A pandemic 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 people.
The most fatal pandemic in recorded history was the Black Death , which killed an estimated 75200 million people in the 14th century. The term was not used yet but was for later pandemics including the 1918 influenza pandemic . Current pandemics include COVID-19 and HIV/AIDS.
