The senator says she's experiencing "mild symptoms."
As the COVID-19 pandemic has swept the globe, more than 5.3 million people have died from the disease worldwide, including over 806,000 Americans, according to real-time data compiled by Johns Hopkins University's Center for Systems Science and Engineering.
About 61.4% of the population in the United States is fully vaccinated against COVID-19, according to data from the Centers for Disease Control and Prevention.
An additional 10,059 confirmed cases of the omicron variant of COVID-19 have been reported across the U.K., according to the U.K. Health Security Agency's daily omicron overview on Saturday.
Confirmed omicron cases in the U.K. now total 24,968.
-ABC News' Rashid Haddou
A federal appeals court reinstated the Biden administration's nationwide workplace vaccine mandate Friday.
The Sixth Circuit Court of Appeals dissolved the stay issued by the Fifth Circuit last month on the rule, which would require employees at private companies with over 100 workers to get vaccinated or tested regularly.
The mandate "is an important step in curtailing the transmission of a deadly virus that has killed over 800,000 people in the United States, brought our healthcare system to its knees, forced businesses to shut down for months on end, and cost hundreds of thousands of workers their jobs," Judge Jane Stranch wrote in the opinion.
The rule, which was set to go into effect on Jan. 4, 2022, had been put on hold by the Fifth Circuit after it ruled that the Labor Department’s Occupational Safety and Health Administration didn’t have the legal authority to impose such a requirement on private businesses.
The Labor Department had previously said it won’t move forward with enforcing its workplace mandate until the matter was resolved in court.
Arkansas Attorney General Leslie Rutledge said Friday she plans to ask the U.S. Supreme Court to block the order.
-ABC News' Benjamin Siu and Anne Flaherty
The omicron variant could spread two to three times faster than delta, according to a new report from the Imperial College London COVID-19 response team.
The study, which has not yet been peer-reviewed, also estimated that the risk of being reinfected with omicron is more than five times higher than that of delta.
Data could change as more information on omicron's spread is gathered, though the study offers an early indication of how much more transmissible the new variant is compared to delta.
-ABC News' Cheyenne Haslett, Dr. John Brownstein and Sony Salzman
Due to a "substantial increase in cases across the league," the NFL announced that several weekend games have been pushed back.
Saturday's game between the Las Vegas Raiders and Cleveland Browns has been moved from Saturday to Monday.
The Washington Football Team vs. Philadelphia Eagles matchup and Seattle Seahawks-Los Angeles Rams game have both been moved from Sunday to Tuesday.
