Here's how the news is developing. All times Eastern.
Dec 14, 2021, 2:52 PM EST
Omicron will 'for sure' become dominant strain in US: Fauci
Dr. Anthony Fauci told CNN Tuesday that omicron will "for sure" become the dominant strain in the U.S. given how rapidly it is spreading.
"Omicron is going to be a challenge because it spreads very rapidly," Fauci said.
Fauci reiterated that omicron so far appears to be less severe, adding, "Whether it is inherently less pathogenic as a virus or whether there is more protection in the community, we're just going to have to see when it comes in the United States."
-ABC News' Arielle Mitropoulos
Dec 14, 2021, 2:21 PM EST
Cornell moves exams online due to 'substantial' number of suspected omicron cases
Cornell University is moving into a "level red" alert after a "significant" number of suspected omicron cases were detected among student samples.
Mennen Hall and Campus, Cornell University, Ithaca, New York.
Education Images/Universal Images Group via Getty Images, FILE
"While we must await confirmatory sequencing information to be sure that the source is Omicron, we are proceeding as if it is," university president Martha Pollack wrote in a letter to the community.
All final exams will be online beginning Tuesday, Pollack announced, and libraries and fitness centers are closed.
All undergraduate events are canceled, as is Saturday's recognition ceremony for December graduates, Pollack said.
Cornell has recorded more than 600 confirmed cases among students and staff in the last week alone, according to the university dashboard. While no infected students are seriously sick, Pollack said the university has "a role to play in reducing the spread."
-ABC News' Arielle Mitropoulos, Chris Donato
Dec 14, 2021, 12:34 PM EST
Omicron 'spreading at a rate we have not seen,' WHO says
"Omicron is spreading at a rate we have not seen with any previous variant," World Health Organization Director-General Dr. Tedros Adhanom Ghebreyesus warned Tuesday.
Omicron has been reported in 77 countries, he said, adding that the new variant is likely in most countries.
People wait to be vaccinated by a member of the Western Cape Metro EMS (Emergency Medical Services) at a mobile "Vaxi Taxi" which is an ambulance converted into a mobile COVID-19 vaccination site in Blackheath in Cape Town, South Africa, Dec. 14, 2021.
Nardus Engelbrecht/AP
People queue at Westminster Bridge to receive COVID-19 vaccine and booster doses, as the spread of the coronavirus disease (COVID-19) continues, at a walk-in vaccination centre at Saint Thomas' Hospital in London, Britain, Dec. 14, 2021.
Toby Melville/Reuters
Tedros said health officials are "concerned that people are dismissing omicron as mild."
"Even if omicron does cause less severe disease, the sheer number of cases could once again overwhelm unprepared health systems," he said.
-ABC News' Christine Theodorou
Dec 14, 2021, 11:41 AM EST
England to lift travel ban on southern African nations
British Transport Secretary Grant Schapps announced Tuesday that England will remove all southern African nations from its travel red list.
After the omicron variant was first discovered in South Africa and Botswana in November, several countries around the world, including England and the United States, imposed travel bans on a swath of nations in southern Africa.
The World Health Organization warned that blanket travel bans will not prevent the international spread of omicron, deemed a "variant of concern," and that restrictions place a heavy burden on lives and livelihoods.
Passengers walk through the international arrivals area at Terminal 5 at Heathrow Airport in London, England, on Nov. 26, 2021.
Leon Neal/Getty Images, File
The countries of Angola, Botswana, Eswatini, Lesotho, Malawi, Mozambique, Namibia, Nigeria, South Africa, Zambia and Zimbabwe will be taken off England's travel red list on Wednesday at 4 a.m. GMT, according to Schapps, who noted that all current testing measures remain in place.
"As always, we keep all our travel measures under review and we may impose new restrictions should there be a need to do so to protect public health," Schapps wrote on Twitter Tuesday.
Despite the travel bans, the heavily mutated variant has taken a foothold in London. British Health Secretary Sajid Javid told Parliament on Monday that omicron accounts for more than 44% of COVID-19 infections in the U.K. capital and it's expected to become the dominant variant there by Wednesday, overtaking the highly contagious delta variant.
Addressing Parliament again on Tuesday, the health secretary called omicron "a grave threat" and said the "race" to get as many people vaccinated and boosted "is new national mission."
"Scientists have never seen a COVID-19 variant that’s capable of spreading so rapidly," Javid said.