Surveillance Defined
Surveillance is the ongoing systematic collection, analysis and interpretation of outcome-specific data for use in the planning, implementation and evaluation of public health practice. Surveillance can have a negative connotation, but we can use it to:
- Identify patients and their contacts for treatment and intervention
- Detect epidemics, health problems, changes in health behavior
- Estimate magnitude and scope of health problems
- Measure changes in infectious and environmental agents
- Assess effectiveness of programs
- Develop hypotheses and stimulate research
Modes of Surveillance
Active Surveillance
- Health agencies reach out to health care providers
- More complete reporting
- Active case finding
Passive Surveillance
- Diseases are reported by health care providers
- Simple and inexpensive
- Incomplete and variable data quality
Sentinel Surveillance
- Reporting of health events by health professionals who are selected to represent a geographic area or specific reporting group
- Can be active or passive
Syndromic Surveillance
- Focuses on one or more symptoms rather than a physician-diagnosed or laboratory-confirmed disease
Surveillance Systems Attributes
- Usefulness - Does this system accomplish its objectives?
- Data quality - How reliable is the available data? How complete is it?
- Timelines - How quickly is information recieved?
- Simplicity - How easy is the system?