COVID-19 updates: Elizabeth Warren tests positive
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.
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Hospitals stretched thin in Wisconsin, Michigan
In Wisconsin, only 4% of ICU beds are available.
"This is getting really scary," Dr. Jamie Hess, an emergency physician at the University of Wisconsin, told ABC News.
"We're really reaching a crisis point where we have more patients to take care of then we have beds in the hospital or staff to care for them," Hess said.
Michigan has been struggling through a similar surge for nearly three months, with the state reporting more than 6,500 new cases each day. On average, more than 500 patients are being admitted to hospitals each day.
"Where we are right now feels a lot like the first surge back in March of 2020," Erin Dicks, a nurse manager at MICU Henry Ford Hospital, told ABC News. "We don't have enough beds to be able to manage this."
Dicks said so many patients are young.
"I think one of the biggest frustrating pieces for my staff is that they look at this as, this is preventable -- people don't have to die here," Dicks said.
-ABC News' Arielle Mitropoulos
Harvard joins list of universities mandating boosters
Harvard University will require boosters for all eligible members of the community, school officials said Thursday.
Earlier this week, Harvard warned of an increase in cases, saying the rise can be attributed to social events following the Thanksgiving break.
Omicron is likely already on campus, university officials added.
Harvard joins a growing list of colleges and universities moving to require third doses next semester for those eligible. Other schools include Stanford, NYU, University of Notre Dame, Syracuse, Smith College and Wellesley College.
-ABC News' Arielle Mitropoulos
Illinois reports highest case number of the year
In Illinois, 11,858 new cases were reported on Thursday -- the highest daily case number of all of 2021, ABC Chicago station WLS reported, citing state health officials.
Illinois confirmed its second omicron case Wednesday, detected in a suburban Chicago resident. That person is asymptomatic and vaccinated, WLS reported.
CDC recommends opting for Pfizer or Moderna over J&J when there's a choice
The Centers for Disease Control and Prevention has signed off on its advisory committee's recommendation that people who have a choice should get an mRNA vaccine, either Pfizer or Moderna, over the single-shot Johnson & Johnson vaccine.
The updated recommendation comes after a review of new CDC data on rare blood clots linked to the J&J vaccine.
"Today's updated recommendation emphasizes CDC's commitment to provide real-time scientific information to the American public," CDC Director Dr. Rochelle Walensky said in a statement. "I continue to encourage all Americans to get vaccinated and boosted."
Omicron could spread up to 3 times faster than delta, new analysis finds
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