OUTBREAK, EPIDEMIC, PANDEMIC DEFINITIONS

Definitions

Outbreak

When a disease infects a lot of people in one area in a short period of time, that’s an outbreak.

Epidemic

The World Health Organization defines an epidemic as the occurrence in a community or region of cases of an illness ... clearly in excess of normal expectancy. The Center for Disease Control (CDC) defines it as an increase, often sudden, in the number of cases of a disease above what is normally expected in a region. By that definition, the coronavirus outbreak has certainly reached “epidemic” status in a number of regions, most notably China, South Korea, Iran, and Italy.

Pandemic

According to A Dictionary of Epidemiology, a pandemic is an epidemic occurring worldwide, or over a very wide area, crossing international boundaries and usually affecting a large number of people. Disease experts use the term “pandemic” to describe when an epidemic has become rampant in multiple countries and continents simultaneously. The WHO — the global body with authority to officially declare a pandemic defines pandemic loosely as “the worldwide spread of a new disease.” The U.S. Center for Disease Control and Prevention defines it this way: “Pandemic refers to an epidemic that has spread over several countries or continents, usually affecting a large number of people.”

Pandemics must be battled, at the international level, significantly differently than epidemics. When one region of the world experiences an epidemic, the rest of the world is on the sidelines. They may shut their borders to the affected region, or send help, or both. They may start making preparations in case the disease affects their own country. When there’s a global pandemic, there largely are no sidelines. It no longer makes sense for countries to shut their borders against the affected countries, as the disease is present everywhere. Public health officials might recommend shifting to social distancing measures — which reduce spread within a country — instead of screening efforts that try to keep the disease out of the country at all. Countries still must share medical knowledge and expertise with one another, but directing supplies to affected areas is more complicated when affected areas are everywhere. A world fighting a pandemic is not focused on containment to a distant elsewhere but on harm-reduction at home.