In a conversation with the Journal of the American Medical Association on Wednesday, Fauci said many of the COVID-19 infections are happening in small gatherings of family and friends.
And as people make their holiday plans, he asked them to consider the following:
"Six, eight, 10 people come together in someone's home. You have one person who is asymptomatic and infected and then all of a sudden four or five people are infected," he said. "To me, that's the exact scenario that you're going to see on Thanksgiving."
COVID-19: Dr. Fauci reveals when he thinks life will return to normal
Fauci said we need to have 90 to 95% of the population wearing masks, following the successful mask strategies of other nations. He said in countries like New Zealand and Australia, new infections continue to be sparse.
"If you don't want to shut down, at least do the fundamental basic things which are really the flagship of wearing a mask. And that's what we really have to do. We can't have this very inconsistent wearing," he said.
As for the concept of herd immunity, which the White House has embraced, Fauci some skepticism.
"No one really knows what herd immunity is for this disease, but let's assume it's around 70% or so. You know how many deaths you're going to have before you get there?" he said. "That's an unacceptable pathway. We get to herd immunity with a vaccine. That's how you get to herd immunity."
As for a vaccine, Dr. Fauci said he is confident in Operation Warp Speed's plan for widespread distribution plan, but he doesn't expect any vaccine makers to apply for an emergency use authorization until December.