Vaccination drives hold out the promise of curbing Covid-19, but governments and businesses are increasingly accepting what epidemiologists have long warned: The pathogen will circulate for years, or even decades, leaving society to coexist with Covid-19 much as it does with other endemic diseases like flu, measles, and HIV.

The ease with which the coronavirus spreads, the emergence of new strains and poor access to vaccines in large parts of the world mean Covid-19 could shift from a pandemic disease to an endemic one, implying lasting modifications to personal and societal behavior, epidemiologists say.