"I'm going to upset some people on this, but I think we should," Fauci said during a MSNBC interview in answer to a question about requiring teachers to be vaccinated.
"I mean, we are in a critical situation now," he said. "We've had 615,000-plus deaths, and we are in a major surge now as we're going into the fall, into the school season. This is very serious business."
Despite warnings from President Biden that the U.S. could see increased mandates with the rise in delta variant-positive cases, Fauci said the directives will not come from the federal level.
The director of the National Institute of Allergy and Infectious Diseases said the orders would come from state leaders instead.
Fauci suggested he thinks statewide mandates will become increasingly likely after the Food and Drug Administration gives its stamp of approval to the vaccine.
Biden said the vaccine’s FDA approval is expected sometime this fall, though the administration has yet to home in more precisely on when the U.S. can expect the federal green light.
"There's no doubt that these vaccines are going to get fully approved," Fauci said. "This idea about, 'It's not fully approved,' is really a false narrative. It really is. I mean, you should consider this as good as fully approved and get vaccinated."
Children ages two through 12 have not been approved to receive the coronavirus vaccine – a hurdle that has become ever more urgent with the more contagious delta variant.
The number of reported cases of children contracting the virus increased by four percent last week according to data from the American Academy of Pediatrics with nearly 94,000 newly confirmed cases.
Fauci said he thinks it is necessary for children and adults to don masks while at school.
"It's not comfortable, obviously, for children to wear masks, particularly the younger children," he told conservative radio host Hugh Hewitt Monday. "This virus not only is so extraordinarily transmissible, but we're starting to see pediatric hospitals get more and more younger people and kids not only numerically, but what seems to be more severe disease."
Parents who oppose their kids wearing masks argue it is impeding their social and cognitive abilities because masks hide an individual’s expression.
Fauci said the Centers for Disease and Prevention (CDC) were attempting to "balance" the potential threat delta poses to children and adults.
"But hopefully, this will be a temporary thing, temporary enough that it doesn't have any lasting negative impact on them," he added.
The CDC reported a daily average of nearly 90,000 new cases last week, a near 34 percent increase from the week prior.
Jessica Chasmar contributed to this report.