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.

“Going through the five phases of grief, we need to come to the acceptance phase that our lives are not going to be the same,” said Thomas Frieden, former director of the U.S. Centers for Disease Control and Prevention. “I don’t think the world has really absorbed the fact that these are long-term changes.”

Endemic Covid-19 doesn’t necessarily mean continuing coronavirus restrictions, infectious-disease experts said, largely because vaccines are so effective at preventing severe disease and slashing hospitalizations and deaths. Hospitalizations have already fallen 30% in Israel after it vaccinated a third of its population. Deaths there are expected to plummet in weeks ahead.

But some organizations are planning for a long-term future in which prevention methods such as masking, good ventilation and testing continue in some form.