At the first White House task force briefing in two months, Dr Fauci said: "The only way we're going to end it is by ending it together."
As health experts said more must be done to slow the spread, Vice-President Mike Pence praised US "progress".
More than 40,000 new cases were recorded across the US on Friday
The total of 40,173, given by Johns Hopkins University, was the highest daily total so far, exceeding the record set only the previous day.
There are over 2.4 million confirmed infections and more than 125,000 deaths nationwide - more than any other country.
During Friday's briefing, the White House task force also urged millennials to get tested, even if they are asymptomatic.
Mr Pence said the president requested the task force address the American people amid surges in infections and hospital admissions across southern and western states.
In Texas, Florida and Arizona, reopening plans have been paused due to the spike.
While some of the increase in daily cases recorded can be attributed to expanded testing, the rate of positive tests in some areas is also increasing.
Health officials in the US estimate the true number of cases is likely to be 10 times higher than the reported figure.