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.

“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. Meanwhile, a new and potentially lucrative Covid-19 industry is emerging quickly, as businesses invest in goods and services such as air-quality monitoring, filters, diagnostic kits and new treatments.

A person slept outdoors to save a spot in line for a limited number of oxygen-tank refills during a Covid-19 outbreak in Peru last week.

The number of gene-detecting PCR tests produced globally is expected to grow this year, with manufacturers like New Jersey’s Quest Diagnostics Inc. predicting that millions of people will need a swab before they attend concerts, basketball games or family functions.

“We assume it would last for years, or be eternal, such as the flu,” said Jiwon Lim, spokesman for South Korea’s SD Biosensor, Inc., a test maker that is ramping up production of at-home diagnostic kits. Leading drug makers—Switzerland’s Novartis International AG and Eli Lilly & Co.—have invested in potential Covid-19 therapies. More than 300 such products are currently in development.