In epidemiology, endemic refers to the circulation of a disease within a certain population or geographic area that continues without outside interference or introduction. Once a disease has been eliminated from a geographic region, such as a continent, it is no longer endemic to that region.
When an infectious disease is endemic, it means that the disease is constantly circulating in a population, but cases are neither rising nor falling. Malaria, for example, is endemic in many African, South American, and South Asian countries, and kills around 600,000 people a year.
Scientists expect the virus SARS-CoV-2 to become endemic, meaning it will always be circulating like influenza and cold viruses. What scientists don’t know is whether COVID-19 disease (caused by SARS-CoV-2) will become less prevalent and deadly or whether the virus will continually mutate to develop variants that evade vaccines and cause large waves in cases as well as disease.
There has been a misperception that as this pandemic has moved to an endemic phase and Americans no longer have to worry about COVID-19. That is not the case. It may be that we will be dealing with returning mask mandates and booster vaccine shots for many years to come, if there are repeated large waves of cases.