When will COVID-19 become ‘endemic’?

Over time, epidemics can become ‘endemics.’ An epidemic is when there is a higher number of cases than we would expect, and an endemic is when there is a stable number of infections in the population.
For COVID-19 we’re still learning what a baseline worldwide will look like, but it doesn’t seem likely that we can eradicate it, so endemicity is more likely the future for COVID-19.
The build-up of immunity due to vaccination and infection drives the transition from epidemic to endemic. When this happens, new COVID-19 infections will mostly be in those people that have had the virus before, are vaccinated or were born after COVID-19 began.
It’s possible that protection against severe disease due to prior infection and/or vaccination will be long-lasting. That means that COVID-19 would be fairly mild for most people, as early childhood infections also tend to be mild. Of course, viral evolution and the new variants could complicate this.