Incidence:
- The number of new cases of a disease in a population over a specific period of time.
Prevalence:
- The total number of cases of a disease in a given population at a specific point in time or over a specified period.
Outbreak:
- The occurrence of cases of a particular disease in a population, geographic area, or community that is greater than what is normally expected.
Endemic:
- The constant presence of a disease or infectious agent within a geographic area or population.
Pandemic:
- An epidemic that has spread over several countries or continents, affecting a large number of people.
Sensitivity:
- The ability of a test to correctly identify individuals with the disease or condition (true positive rate).
Specificity:
- The ability of a test to correctly identify individuals without the disease or condition (true negative rate).
Case-Control Study:
- An observational study where individuals with a specific condition (cases) are compared to individuals without the condition (controls) to identify factors associated with the disease.
Cohort Study:
- An observational study in which a group of individuals with a common characteristic (cohort) is followed over time to determine the incidence of a particular disease.
Herd Immunity:
- The indirect protection from infectious diseases that occurs when a large percentage of a population becomes immune, either through vaccination or previous infection, reducing the spread of the disease.