Dr. Anthony S. Fauci, President Biden’s chief medical adviser for Covid-19, said on Sunday that Americans may still be wearing masks outside their homes a year from now, even as he predicted the country would return to “a significant degree of normality” by fall.

“I want it to keep going down to a baseline that’s so low there is virtually no threat,” Dr. Fauci said on the CNN program “State of the Union,” referring to the number of cases nationally that would make him comfortable enough to stop recommending universal masking. “If you combine getting most of the people in the country vaccinated with getting the level of virus in the community very, very low, then I believe you’re going to be able to say, for the most part, we don’t necessarily have to wear masks.”