II. Definition
- Number of current cases per population at risk
- Old: Persistent active disease contracted previously
- New: Onset of active disease
- Point Prevalence
- Prevalence at a specific point in time
- Period Prevalence
- Prevalence over a given time interval
III. Usage
- Measure amount of illness in the community
- Determine health care needs of the community
IV. Contributing factors
- Disease Incidence Rate
- Illness Duration
V. References
- Hennekens (1987) Epidemiology Medicine, p.54-98