Outbreak Alert and Response Systems: a review February 2004 Ayana Yeneabat, MD, MPH Epidemiologist, WHO

What is an outbreak? A public health emergency! A political emergency! An economic emergency! An unusual event! An event requiring rapid action! Surveillance failure! Control failure! An opportunity !

Influenza pandemics 20th century A(H1N1)A(H2N2)A(H3N2) 1918: “Spanish Flu”1957: “Asian Flu”1968: “Hong Kong Flu” million deaths1-4 million deaths Credit: US National Museum of Health and Medicine

Total population of the SEA Region = 1.5 billion Total population at risk = 1.3 billion (87%) DF/DHF re-emerging infectious diseases No report

Source: FAO

Ebola (Viral Haemorrhagic Fever) in Africa

What is outbreak management? The process of anticipating, preventing, preparing for, detecting, responding and controlling disease outbreaks in order that health and economic impacts are minimised

Surveillance: Information for Action

Components of Effective Outbreak Management Anticipation/Prediction Preparedness Early warning/Surveillance Effective and co-ordinated response Evaluation

Components of Effective Outbreak Management Anticipation/Prediction Preparedness Early warning/Surveillance Effective and co-ordinated response Evaluation

Reported cases of encephalitis in Nepal, : Prediction/trends Week No Cases Source: EWARS

Composite rainy days x rainfall surplus (12 month accumulated figure) RVF EPIZOOTICS Davies et al Bull. WHO. 63: Effect of rainfall in producing RVF Epizootics in Kenya : Forecast/Metrological Data

Components of Effective Outbreak Management Anticipation/Prediction Preparedness Early warning/Surveillance Effective and co-ordinated response Evaluation

What should be done ? Who should do it ? What resources or supplies will be required ? Epidemic Preparedness and Response Plan

Components of Epidemic Preparedness 1 Established planning and co-ordination mechanism 2. Agreed priorities 3. Implemented epidemic preparedness plan (surveillance, response etc) 4. Functional early warning system 5. Capacity for rapid implementation of plans

Components of Effective Outbreak Management Anticipation/Prediction Preparedness Early warning/Surveillance Effective and co-ordinated response Evaluation

What is the Early Warning/surveillance objective for outbreaks? To predict, detect and confirm outbreaks of public health importance in a timely fashion and to disseminate that information to those who need to know so that effective public heath action can be taken

What are the components of an effective early warning system ? Small number of priority diseases Syndromic reporting Simple case definitions Processes for dealing with rumours Rapid case investigation and sampling Rapid laboratory confirmation Standard procedures for information sharing and initiation of response Preparedness plans in place

Outbreak Alerts: Thresholds  Absolute numbers  1 case of AFP or rabies  Relative values compared to similar period  Need to establish trend  Absolute rate over a period  Population at risk and index cases (2/100,000)  Statistical cut-offs  Time series modeling (deviations)

DAY CASES Lab confirmation Outbreak Detection and Response: no functional EWS Response Opportunity for control Detection/ Reporting First Case

DAY CASES Outbreak Detection and Response: functional EWS First Case Detection/ Reporting Confirmation R esponse Opportunity for control

How can early warning systems contribute to outbreak management ? Establish the expected Predict the future Detect the unexpected (early warning) Verify/Confirm the existence of an outbreak Monitor the evolution of an outbreak Tell you the when outbreak is over Monitor control programme!

Early warning: tracking of unusual events; Orissa, India, 2003

Mapping of Reported Disease Outbreaks, Orissa, MIS/OMDSS, 2003

Components of Effective Outbreak Management Anticipation/Prediction Preparedness Early warning/Surveillance Effective and co-ordinated response Evaluation

Confirm outbreak and diagnosis Diagnosis verified ? clinical + laboratory Link between cases? Expected numbers? Detection Routine surveillance Clinical / Laboratory General public Media

Outbreak confirmed Further investigation? Immediate control measures? Control can happen at any time during the outbreak! But you still may need to investigate

Examples of epidemic curves Point source Continuing common source Multiple waves -person to person or further outbreak

Post outbreak Tasks Prepare written report Communicate public health messages Convince public health policy Evaluate performance

PREPAREDNESSOUTBREAK CONTROL Detect & Confirm Investigate Analyse Respond Evaluate Predict & Prevent Treat Control Committee Priorities Plan Co-ordination Responsibilities Resources Supplies Training Surveillance Rapid Response

Attributes: detection, alert, response EWARN, Sudan DEWS, Pakistan KO-SURV, Kosovo EWORS, Indonesia EAST TIMOR EWARS, Nepal Global outbreak alert and response network (GOARN) Global Public Health Intervention Network (GPHIN) Orissa-MDSS/MIS/Early Warning Gujarat/Kachchh District Early Warning System NSPCD/IDSP In India: focus on early epidemics

Hallmark: information for prompt action  Timely Information  Real time transfer of information  Sound Analysis  Instant and meaningful Interpretation  Prompt and effective response  Feedback  Simple and flexible to context

Partnership: Key for EWS