COVID updates: Secretary of Defense Lloyd Austin tests positive
He said he has mild symptoms and will be quarantining for five days.
As the COVID-19 pandemic has swept the globe, more than 5.4 million people have died from the disease worldwide, including over 825,000 Americans, according to real-time data compiled by Johns Hopkins University's Center for Systems Science and Engineering.
About 62% of the population in the United States is fully vaccinated against COVID-19, according to data from the Centers for Disease Control and Prevention.
Latest headlines:
UCLA pulls out of bowl game
UCLA said its football team has pulled out of Tuesday night's San Diego County Credit Union Holiday Bowl due to COVID-19.
UCLA was set to play North Carolina State.
-ABC News' Matt Fuhrman
Greece sees record single-day increase
Greece reported 21,657 new COVID-19 cases on Tuesday -- a record 133% increase from the 9,284 new cases reported on Monday, according to government data.
Eighty-five percent of COVID-19 patients in Greece's hospitals are not vaccinated.
-ABC News' Christine Theodorou
US cases, hospitalizations, deaths expected to rise
Forecast models used by the CDC suggest cases, hospitalizations and deaths will rise over the next four weeks.
According to the models, the U.S. death toll could reach 862,900 by Jan. 22.
Nationally, estimates suggest between 8,700 and 20,800 Americans could be admitted to the hospital each day by Jan. 10.
These forecasts are from the COVID-19 Forecast Hub at UMass Amherst, where a team monitors and combines forecasting models from the nation’s top researchers. The team then creates an ensemble -- displayed like a hurricane forecast spaghetti plot -- usually with a wide cone of uncertainty.
-ABC News' Arielle Mitropoulos, Brian Hartman
Hugh Jackman tests positive, The Music Man cancels performances
Hugh Jackman, who has been starring in The Music Man on Broadway, tweeted that he tested positive for COVID-19 Tuesday morning.
"My symptoms are like a cold -- I have a scratchy throat and a bit of a runny nose," Jackman said in an Instagram video. "But I'm fine and I'm just going to do everything I can to get better ASAP. And as soon as I'm cleared, I'll be back on stage."
The Music Man tweeted that all performances are canceled through Jan. 1 and that Jackman will be back in the show on Jan. 6.
FDA and NIH studying why omicron variant may affect rapid tests
The U.S. Food and Drug Administration (FDA) says "studies are underway" examining why the omicron variant may make rapid COVID tests less effective.
Stephanie Caccomo, a spokeswoman for the FDA, told ABC News the agency will collaborate with the National Health Institute's (NIH) Rapid Acceleration of Diagnostics (RADx) program and select a variety of rapid tests to study.
However, Dr. Bruce Tromberg of the NIH -- who is leading these studies -- said Americans shouldn't be discouraged from using rapid tests.
Tromberg told ABC's Dr. Mark Abdelmalek that rapid tests are "extremely powerful and effective" at identifying people who are infected, with COVID which prevents them from spreading the virus.
"I have confidence that the tests that we have on our shelves can pick up omicron," Tromberg added.
Testing companies also stressed that their tests still work to detect omicron, with Abbott saying Tuesday that the company has tested the popular BinaxNOW rapid test and found "equivalent sensitivity" compared to prior variants.
-ABC News' Sony Salzman