Pandemic
A pandemic (/pænˈdɛmɪk/ pan-DEM-ik) is an epidemic of an infectious disease that has spread across a large region, for instance multiple continents or worldwide, affecting a substantial number of individuals.
Widespread endemic diseases with a stable number of infected individuals 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.
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.[2][3][4][5]
The term had not been used then but was used for later epidemics, including the 1918 influenza pandemic—more commonly known as the Spanish flu.[6][7][8] T
he most recent pandemics include the HIV/AIDS pandemic,[a][9] the 2009 H1N1 pandemic and the COVID-19 pandemic.
Almost all these diseases still circulate among humans though their impact now is far less.