Pandemic

 

A pandemic is a epidemic of an infectious disease that has spread across a large region, for instance multiple continents or worldwide, affecting a substantial number of people. A widespread endemic disease with a stable number of infected people is not a pandemic. Widespread endemic diseases with a stable number of infected people such as recurrences of seasonal influenza are generally excluded as they occur simultaneously in large regions of the globe rather than being spread worldwide. 

Throughout human history, there have been a number of pandemics of diseases such as smallpox and tuberculosis. The most fatal pandemic in recorded history was the Black Death (also known as The Plague), which killed an estimated 75-200 million people in the 14th century. The term was not used yet but was for later pandemics including the 1918 incluenza pandemic (Spanish flu). Current pandemics include COVID-19 (SARS-CoV-2) and HIV/AIDS.

A pandemic is an epidemic ocurring on a scale that crosses international boundaries, usually affecting people on a worldwide scale. A disease or condition is not a pandemic merely because it is widespread or kills many people; it must also be infectious. For instance, cancer is responsible for many deaths but is not considerer a pandemic because the disease is neither infectious nor contagious.