Mr Fauci, along with several other US health officials, testified before Congress Tuesday.
According to Mr Fauci, if the US doesn't curb the surge in new virus cases, the number of infected individuals could rise to 100,000 a day. Mr Fauci claimed the spike in areas of the country like the South and the West are putting the "entire country at risk."
"We are now having 40-plus thousand new cases a day. I would not be surprised if we go up to 100,000 a day if this does not turn around," Mr Fauci said. "And so I am very concerned."
Dr Robert Redfield, the director of the Centers for Disease Control and Prevention, also shared testimony during the hearing.
Mr Redfield said the agency was busy preparing a public education blitz to build confidence in the US public for an eventual coronavirus vaccine.
The health officials claimed they needed the program to build "vaccine confidence" among those who view the government and vaccines with scepticism.
"I think it's very important that we have an integrated plan for this vaccine," Mr Redfield said.
According to Mr Fauci, the education program will be implemented at vaccine trial sites.
"It is a reality: a lack of trust of authority, a lack of trust in government, and a concern about vaccines in general," Mr Fauci said.
Mr Fauci noted it was not just anti-vaxxers who were sceptical of the government; he warned that on-the-ground community engagement would be necessary to earn the trust of poor and minority communities where people have "not always been treated fairly by the government."
Dr Stephen M Hahn, the commissioner of the Food and Drug Administration, pressed the importance of the public's confidence in any forthcoming vaccines.
"Public confidence in vaccines is so important. We have an obligation to use all of our scientific knowledge, regulatory framework to ensure that any vaccine that comes before us, whether for authorization or approval, meets our stringent standards for safety and effectiveness," Mr Hahn said.
Vaccines are being developed under President Donald Trump's "Operation Warp Speed," an accelerated production program aiming to have at least 300 million doses of a vaccine ready by the beginning of 2021.
The FDA has worked to counter public fears that the accelerated vaccine development process might result in a more dangerous or less-tested treatment.