The coronavirus is here to stay, but it won't be as deadly in the future, scientists say

With the one-year anniversary of the COVID-19 pandemic on the horizon, vaccinations are escalating in the United States. More than 28 million Americans have been infected and likely have developed some form of natural immunity. 

So what does the future hold for the coronavirus?  

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Many scientists expect the coronavirus will stick around indefinitely, but they also believe the illness it causes will become far less serious. 

Erica Ollman, a professor at the La Jolla Institute for Immunology in San Diego, told CNBC that the coronavirus likely will become "a permanent part of the human existence."

She's not alone in that thinking. 

A recent survey of more than 100 immunologists, virologists and infectious disease experts found nearly 90% of them believed the coronavirus will become endemic. The term is used to describe illnesses that are constantly circulating — like influenza and the common cold. 

John Brownstein, an epidemiologist at Harvard Medical school, told ABC News that the coronavirus isn't going anywhere. 

"This coronavirus is going to be here to stay," Brownstein said. "Eradication of this new coronavirus is basically impossible."

But as more adults develop immunity to COVID-19 through infections or vaccinations, the coronavirus primarily will spread among children, who tend to develop less severe symptoms, according to a modeling study published last month by Science. 

Eventually, COVID-19 would be no more virulent than the common cold, the researchers said. 

That's partly because reinfections, in general, tend to be less severe, according to scientists. Still, people with underlying medical conditions may still have severe responses, just like the flu can prove deadly among vulnerable populations. 

Dr. Paul Offit, a professor of pediatrics in the Division of Infectious Diseases at the Children's Hospital of Philadelphia, told ABC News that the coronavirus eventually "will cause fewer deaths than influenza." 

Tens of thousand of U.S. residents die of the flu each year. But that's nowhere near the death toll of COVID-19, which has killed more than 515,000 Americans in about a year. 

But getting to an endemic phase will not happen all at once, according to Jennie Lavine, a postdoctural fellow at Emory University who helped lead the modeling study. 

"The timing of how long it takes to get to this sort of endemic state depends on how quickly the disease is spreading, and how quickly vaccination is rolled out," Lavine told the New York Times.

Dr. Anthony Fauci, who heads the National Institute of Allergy and Infectious Disease, has said Americans likely will be waring masks in 2022.  

The World Health Organization issued a similar message earlier this week. 

Dr. Michael Ryan, the director of WHO's emergencies program, said it's "premature" and "unrealistic" to think the coronavirus pandemic will be over by the end of the year. He said the speed of vaccinations are key to ending the crisis. 

"If we’re smart, we can finish with the hospitalizations and the deaths and the tragedy associated with this pandemic," Ryan said.