Unawareness about these words, leads to many people using them completely incorrectly; interchangeably. The difference, although, is about their scale or spread. So, let’s explore these.
Outbreak: In epidemiology, an Outbreak is a sudden increase in occurrences of a disease in a particular time and place. It may affect a small and localized group or impact upon thousands of people across an entire continent .ie. The extent has limited geographic area. Four linked cases of a rare infectious disease may be sufficient to constitute an outbreak.
Epidemic: Occasionally, the amount of disease in a community rises above the expected level. Epidemic refers to an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area. Outbreak carries the same definition of epidemic, but is often used for a more limited geographic area.
Pandemic: Pandemic refers to an epidemic that has spread over several countries or continents, usually affecting a large number of people.