Definition
Public health surveillance is the continuous, systematic collection, analysis and interpretation of health‑related data needed for the planning, implementation and evaluation of public‑health practice, closely integrated with the timely dissemination of these data to those who need to know and linked to public‑health action. (WHO 2024; CDC 2024)
Strategic Objectives
- 1Early detection of unusual public‑health events and emerging threats.
- 2Monitoring trends in disease incidence, prevalence and determinants.
- 3Guiding interventions and resource allocation for prevention and control.
- 4Evaluating impact of policies and programmes.
- 5Supporting research and innovation for healthier populations.
- 6Enabling global health security through data sharing and collaboration.
Key Steps in the Surveillance Cycle
Figure 1. Continuous surveillance cycle linking data collection, analysis, interpretation and public‑health action (WHO 2024).
Types of Disease Surveillance
| Type | Description | Typical Use / Examples |
|---|---|---|
| Passive | Routine reporting from healthcare facilities to public‑health authorities. | National notifiable disease reporting systems. |
| Active | Regular outreach to collect data proactively. | Outbreak field investigations; special studies. |
| Sentinel | Selected sites report high‑quality, detailed data. | Influenza‑like illness networks (e.g., ECDC TESSy). |
| Laboratory‑based | Surveillance using laboratory test results. | Genomic sequencing for SARS‑CoV‑2 variants. |
| Syndromic | Uses pre‑diagnostic symptom data for early warnings. | Emergency‑department fever surveillance (Africa CDC EBS). |
| Event‑based | Rapid collection and analysis of unstructured information about events. | Media monitoring for unusual clusters (Gulf CDC media scanning). |
References
- 1. World Health Organization (2024). Surveillance in Emergencies. Retrieved from https://www.who.int/emergencies/surveillance
- 2. Centers for Disease Control and Prevention (2024). Introduction to Public Health Surveillance. Retrieved from https://www.cdc.gov/training-publichealth101
- 3. European Centre for Disease Prevention and Control (2022). Long‑Term Surveillance Framework 2021–2027. Retrieved from https://www.ecdc.europa.eu/
- 4. Africa CDC (2023). Event‑Based Surveillance Training Manual. Retrieved from https://africacdc.org/
- 5. Gulf CDC (2024). Towards a Unified Regional Surveillance System. Frontiers in Public Health. Retrieved from https://www.frontiersin.org/
- 6. McNabb, S. J., German, R. R., Lee, L. M. (2021). Transforming Public Health Surveillance. Elsevier.