COVID-19 updates: Elizabeth Warren tests positive

The senator says she's experiencing "mild symptoms."

Last Updated: December 20, 2021, 12:51 AM EST

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.

Latest headlines:

Here's how the news is developing. All times Eastern.
Dec 15, 2021, 1:57 PM EST

Fenway Park to reopen as booster site

Boston's historic baseball stadium Fenway Park, which transformed into a mass vaccination site last winter, is expected to reopen its doors as a booster shot location in January, Red Sox officials told ABC News.

The Red Sox are working with the city and the governor's office to finalize the plans, Red Sox spokeswoman Zineb Curran said.

People check in to receive a dose of the Pfizer BioNtech COVID-19 vaccine at a mass vaccination site at Fenway Park in Boston, Jan. 29, 2021.
Bloomberg via Getty Images, FILE

People 75 years old and older wait in line for their COVID-19 vaccinations inside Fenway Park in Boston, Feb. 1, 2021.
Boston Globe via Getty Images, FILE

-ABC News' Arielle Mitropoulos

Dec 15, 2021, 1:17 PM EST

Fauci says if we didn't have the tools, he'd be way more worried about omicron

Asked how worried Americans should be about omicron and a post-holiday surge, Dr. Anthony Fauci said that if we didn't have vaccines, boosters and masks he'd "really be worried." 

"But we have tools. So get vaccinated, get boosted," Fauci said at Wednesday's White House COVID-19 briefing.

CDC Director Rochelle Walensky said the agency expects to see omicron continue to grow.

"What does this mean for individuals and families as we head into the winter months? A time when families may be gathering with one another over the holidays? It means that it is vital for everyone to get vaccinated and boosted if they are eligible," Walensky said. 

A pharmacy in Grand Central Terminal advertises the COVID-19 vaccine, Dec. 9, 2021, in New York.
Spencer Platt/Getty Images

White House COVID-19 response coordinator Jeff Zients added, "We're not going to shut down our economy in any way. We're going to keep our schools and our businesses open."

-ABC News' Cheyenne Haslett

Dec 15, 2021, 12:42 PM EST

UK sees highest number of cases since start of pandemic

The United Kingdom confirmed 78,610 COVID-19 cases in the last 24 hours -- the highest daily number since the start of the pandemic, officials said Wednesday.

A covid testing centre sign at Heathrow Terminal 2, Nov.28, 2021, in London.
Hollie Adams/Getty Images

Prime Minister Boris Johnson encouraged everyone to continue to get vaccinated and boosted. He said 650,000 boosters were administered Tuesday and now 45% of all adults have received a booster.

-ABC News' Joe Simonetti

Dec 15, 2021, 11:39 AM EST

NYU and Princeton move to cancel end-of-year events, hold exams online

School leaders at both New York University and Princeton University announced Wednesday that they will take steps to cancel end-of-year events and move winter exams online amid a surge in COVID-19 cases on their respective campuses.

"Given that we've seen an uptick in cases among undergraduates during the last 24 hours -- including suspected cases of the highly contagious Omicron variant -- we hope to avoid letting the final exam schedule interfere with students’ travel home for Winter Break," Princeton University's dean, Jill Dolan, and vice president for campus life, Rochelle Calhoun, said in a joint statement. "We certainly don’t want you remaining on campus in required isolation through the holidays."

All indoor gatherings with food and those where face coverings cannot be worn must be canceled or postponed at Princeton's New Jersey campus from Thursday through Jan. 7, according to the statement.

People walk on campus at Princeton University, Feb. 4, 2020 in Princeton, N.J.
William Thomas Cain/Getty Images, FILE

A statement from New York University's provost, Katherine Fleming, executive Vice President, Martin Dorph, and head of the COVID-19 prevention and response team, Dr. Carlo Ciotoli, said they "strongly encourage that final examinations and/or assessments be changed to remote/online format." All discretionary, non-essential, non-academic gatherings and events at the school's campus in New York City must be canceled "immediately," according to the statement.

"The continuous review of the data from our COVID-19 testing program has indicated a considerable acceleration in the rate of new cases in our community," they said. "It’s not a cause for alarm, but it is a cause for concern, caution, and appropriate actions."

NYU has also joined a growing list of colleges and universities across the nation that are requiring all eligible members of the school community, including faculty and students, to be fully vaccinated against COVID-19 and receive a booster shot ahead of the upcoming spring semester.

A New York University flag flies outside of the NYU business school, Aug. 25, 2020, in New York City.
Spencer Platt/Getty Images

Meanwhile, officials at Cornell University in Ithaca, New York, announced Tuesday that they have moved the campus into a "level red" alert after identifying evidence of suspected cases of the omicron variant in a "significant" number of the school's COVID-19 positive samples from students.

According to data from the Centers for Disease Control and Prevention, the omicron variant is estimated to account for more than 13% of newly confirmed COVID-19 cases in the New York and New Jersey area -- the highest proportion of any region of the United States.

-ABC News' Chris Donato and Arielle Mitropoulos