The director of the National Institute of Allergy and Infectious Diseases, speaking at the American Society of Tropical Medicine and Hygiene's annual meeting, said he doesn't expect that to change any time soon.
That's because the United States "never came down to [the] low baseline" seen in Europe over the summer, when that continent instituted strict virus control measures and encouraged widespread use of face coverings.
Many states nationally saw a "resurgence of cases" during the summer "due to attempts to quote-unquote reopen the country," he said as part of a special session during the annual meeting, which was held online because of the pandemic.
Research tracking cellphone GPS data among U.S. residents shows that people leaving the house to go to work or run errands did not decline as sharply as it did overseas, Fauci said.
Now, with cold weather arriving in many parts of the country, many areas are seeing new surges in cases, he noted.
Europe is approaching 200,000 new COVID-19 cases daily, with the United States not far behind, at more than 130,000 per day over the past week, despite having less than half of the total population of the continent, Fauci said.
Through Monday, the United States had more than 11 million confirmed cases, according to figures from Johns Hopkins University.
"We would not be having the degree of surge in cases we're seeing" if more people were wearing face coverings, practicing social distancing and avoiding large gatherings, Fauci said.
Even with positive news on new COVID-19 vaccines, "we will have more work to do" to bring about the end of the pandemic, according to Dr. Heidi Larson, director of the Vaccine Confidence Project at the London School of Hygiene and Tropical Medicine.
In a survey of U.S. adults, fewer than 40% said they would "definitely accept" a new vaccine against the virus, a figure that declined slightly after participants were shown widely circulating "misinformation" about the science behind the shots, she said.
These figures show that "trust in government and trust in the COVID response and how it's been managed will absolutely influence how public responds to vaccine," she said.