As bad as the coronavirus has been already, it could come back again in the future, and doctors are working to make sure a vaccine is in place if and when it does.

What was normal just weeks ago has been flipped on its head, with schools closed and non-essential employees being required to stay home. It's left everyone asking -- when will this be over, and could it happen again?

White House Health Adviser Dr. Anthony Fauci says this could all come back once again.

"I think it's more probable than not that this virus will come back again next season," says Fauci.

This isn't surprising to most doctors, because there are already four other strains of the coronavirus that have appeared seasonally.

Dr. Bettina Fries is the chief of infectious diseases at Stony Brook Medicine. She says researchers worldwide are working nonstop to find a vaccine.

"The hope is we will share this knowledge internationally and we will make a vaccine that will protect, literally, the world," says Fries. "And once we have that vaccine, then even if this virus comes back every season, we're going to be prepared. The reason why this has been such an ordeal this season is because we all do not have immunity."

Doctors say what is still unknown is whether patients who are recovering from COVID-19 will have any lasting natural immunity, and how long a vaccine will last.

In the meantime, Fries is warning everyone to stay home and separate.

"Unfortunately, we still see an increase of admissions so we're not there yet," she says. "We have not flattened our curve yet."