Faculty of Medicine Introduction to Community Medicine Course
(31505201)
Public Health Surveillance
By
Hatim Jaber MD MPH JBCM PhD
11- 12- 2017
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• Number of people affected by dementia to triple in next 30 years
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Post midterm
• Week 8 Unit 6: Demography and Data • Week 9 Midterm assessment (Exams.)15-11-2017 • Week 10 Unit 8 Introduction to Epidemiology. • Week 11 Unit 9: Prevention and Control of Diseases
Causation • Week 12 Unit 10: Communication and Health Education •
• Week 13 Unit 11: Public Health Surveillance and Screening
• Week 14 Unit 12: Health Administration and healthcare management • Week 15 Unit 13: Revision and Health Research
• Week 16 Final assessment (Exams.) 4-1-2018
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Presentation outline
Time
Definitions of surveillance 08:00 to 08:15
Objectives of surveillance Public health vs health care surveillance
08:15 to 08:30
Elements of a surveillance system
08:30 to 08:45
Surveillance methods
08:45 to 09:00
Surveillance system in Jordan 09:00 to 09:15
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Data Sources: Population Census
Vital registration system
Sample household surveys
Special population surveys
- Demographic (elderly, youth)
- Risk groups ( IDUs)
- Occupational (farmer, skilled labor)
- Area-based (catastrophe-affected)
Biomarkers
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Types of Information
• Surveillance – Epidemiological – Behavioral
• Routine service reporting • Special program reporting systems • Administrative systems • Vital registration systems • Facility surveys • Household surveys • Censuses • Research and special studies
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“Surveillance”
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• The word "sur-veillance" means (in
French) "to watch from above"
("veiller" = "to watch" and "sur" =
above") (i.e. a God's-eye view looking down from on-high)
• The term is often used for all forms of
observation, not just visual observation.
The word “Surveillance”
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Public health surveillance (sometimes called epidemiological surveillance) is :
the ongoing systematic collection, analysis, and interpretation of outcome-specific data essential to the planning, implementation, and evaluation of public health practice, closely integrated with timely dissemination of these data to those who need to know.
Outcomes may include diseases, injury, and disability, as well as risk factors, vector exposures, environmental hazards, or other exposures. The final link of surveillance chain is the application of these data to prevent and control human diseases and injury.
Definition of Surveillance
Surveillance is: “Information for Action”
“If you don't use it, then
do not ask for it!” However:
“Good surveillance does not necessarily ensure
the making of the right decisions, but it reduces
the chances of the wrong ones”
A. D. Langmuir (1963)
Surveillance Principle
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• In 1950, the term “surveillance” was restricted to public health practice to watching contacts of serious communicable diseases”
– To early detect symptoms
– To institute prompt treatment
– Example: Smallpox
History
• Surveillance is systematic ongoing collection,
collation, and analysis of data, and the timely
dissemination of information to those who need to
know so that action can be taken
• A survey is a one data collection episode
• Registries are not for immediate action
• Health Management Information Systems
(HMIS) for annual reports
Surveillance, surveys, registries and HMIS:
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Who Performs
Public Health Surveillance?
• Epidemiologists
• Medical professionals (doctors, nurses, clinics)
• Pharmacies
• Health insurance providers
• Emergency responders
• Public health departments (local, state, federal)
• Surveillance provides the information for descriptive
epidemiology, which is
• Person (age, sex, description)
• Place (where)
• Time (dates, hours, days, months, years)
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• Registers are archival health information
• Surveillance is dynamic as compared with surveys: Interplay between epidemiologic studies and control activities
• Surveillance is not mere: – Reporting
– Monitoring
– Data collection
Note the Differences:
Continuous versus Periodic Data Collection
Continuous Data
Collection Periodic
Collection
Data Collection Small team Large team or multiple
teams
Data accessibility Initially slow Faster turnaround
Data usefulness
for trend analysis
Ongoing results Results only after three
rounds of data collection
Evaluation of
health intervention
Continuous
monitoring of
impact
Timing of collection
often not linked to
intervention
Budget Line item in health
budget
One-off investment at
each cycle
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Public health vs health care surveillance
• Public health – protection, promotion, and restoration of
health of population
– includes health care services, especially if publicly-funded
• Health care – services provided to individuals or
communities by agents of health services or professionals to promote, maintain, monitor, or restore health.
Not limited to medical care (therapy by MD)
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Public health vs health care surveillance (cont’d)
• Health care surveillance – may be part of public health surveillance (e.g.,
Montreal DSP)
– also conducted by other agencies and/or health care organizations (e.g., hospitals)
• Population may differ – public health: usually defined geographically
(district, region, country)
– health care: recipients of services or catchment population
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• Detect outbreaks or epidemics – Detect changes in trends over time, portray natural
history of diseases – Evaluate control measures
• Estimate magnitude of morbidity and mortality – Ensure equity in health care (mortality and morbidity)
• Facilitate planning – Making projections, understanding burden of disease
and justifying allocation and or redirection of resources
• Stimulate epidemiologic research – Generate/ Test hypotheses (e.g. changes in health practice)
– Identify risk factors (in-depth studies)
Goals and Uses of Surveillance
• Early detection and prediction of outbreaks
• Description of the magnitude of disease
• Understanding risk factors for diseases
• Monitoring trends of endemic disease
• Monitor programme performance and
progress towards a control objective
• Estimate future disease impact
Objectives of Surveillance
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Surveillance objectives
Surveillance should be SMART...
S - Specific (regarding event which is subject of )
M - Measurable (gain info for comparison )
A - Action oriented (information for action)
R - Realistic & (feasible in time and place)
T - Timely (action implemented in time to be effective)
Setting objectives – balance between requirements and interests!
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•High-quality surveillance increases credibility of public health care providers: – Encourages transparency – Reduces over-reaction – Attract donors – Encourages implementation of new interventions; new
conjugate meningococcal vaccines – Facilitates better management of disease control and
other public health programs – SAVES LIVES !!!!
Added values of Surveillance
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Importance of Good Reporting
Health Care System Public Health Authority
Event Data
Information Intervention
Reporting
Feedback
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Delayed
Response
DAY
CASESOpportunity
for control
Late
Detection
First
Case
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Rapid
Response
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Early
Detection
Potential
Cases Prevented
First
Case
• Early warning indicators: – Count of cases (?)
– Attack rates (stratified) – Case-fatality rates
• Temporal component
• Defined thresholds
• Notification of cases – Suspect and probable
– Case-based data
– Immediate or weekly
Early Detection…
Delayed Detection Means =Delayed Response
Where Do We Get
Public Health Surveillance Data?
• Vital records
– Hospital records, death certificates, birth records
• Surveys – Schools, doctors, insurance companies
• Environmental monitoring systems
– Water or air quality
• Animal health data
– Veterinarians, farms, food manufacturing
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Types of Surveillance Active vs. Passive Surveillance
• Active Surveillance:
Health department solicits reports
• Passive Surveillance:
Reports are initiated by source for data
•Passive surveillance; Routine
surveillance where reports are awaited
and no attempt make actively seek
reports from the participants in the
system.
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Routine and sentinel surveillance
• Sentinel surveillance; The surveillance of a
specified health event in only sample of the
population at risk using a sample of possible
reporting sites. The sample should be representative
of the total population at risk.
• Passive surveillance; Routine surveillance where
reports are awaited and no attempt make actively
seek reports from the participants in the system.
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• Often provides an early alert for outbreaks – Most useful for diseases that occur frequently – Not intended to capture all cases
• Focal points: Clinics, hospitals or laboratories
– Strategic locations – Representative to population (socio-demographic) – High risk groups
• Less sites but better quality of data • bring attention to problems in practices, procedures
or systems • Useful for research activities
Sentinel Surveillance
•Aggregate surveillance; The
surveillance of a disease or health event
by collecting summary data on groups
of cases (e.g. in many general practice
surveillance schemes clinicians are asked
to report the number of cases of a
specified diseases seen over a period of
time).
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•Case-based surveillance; The
surveillance of a disease by collecting
specific data on each case (e.g. collecting
details on each case of Acute Flaccid
Paralysis in polio surveillance)
•Cluster; The occurrence of an unusual
number of cases in person, place
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•Community surveillance; Surveillance where the starting point is a health event occurring in the community and reported by a community worker or actively sought by investigators. This may be particularly useful during an outbreak and where syndromic case definitions can be used.
•Comprehensive surveillance; The surveillance of a specified disease or health event in the whole population at risk for that event.
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•Enhanced surveillance; The collection of additional data on cases reported under routine surveillance. The routine surveillance is a starting point for more specific data collection on a given health event. This information may be sought from the reporter, the case, the laboratory or from another surveillance data set.
• Intensified surveillance; The upgrading from a passive to an active surveillance system for a specified reason and period (usually because of an outbreak). It must be noted that the system becomes more sensitive and secular trends may need to be interpreted carefully.
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Syndromic Surveillance • Syndrome is a complex of symptoms
• Syndrome is constellation of signs and symptoms!
• Syndromic surveillance focuses on one symptom or constellation of symptoms (clinical outcomes) rather than a diagnosed disease
• No need of laboratory confirmation. Hence fast.
• More sensitive, but less specific
• Faster public health interventions For Example – WHO ALERT system for early detection of outbreaks is syndromic S. SS is surveillance for AFP (syndrome, clinical outcomes) in order to capture possible cases of poliomyelitis.
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Surveillance of Disease vs. Persons
• Surveillance of Disease:
“ The continuing scrutiny of all aspects of occurrence and spread of disease that are pertinent to its effective control”
• Surveillance of Persons:
“ The continuing scrutiny of disease contacts, high risk groups in order to promote prompt recognition of infection or illness”
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Elements of a surveillance system
• Case definition • Indicators
• Population under surveillance
• Cycle of surveillance
• Confidentiality
• Incentives to participation
• Case definition; A set of diagnostic criteria
that must be fulfilled to be regarded as a case
of a particular disease.
• Case definitions can be based on clinical
criteria, laboratory criteria or a
combination of the two.
• A case definition is a set of criteria that triggers reporting
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Elements of surveillance system: case definition
• Requirements – Indicator (not diagnostic) of trends – Simple – Feasible – Reliable – Inexpensive
• Examples – Measles: fever with red rash, red eyes, disappearing
within a week – Cholera: Sudden and severe watery diarrhoea, with rapid
and massive dehydration – Malaria: Fever, rigors, headache, body aches, inability to
carry out normal daily activities
Case definition
YES
- A “case” is an event
- An event is something that happens to:
• A person,
• In a given place,
• At a given time
- A case definition is a set of criteria that triggers reporting
NO
- A “case” is not a person
- Events do not exist if you lack info:
o On the person
o On the place
o On the onset date
- A case definition is not a diagnosis made to decide treatment
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Case definition
Includes:
Time, place, person.
Clinical features
and /or
Laboratory results
and/or
Epidemiological features
Should be:
Clear, simple
Field tested
Stable and valid
Adopted
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Case definition--three-level definitions Meningococcal disease (SURVEILLANCE PURPOSES) Possible case Clinical diagnosis of meningitis or septicaemia or other invasive disease where the consultation with the clinician and microbiologist, considers that diagnoses other than meningococcal disease are at least as likely
Probable case Clinical diagnosis of meningitis or septicaemia or other invasive disease where the consultation with the physician and microbiologist, considers that meningococcal infection is the most likely diagnosis
Confirmed case Clinical diagnosis of meningitis, septicaemia or other invasive disease AND at least one of: • Neisseria meningitidis isolated from normally sterile site • Gram negative diplococci in normally sterile site • Meningococcal DNA in normally sterile site • Meningococcal antigen in blood, CSF or urine. 42
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Elements of surveillance system: population under surveillance
• Population-based
• Institution-based
– hospitals, practices, nursing homes, prisons, schools
• Combinations
– e.g., Drug Abuse Warning Network (DAWN) in US: morbidity and mortality data on illicit drug use from hospital ERs and medical examiners/coroners
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Elements of surveillance system: cycle of surveillance
• Occurrence of health event
• Detection by health care provider
• Notification of health agency
• Analysis and interpretation
• Dissemination
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Elements of surveillance system: confidentiality
• Legally mandated reporting requires confidentiality precautions
– limited access to data (locks, passwords etc)
– encryption algorithms for coding names
• Perceived lack of confidentiality a major deterrent to completeness of reporting
– STDs
– drug use
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Surveillance methods
• Active vs passive methods
• Legally notifiable diseases
• Sentinel events
• Sentinel surveillance
• Cross-sectional vs longitudinal
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Surveillance methods: longitudinal vs cross-sectional
• Longitudinal
– Ongoing data collection
– Incident cases
– Examples: notifiable diseases, vital statistics, disease registries
• Cross-sectional
– Serial surveys
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• National:
– Periphery: (e.g., PHCC catchment area, city)
– Intermediate: Provincial
– Central
• International:
– International Health Regulations 2005
Levels of Surveillance
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• Natural and man-made disasters (emergencies) • During Special events of mass gatherings
– (Pilgrims to Makkah – Olympics
• Laboratory-based surveillance: – Emerging pathogens – Antimicrobial resistance
• Infection control • Behavioural risk factors • Others
Special Surveillance Programs
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Systems of Disease Surveillance
• Notifiable disease reporting systems • Laboratory-based surveillance
• Hospital-based surveillance
• Population-based surveillance
• Vital records (birth and death certificates)
• Registries
DEFINITIONS • Disease notification is a process of reporting
the occurrence of disease or other health-related conditions to appropriate and designated authorities.
• A notifiable disease is any disease that is required by law to be reported to government authorities.
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• A notifiable disease is one for which regular, frequent, and timely information regarding individual cases is considered necessary for the prevention and control of the disease.
• Physicians are required by law to report cases of certain infectious diseases. Unfortunately, many do not.
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Surveillance Definitions
• Active case-finding; The dynamic identification of the occurrence of a disease or health event under surveillance. (e.g. house visits by community workers to identify cases of tuberculosis).
• Active surveillance; Routine surveillance where reports are sought dynamically from participants in the surveillance system on a regular basis (e.g. telephoning each participant monthly to ask about new cases).
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•Surveillance sensitivity; The ability of a surveillance system to detect an outbreak. (The
proportion of all outbreaks that could have been detected by the system).
•Surveillance predictive value; The likelihood that an “outbreak” detected by a surveillance system is truly an outbreak
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• Survey; An investigation in which information is
systematically collected. It is usually carried out in a sample
of a defined population group and in a defined time period.
Unlike surveillance it is not ongoing though it may be
repeated. If repeated regularly surveys can form the basis of
a surveillance system.
•Zero reporting; The reporting of zero cases when
no cases have been detected by the participant.This allows
the next level of the system to be sure that the participant has
not sent data that has been lost or has
forgotten to report.
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The following should be addressed for each
disease under surveillance: • is the case definition:- clear?
appropriate? consistent throughout the surveillance system?
• is the reporting mechanism: clear ? efficient? of appropriate reporting periodicity? available to all relevant persons and institutions?
• is the analysis of data : appropriate? susceptible to proper presentation? used for decision-making?
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• do the personnel involved: have a good
understanding of the value of the surveillance
system? understand, show interest in, and support,
their own surveillance task? have enough appropriate
human and material resources?
• do the personnel involved receive appropriate:
training? supervision?
• is the feed-back from intermediate and central
levels: appropriate? sufficient? motivating?
• When the assessment of current activities is done,
the next question is:
· Is there an operational control program for each of
the priority diseases? 57
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Reporting Channels
PHC PHC PHC PHC PHC
District / Region
National Communicable Diseases Surveillance
WHO/ EMRO
WHO / HQ
CHAIN OF REPORTING
HCP DNO LG MOH
WHO/CDC FMOH SMOH Key:
HCP: Health care providers
DNO: Disease notification officer
LG MOH: Local Government Medical Officer of Health
SMOH: State Ministry of Health
FMOH: Federal Ministry of Health
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Notification
• A notification is the reporting of certain diseases or other health-related conditions by a specific group, as specified by law, regulation, or agreement.
• Notifications are typically made to the state or local health agency.
Integrated Disease Surveillance and Response (IDSR)
• IDSR form 001: For immediate/case based reporting of diseases.
• Immediate reporting allows for timely action to be taken to prevent the re-emergence or rapid transmission of epidemic prone diseases or events, especially diseases due to highly pathogenic and lethal infectious.
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Diseases/Events reported with form IDSR 001 list of
diseases/events requiring immediate reporting. • Acute Flaccid
Paralysis (AFP) • Acute hemorrhagic
fever syndrome (Ebola, Marburg, Lassa Fever, RVF, Crimean-Congo) • Adverse event
following immunization
(AEFI) • Anthrax • Chikungunya • Cholera
• Cluster of SARI • Diarrhoea with
blood (Shigella) • Dracunculiasis • Influenza due to
new subtype • Maternal death • Measles • Meningococcal
meningitis • Neonatal tetanus • Plague • Rabies (confirmed
cases)
• SARS • Smallpox • Typhoid fever • Yellow fever • Any public health
event of international
concern (infectious, zoonotic, food borne, chemical, radio nuclear or due to an unknown condition)
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• IDSR form 002: For weekly reporting of new cases of epidemic/pandemic prone diseases.
• IDSR form 003: For routine monthly notification of other diseases of public health importance.
Integrated Disease Surveillance and Response (IDSR)
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Diseases that require monthly reporting
• Acute viral hepatitis • AIDS (New Cases) • Buruli ulcer • Diabetes mellitus • Diarrhoea with
severe dehydration in children under 5 years of age
• HIV (new detections)
• Hypertension • Influenza-like illness • Injuries (Road
Traffic Accidents)
• Leprosy (quarterly) • Lymphatic Filariasis • Malaria • Malnutrition in
children under 5 years
• Mental health (Epilepsy)
• Noma • Onchocerciasis • Severe pneumonia
in children under 5years of age
• Sexually transmitted diseases (STIs)
• Trachoma • Trypanosomiasis • Tuberculosis
(quarterly) • Underweight
Newborns (less than 2500 g)
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• Vary from one country to another – Differences within countries
– Changes over time
• Adding one single disease to the list could cost a lot: Money, time, avoidable confusion
• Variables collected should be indicators of potential or arising problems rather than identifying risk factors
• Report only confirmed cases?
Reportable Diseases
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• Weekly? Appropriate most times • Monthly? Less sensitive • Quarterly? At national level • Daily?
– Daily reporting could be cumbersome – Daily reporting may be required during
emergencies, disasters
• Avoid inconsistencies in case definitions • Reporting suspected vs. confirmed cases
Frequency of Reporting Diseases
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• Should be (for line-listing): – Simple
– Minimum content
– Layout easy to understand
– Easy to reproduce
• Special data collection forms: –Special surveillance programs (e.g., Malaria, vector control)
– During outbreaks (Locally acquired or imported?)
– Eradication activities
Data Collection Forms
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Public Health Laboratories
• Fully linked to epidemiological surveillance
• Ability to confirm diagnosis of epidemic – prone diseases of national interest
• Monitor and report selected pathogens – Meningococcal meningitis and other bacterial
meningitis
– Cholera, Shigellosis and salmonellosis
– Viral Hemorrhagic fevers, etc
• Monitor antimicrobial resistance
Summaries, Interpretations,
Recommendations
Reports
Health Agencies
Health Care Providers
Public
Analysis
Information Loop of Public Health Surveillance
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Essential activities of surveillance 1. Identify; define and measure the health problem of
interest;
2. Collect and compile data about the problem (and if possible, factors that influence it)
3. Analyze and interpret these data 4. Provide these data and their interpretation to those
responsible for controlling the health problem and
5. Monitor and periodically evaluate the usefulness and quality of surveillance to improve it for future use.
N.B
surveillance of a problem does not include actions to control the problem.
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• Absolute numbers
• Proportions
• Rates
• Percentages
• Threshold
Key Indicators
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Information Management
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Evaluation of
Surveillance Systems
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• To improve existing surveillance systems
• To modify systems because of changes in
– Priorities
– Epidemiology
– Diagnostics
• To optimize the use of available resources
Goals of Evaluation of Surveillance
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International Health Regulations
2005 • Current: Notification to WHO of a case of cholera,
plague or yellow fever • IHR 2005
– Public health emergencies of international importance – Obligation to establish core capacities – Assistance to States – Context specific & flexible recommended measures – External advice (emergency and review committees)
regarding IHR
National Notifiable Disease Surveillance
• Reporting mandated by state law/regulation
• Health care providers, laboratories report to local HD (county)
• County HD submits reports to State
• Reports transmitted to CDC primarily through National Electronic Telecommunications System for Surveillance (NETSS)
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Map of 54 clinics that participated in the public health surveillance project between May – December 2014
(indicated by red dots)
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Mortality surveillance
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Influenza: laboratory surveillance
Year
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Vaccine licensed
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1963 1968 1973 1978 1983 1988 1993 1998
MEASLES — by year, United States, 1983–1998
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Year
1983 1988 1993 1998 Re
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Evaluate control measures of MEASLES United States, 1963-1998
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Table of diseases, conditions and events reported in the public health surveillance project
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Table of diseases, conditions and events reported in the public health surveillance project
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Proportional morbidity of reported communicable disease cases, excluding acute diarrhoea and chicken pox,
through the public health surveillance system between May – December 2014
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Figure 5.7 Reported Cases of Salmonellosis per 100,000 Population, By Year — United States, 1972–2002
Source: Centers for Disease Control and Prevention. Summary of notifiable diseases–United States, 2002.
Published April 30, 2004, for MMWR 2002;51(No. 53): p. 59.
•Total number of AIDS cases includes all cases reported to CDC as of December 31, 2002. Total includes cases among residents in the U.S. territories and 94 cases among persons with unknown state of residence.
Source: Centers for Disease Conrol and Prevention. Summary of notifiable diseases–United States, 2002. Published April 30, 2004, for MMWR 2002;51(No. 53): p. 59.
Figure 5.8 Reported Cases of AIDS, by Year — United States* and U.S. Territories, 1982–2002
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Measles/rubella incidence in Macedonia and immunization schedule changes in the period 1967-1997
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200
300
400
500
600
МB
/10
0.0
00
Measles
Rubella
1972 M vaccine
(13 months)
1983 МMR vaccine (13 months)
1987 М revaccine (7 years)
R revaccine (14 years
1997 МMR revaccine
(7 years)
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Remember…. Surveillance is information
for action!
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