It’s a rare development in the campaign to blunt the deadly effects of the Covid-19 coronavirus: some good news from the scientists.

“The coronavirus is here to stay, but once most adults are immune — following natural infection or vaccination — the virus will be no more of a threat than the common cold,” affecting mostly children, reports the New York Times, citing a study published in the journal Science.

“The virus is a grim menace now because it is an unfamiliar pathogen that can overwhelm the adult immune system, which has not been trained to fight it,” the Times says. “That will no longer be the case once everyone has been exposed to either the virus or vaccine.”

Young children are better at fending off most pathogens, including the coronavirus, compared with grownups and teenagers.

“Eventually, the study suggests, the virus will be of concern only in children younger than 5, subjecting even them to mere sniffles — or no symptoms at all,” the Times says, adding that the virus will become “endemic,” a pathogen that circulates at low levels and only rarely causes serious illness.

So really, the name of the game is getting everyone exposed for the first time to the vaccine as quickly as possible,” says the leader of the study, Dr. Jennie Lavine of Emory University.

Lavine and her colleagues looked to the six other human coronaviruses including four that cause the common cold, which are endemic and produce mild symptoms, and which researchers believe closely resemble the Covid-19 virus.

The biggest question: how long will it take for the Covid virus to become endemic? The answer: longer than we’d like.

“Depending on how fast the virus spreads, and on the strength and longevity of the immune response, it would take a few years to decades of natural infections for the coronavirus to become endemic,” Dr. Lavine told the Times.