Surveillance: Definition, Goals and Methodology Michael O. Favorov M.D., Ph.D., D.Sc. Deputy Director-General, Director of Translational Research Division, International Vaccine Institute

PUBLIC HEALTH The science and art of preventing disease, prolonging life, and promoting health through organized efforts of society

Mortality rate due to major causes, Kg Republic, 1999

Years of Potential Life Lost (65) due to major causes, Kg Republic, 1999 years of potentially lost life

Surveillance Surveillance is the ongoing systematic collection, collation, analysis, interpretation of data; dissemination of information to those who need to know in order that action may be taken

TB Reported Incidence and Mortality Rates, Kazakhstan, Source: Kz NTBC DOT S

Rationale for Disease Surveillance Public health importance of the disease? Public health importance of the disease? Can public health action be taken? Can public health action be taken? Are relevant data easily available? Are relevant data easily available? Is it worth the effort (money, human resources)? Is it worth the effort (money, human resources)? (Pediculosis vs. Lousiness, Vitiligo)

Is the disease a priority ? JE in Asia and Latin America What are the objectives of surveillance ? (monitor cases and deaths from Rotavirus or/and Typhoid Fever to evaluate control measures) What data will be required to generate the indicators and what sources of data exist? What disease indicators will be used? (the number of new cases per 100,000? or/and the number of deaths) PRIORITY OBJECTIVES MINIMUM DATA AND DATA SOURCES TARGET POPULATION What is the population in which we wish to detect cases ? (all, high risk groups..) INDICATORS

What are the Objectives of Surveillance?

Objectives of Surveillance Epidemic (Outbreak) detection Monitoring trends in endemic disease Evaluating an intervention Monitor progress towards a control objective Monitor programme performance Epidemic (Outbreak) prediction Estimate future disease impact

Cases of acute bloody diarrhoea in a rural district by month, January April 1995 Objective: To detect outbreaks of dysentery by monitoring the incidence of cases of acute bloody diarrhoea

To monitor the incidence and case fatality rate of Typhoid Fever in children under 5 years Cases and deaths from Typhoid Fever in a rural districts Objective : Drug availability? Resistance to drugs? Environmental Factors? Human-related Factors?

How to identify the cases? Hospital based surveillance for rotavirus in Uzbekistan, Surveillance

To monitor progress towards polio eradication by monitoring the incidence of poliomyelitis where wild poliovirus is isolated in children under 14 years Cases of poliomyelitis where wild poliovirus was isolated in children in a rural district, Objective:

To monitor the incidence of laboratory confirmed Typhoid Fever cases among clinical cases Cases in a region, Objective:

Measure the HIV reported cases to predict future trends Cases of HIV in the country, Objective:

To measure the incidence of AIDS to predict future trends and facilitate health service planning Cases of AIDS in a city district, Objective:

To monitor the ability of a TB programme to ensure treatment completion and cure Treatment completion and cure in TB cases, Objective:

Disease Indicators The measures that you use to monitor a disease Number Number Number of cases of Typhoid Fever reportedNumber of cases of Typhoid Fever reported Number of cases of Typhoid Fever among overall fibril illnesses cases reportedNumber of cases of Typhoid Fever among overall fibril illnesses cases reported Rate Rate Number of cases of Typhoid Fever in children under 5 years per 100,000 populationNumber of cases of Typhoid Fever in children under 5 years per 100,000 population Ratio Ratio Proportion of children with Rotavirus who dieProportion of children with Rotavirus who die

Surveillance: Indicators Specific Measurable Action oriented Realistic Timely

Surveillance: General Principle Health Care System Public Health Authority Data Information Decision Action Feedback Reporting Evaluation Analysis & Interpretation

Surveillance: Data 1 Health Care SystemPublic Health Authority Information Decision Action HEALTH EVENT Disease Syndrome (e.g., AFP, jaundice, VHF) Public health issue Environment (e.g., vectors, water )

Surveillance: Data 2 Health Care SystemPublic Health Authority Information Decision Action DATA SOURCE Notifiable disease reporting system Vital statistics Survey Laboratory

Surveillance: Data 3 Health Care System Public Health Authority Information Decision Action CASE DEFINITION Clinical/laboratory Levels (suspected, probable, confirmed) Indicators

Surveillance: General principle Health Care System Public Health Authority Data Information Decision Action Feedback Reporting Evaluation Analysis & Interpretation

Surveillance: Reporting Health Care SystemPublic Health Authority DataInformation Decision Action Reporting frequency immediate weekly monthly...

Surveillance: Reporting Health Care System Public Health Authority DataInformation Decision Action Reporting methods Paper Telephone, Fax Internet based...

Surveillance: General Principle Health Care System Public Health Authority Data Information Decision Action Feedback Reporting Evaluation Analysis & Interpretation

Surveillance: Analysis & Interpretation Health Care SystemPublic Health Authority Data Decision Action Data characteristics Data validation Descriptive analysis Hypothesis generation

Surveillance: Analysis & Interpretation Health Care System Public Health Authority Data Decision Action Missing values Bias Duplication Data validation

Surveillance: Analysis & Interpretation Health Care SystemPublic Health Authority Data Decision Action Time Place Persons Descriptive analysis

Surveillance: Analysis & Interpretation Health Care SystemPublic Health Authority Data Decision Action related to time related to place related to persons Hypothesis generation

Surveillance: General Principle Health Care System Public Health Authority Data Information Decision Action Feedback Reporting Evaluation Analysis & Interpretation

Surveillance: Action Health Care System Public Health Authority Data I nformation Decision Action Control Feedback Policy

Surveillance: Action Health Care System Public Health Authority Data I nformation Decision Action Control Rapid response Case management Prevention (e.g. immunization)

Surveillance: Action Health Care System Public Health Authority Data I nformation Decision Action Feedback Reports Epidemiological bulletin Personal contacts

Surveillance: Action Health Care System Public Health Authority Data I nformation Decision Action Policy Policy change Prediction, planning Epidemic preparedness

Surveillance: General Principle Health Care System Public Health Authority Data Information Decision Action Feedback Reporting Evaluation Analysis & Interpretation

Surveillance: Action Health Care System Public Health Authority Data I nformation Decision Action Evaluation results of action results of surveillance

Surveillance: General Principle Health Care System Public Health Authority Data Information Decision Action Feedback Reporting Evaluation Analysis & Interpretation

Ministry of Health WHO Peripheral (Local) level Intermediate level Central level Regional/International level Surveillance: Data flow Clinical (suspected) + Supportive laboratory data + epidemiological link (probable) Diagnostic Laboratory (confirmed) Regional reference laboratory

Ministry of Health WHO Peripheral level Intermediate level Central level Regional/International level Surveillance: Tasks Detect Treat Report Analyse Investigate Report Respond Feedback Investigate Confirm Respond Plan and Fund Feedback Funding Analysis and feedback Support Policy recommendation

Exposed Clinical specimen for test Disease Disease Pos. specimen Infected Seek medical attention Report Surveillance Data Distribution Pattern

Exposed 100% Infected/Immune 95% Hepatitis A Data Distribution Pattern Clinical specimen for test Disease 1-2% Disease 1-2% Pos. specimen Seek medical attention Report <1%

Disease-specific surveillance

Laboratory Diagnostics can only function as a system Quality Control Cycle

Consecutive testing of ten serum aliquoted samples from a single hepatitis B patient (11 aliquots; One month period; City Laboratory)

Surveillance: Function Core function DetectionDetection ReportingReporting Investigation & confirmationInvestigation & confirmation Analysis & interpretationAnalysis & interpretation Action / responseAction / response Support function TrainingTraining SupervisionSupervision ResourcesResources Standards / guidelinesStandards / guidelines

Surveillance: Basic Components A good network of motivated people Efficient communication system Clear case definition and reporting mechanism Basic but sound epidemiology Good feedback and rapid response Laboratory support

Obstacles Limited use of data for development, direction, or evaluation of public health policy In many settings outbreaks meant that medical personal were not performing their duties of preventing and controlling infectious diseases

Critical Challenges Assurance of usefulness Computer technology Application to new areas Educate public and policy makers Flexibility Cost effective

Surveillance Conclusion Social impact, economic burden, control, prevention, and in many cases, even existence of the diseases for the society resulting of the surveillance completeness, accuracy, and practicality Social impact, economic burden, control, prevention, and in many cases, even existence of the diseases for the society resulting of the surveillance completeness, accuracy, and practicality