The National Football League is closing all team facilities to in-person activities on Monday and Tuesday.

The ban doesn't apply to teams scheduled to play on those days, including a Steelers-Ravens game on Tuesday that's already been rescheduled twice.

The NFL cited in a league-wide memo rising COVID-19 cases in the U.S. and the "understanding that a number of players and staff celebrated the Thanksgiving holiday with out-of-town guests" as reasons for the closures.

ABC News' Kelsey Walsh contributed to this report.

Public and private gatherings with those outside your household will be prohibited in Los Angeles County starting Monday under a new public health order.

Playgrounds and cardrooms will also close, among other restrictions.

Religious gatherings and protests are exempt from the temporary order, which will remain in effect through Dec. 20.

The measures come as the county continues to see "alarming levels" of new COVID-19 cases and increasing hospitalizations, the Los Angeles County Department of Public Health said.

As of Wednesday, outdoor dining in the county is on pause for the next three weeks.

Officials had warned additional lockdown measures would come once the five-day average of cases reached 4,500. On Friday, that number was 4,751.

ABC News' Matthew Fuhrman and Bonnie Mclean contributed to this report

More than 13 million people have tested positive for COVID-19 in the U.S., according to Johns Hopkins University.

The U.S. crossed 12 million cases six days ago.

Experts have cautioned against reading too much into data reported before next week, as some state updates may be spotty due to the Thanksgiving holiday.

Vermont officials are urging people who had Thanksgiving gatherings with those outside their household to now quarantine.

“My request to Vermonters who may have participated in travel and/or multi-household gatherings is simply this: Please quarantine yourselves at home, and please get tested now and in seven days,” state Health Commissioner Dr. Mark Levine said during a press briefing Friday.

Gov. Phil Scott echoed the health commissioner’s request.

“If you have had one of those gatherings yesterday, then you shouldn't send your kids to school next week," he said. "You should quarantine your kids for at least seven days, get a test, and then we'll move forward."

Scott said earlier in the week that school officials will ask returning students if they attended a Thanksgiving gathering with people outside their household to determine quarantine requirements.

"We did all of this to try and protect Vermont, to try and prevent the rise in the number of cases," Scott said Friday.

ABC News' Joshua Hoyos contributed to this report

The actual number of people infected with the novel coronavirus in the United States reached nearly 53 million at the end of September, according to a model developed by scientists at the Centers for Disease Control and Prevention.

The scientists estimated the cumulative incidence of COVID-19 in the U.S. population by taking the laboratory-confirmed case counts that were reported nationally and adjusting them for sources of under-detection based on testing practices in inpatient and outpatient settings. Preliminary estimates using the model found that 2.4 million hospitalizations, 44.8 million symptomatic illnesses and 52.9 million total infections may have occurred through Sept. 30.

"This indicates that approximately 84% of the U.S. population has not yet been infected and thus most of the country remains at risk, despite already high rates of hospitalization," the scientists wrote in a report published in the Nov. 25 issue of the journal Clinical Infectious Diseases.

There were 6.9 million laboratory-confirmed cases of of domestically-acquired infections that were detected and reported nationally through Sept. 30. Since then, the CDC's tally has increased to nearly 12.5 million. Based on the model's ratio, the true estimated total would now be more than 95 million.