public health surveillance - كلية الطب€¦ · estimate magnitude of morbidity and...

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

DAY

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

Re

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Th

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sa

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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

po

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(Th

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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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100

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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