Source: InVS, NRC for meningococci B C
W135 Y
Number of cases
Emergence of W135
Year

14. Evaluate: prevention/control measure
Cases of Pertussis, England and Wales,
Vaccination
implementation 80 40
Number of cases (x 1000)
Vaccinate coverage (%)
Year

15. Evaluate: prevention/control measure
Cases of legionellosis, , France
Source: Notifiable disease, InVS
No cases
Incidence
Reinforced surveillance New investigation guide Urine antigen testing
Number of cases
Incidence (per 100,000)
Year

16. Key elements in a
surveillance system

17. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

18. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

19. Justification of implementation
Ask yourself two main questions:
Should this event be under surveillance?
High frequency?
High severity?
High socioeconomic cost?
Do some prevention or control measures exist?
And these two additional questions:
Do we have existing data that already answer?
Do we have resources to set up a new system?

20. Health events under surveillance
Infectious diseases
Notifiable diseases
Health-care associated infections (HCAI)
Vaccine-preventable diseases
Food and waterborne diseases
Sexually transmitted infections (STI)
Zoonoses
Vector-borne diseases
But also?

21. Health events under surveillance
Chronic diseases and injuries: cancers, accidents, traumas, cardiovascular diseases, etc.
Occupational health: cancers, musculoskeletal disorders, respiratory diseases, mental health, etc.
Environmental hazards: air pollution, ionizing radiations, heat/cool waves, water/soil pollution, etc.

22. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

23. Objectives of the system
Primary objective: To describe a health-related event in population-based or in a specific population
With two possible aims (sometimes both):
To alert by early detection of epidemics or emerging pathologies that need timely action
To evaluate the efficiency of prevention or control measures

24. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

25. Passive and active system
Consideration useful for discussion
Passive: “The data come to you”
Data collection based on existing information
Simple, not burdensome but could be incomplete
E.g.: notifiable diseases, deaths, emergency data
Active: “You go towards the data”
Data collection specially set up
Good quality of data but required resources
E.g. : injuries, non-notifiable infectious diseases, etc.

26. E.g. of passive system
% of gastroenteritis among emergency consultations, seasons and , Aquitaine, France
Proportion of cases
Week

27. E.g. of active system
Cases of envenomation by Physalia Physalis reported by lifeguards, Aquitaine Atlantic Coast, Summer 2011, France
Number of cases
Day

28. Exhaustive vs. sentinel system
Important consideration for data analysis
Severe diseases or low-frequency diseases requiring timely action
Exhaustive system (= all providers)
E.g.: cancers registries, notifiable diseases
High-frequency diseases or less-severe diseases
Sentinel system (= selected providers)
E.g.: seasonal flu, occupational diseases (except cancers)

29. Cancers among women, Year 2005, Gironde, France
E.g. of exhaustive system
Cancers among women, Year 2005, Gironde, France
Source: Cancer registry of Gironde
Cancer causes
1. Breast cancer
2. Colorectal cancer
3. Skin cancer
Number of cases

30. E.g. of sentinel system
Prevalence of occupational diseases (except cancers), Year 2010, Region of Aquitaine, France
Source: Sentinel Network of occupational physicians (n=92)

31. Case vs. syndromic system
Case system (traditional system)
Targets a defined health-related event
E.g.: mesothelioma, Lyme disease, diabetes, etc..
Syndromic system (“before diagnosis”)
For early detection, evaluation of event impact
Based on existing activity data, real-time collection, analysis and interpretation data
E.g.: emergency services, virology labs, deaths certificates, medicine sales, absence in schools, etc.

32. E.g. of case system Occupations at risk for mesothelioma, France
Source: Program of Mesothelioma Surveillance ( ), InVS
Occupations
Odds-ratio (95% CI)

33. E.g. of syndromic system
% of gastroenteritis among emergency consultations, seasons and , Aquitaine, France
Proportion of cases
Week

34. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

35. Case definition The “heart” of the system! Must be clear and simple
Based on criteria: clinical, biological, epidemiological
May include:
Classification (possible, probable, confirmed)
TPP (Time-Place-Person) information

36. Epidemiological criteria
Clinical criteria
E.g. for measles definition as notifiable disease
Laboratory criteria
Source:
Case definitions of notifiable diseases
Commission Decision 2008/426/EC – 28-IV-2008
Epidemiological criteria
Case classification

37. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart of data and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

38. Population under surveillance
Depends on characteristics of health-event
E.g.: Hemolytic Uremic Syndrome (HUS)
Rare disease that predominantly affects children, needs timely action in outbreak
Population under surveillance (France): children (< 15 years) hosted in pediatric and nephrology hospital services (N=31)

39. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

40. Data providers and data sources
Data providers: health professionals, laboratories, health insurance funds, civil status offices, etc.
Data sources
Administrative: death certificates, hospital systems, etc.
Medical: patients folders, notifiable diseases, etc.
Biological: virology, bacteriology, toxicology samples
Environmental: air pollution sensors, individual ionizing radiations card for exposed workers, etc.

41. 47 National Reference Centers and 34 Associated Laboratories
E.g. data provider: NRC (France)
47 National Reference Centers and 34 Associated Laboratories
One NRC per infectious disease
Anaérobies et Botulisme (LA)
Arbovirus (LA)
ATNC
Brucella
Borrelia (LA)
Campylobacter & Helicobacter
Charbon (LA)
Chlamydiae
Cytomégalovirus
Enterovirus
Escherichia coli & Shigella (LA)
Francisella tularensis
Gonocoques
Haemophilus influenzae
Legionella
Leishmania
Mycobactéries et résistance des mycobactéries
Paludisme (2 co-responsables)
Pneumocoques
Résistance aux antibiotiques (LA)
Rickettsia, Coxellia & Bartonella Virus de la rougeole
Staphylocoques VIH
Streptocoques Virus Influenza
Syphilis Virus entériques
Trichinella Virus des hépatites A et E
Toxoplasmose Virus des hépatites B, C et Delta
Arbovirus
Arbovirus & influenza virus en AG
Charbon
Borrelia
Anaérobies et Botulisme
Chimiorésistance du paludisme
en Antilles Guyane
Coqueluche et autres bordetelloses
Corynebactéries toxinogènes
Escherichia coli & Shigella
Fièvres hémorragiques virales
Leptospires
Listeria
Méningocoques
Mycologie et antifongiques
Peste et autres yersinioses
Rage
Salmonella
Résistance aux antibiotiques
Streptocoques (LA)
Virus des Hépatites B & C (LA)
Vibrions et cholera
Virus Influenza
15 NRC
and 3 AL
Pasteur Institute
(Paris)
32 NRC and 31 AL
Within hospitals,
universities, other
research institutes

42. E.g. data source: ND (France)
27 notifiable diseases (ND) require surveillance and timely action
Frequent ND (n=14)
Infrequent ND (n=10)
Botulisme
Brucellose
Chikungunya
Dengue
Fièvres typhoïdes et paratyphoïdes
Hépatite aiguë A
Infections invasives à méningocoques
Légionellose
Listériose
Rougeole
Saturnisme de l’enfant mineur
MCJ et ESST
Toxi-infection alimentaire collective
Tuberculose
Choléra (RSI)
Diphtérie
Fièvres hémorragiques africaines
Fièvre jaune (RSI)
Paludisme autochtone et paludisme importés dans DOM
Peste (RSI)
Poliomyélite
Rage
Typhus exanthématique
Bioterrorism-related ND (n=3)
Charbon, Tularémie, Variole
4 ND require surveillance only
Infection à VIH quel qu’en soit le stade
Hépatite aiguë B
Tétanos
Mésothéliome
(entrée en 2012)

43. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart of data and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

44. E.g. French form for mesothelioma notiable disease
Nominative data on patient and provider
E.g. French form
for mesothelioma
notiable disease
Anonymous data on patient diagnosis (by clinician&pathologist)
Dates and signatures of provider and sanitary authority

45. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

46. E.g. of flow chart: ND (France)
Politic of Health
Public Health High Council
Declaration
Health Regional Agencies
Patient
Alert
Ministry of Health
Health professionals, laboratories, etc.
Reference Centers
Alert
Partners
National/International
Experts Networks
Clinicians/Pathologists

47. Data transmission Reliable and fast Low frequency Secure
Electronic: s, websites
And: phone, fax and mail
Low frequency
Daily
Weekly
Monthly
Secure
Regularity, punctuality, exhaustiveness
And don’t forget the “Zero reporting”

48. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

49. Data validation and data analysis
Missing data
Duplicates
Data quality
Data analysis
Indicators: frequency, severity
Methods: descriptive, analytical
Illustrations: tables, graphs and maps
Keep in mind: Time-Place-Person!

50. E.g. of data analysis: time series
Daily deaths, summers vs. 2003, France
Source: Syndromic Program, InVS
Temperature
Deaths
2003
Number of deaths
Temperature (°C)
Day (25 June to 19 august)

51. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

52. Dissemination/communication data
Systematic and regular
For stakeholders, decisions makers
For other professionals, public, medias
Adapted
To “Those who need to know”
To the urgency of the situation
Format
Report, article, flash news, press release etc.
But also: phone, , fax, mail
Factor of motivation/improvement

53. E.g. report at local level
“Point épidémio”
France, Bordeaux
(InVS, south west)
Weekly report on health status of population
Topics:
Outbreaks
Seasonal pathologies
Notifiable diseases
Virology surveillance
Deaths

54. E.g. report at international level
CDC (USA)
WHO (Switzerland)

55. E.g. press release At local level (e.g. France, Bordeaux)
At international level (e.g. Europe)

56. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

57. Human and financial resources
From the budget to the expenses
Salaries, travels, equipments, furniture, etc.
Useful to negotiate resources, check the workplan, assess the cost of the system

58. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

59. Data security and confidentiality
“Critical point” in surveillance system
Public heath data
Often personal and private in nature
Might directly identified individuals
Take into account policies and protection for personal data
Data collection often under laws

60. Key elements Justification of implementation Objectives of the system
Types of system
Case definition
Population under surveillance
Data providers and data sources
Data elements and data collecting tools
Flow chart and data transmission
Data validation and data analysis
Dissemination and communication data
Human and financial resources
Data security and confidentiality
Evaluation of system

61. Aims of evaluation Ask yourself the fundamental question:
Have the objectives been met?
And these additional questions:
Did the system generate needed answers?
Was the information timely?
Was it useful for decisions makers?
How was the information used?
What could be done to improve the “attributes”?
Is it useful to continue the surveillance?

62. The “9” attributes of a system (1)
Simplicity: refers to structure and ease operation
Flexibility: ability to adapt to changing needs
Data quality: refers to data completeness&validity
Acceptability: willingness of persons and organizations to participate
Sensitivity: refers to proportion of detected cases by the system (“A / A + C”)

63. The “9” attributes of a system (2)
PVP: refers to proportion of reported the cases that actually have the event (“A / A + B”)
Representativeness: ability to describe the event over time and its distribution in the population
Timeliness: reflects the speed between system steps of the system
Stability: refers to reliability and availability

64. Conclusion

65. Main messages Justification Objectives and aims Requirements
Relevance of the event to be under surveillance
Existence of prevention and control measures
Objectives and aims
To describe – To alert – To evaluate
To produce information for action
In order to reduce morbidity and mortality
Requirements
“Good data”, involvement of stakeholders
Regular evaluation of the system

66. One useful book
3rd edition
September 2010
Lisa M. Lee
et al.

67. Don’t forget the surveillance loop!
Objectives
Evaluation
Data collection
Data analysis
Action!
Information

68. Le fil rouge in surveillance?
Surveillance is
Information for action!