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.
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'Nutcracker' performances canceled in NYC
The New York City Ballet has canceled the rest of its performances of "The Nutcracker" due to COVID-19 cases, ABC New York station WABC reported.
"The Nutcracker" was set to run through Sunday.
Why CDC doesn't require testing at end of isolation: Director
The newly updated CDC guidelines don't require testing at the end of isolation because PCR tests can stay positive for up to 12 weeks, CDC Director Dr. Rochelle Walensky told "Good Morning America" Wednesday.
"So we would have people in isolation for a very long time if we were relying on PCRs," Walensky said.
Walensky also addressed Tuesday's news from the FDA that, according to early data, rapid antigen tests may be less sensitive when it comes to the omicron variant.
"We do know that the most sensitive test you can do is a PCR test," Walensky said. "So if you have symptoms and you have a negative antigen test, we do ask you to go and get a PCR to make sure those symptoms are not attributable to COVID."
Walensky said rapid tests do work "quite well," especially in places where people are being tested regularly, like at schools.
"They may not work as well as they have for the delta variant," Walensky said, but "we still are encouraging their use."
Global COVID cases rose 11% last week, WHO says
New COVID-19 cases increased 11% last week over the week prior, The World Health Organization said on Tuesday.
Almost 5 million new infections were recorded in the week that ended Dec. 26, the agency said in its weekly epidemiological update. The rise followed a "gradual increase" since October, the agency said.
WHO officials said the risk from the omicron variant "remains very high."
The agency said early data from the United Kingdom, South Africa and Denmark suggested a reduced risk of hospitalization for those infected with omicron, but said "further data are needed to understand the clinical markers of severity including the use of oxygen, mechanical ventilation and death, and how severity may be impacted by vaccination and/or prior SARSCoV-2 infection."
San Francisco cancels New Year's Eve fireworks
San Francisco officials canceled the city's New Year's Eve fireworks show, citing concerns about the spread of the omicron variant.
"After closely monitoring local health indicators, the decision to cancel is a proactive measure that will best protect SF & essential front-line workers," the city's department of emergency management said in a statement on Tuesday.
About 84% of eligible residents are fully vaccinated and 55% have had a booster shot, according to city health data. But omicron still "poses a significant risk," officials said in a statement.
“While we are all understandably eager to ring in a new year with San Francisco’s customary New Year’s Eve fireworks show, we must remain vigilant in doing all we can to stop the spread of the COVID-19 Omicron variant,” Mayor London Breed said.
UK, Italy, Greece report record new daily cases
The United Kingdom, Italy and Greece broke records on Wednesday for daily new COVID-19 cases, according to government health officials.
The Greek government reported a record increase for new cases for a third consecutive day with 28,828 new cases and 72 COVID-19-related deaths.
About 64.3% of the population is fully vaccinated and 26.5% have received a booster or third dose, according to the European Centre for Disease Prevention and Control.
Health Minister Thanos Plevris announced on Wednesday that new restrictions will go into effect on Jan. 3, but Greece's Kathimerini newspaper reported that the government has decided to put them into effect at 6 p.m. local time on Thursday.
Italian health authorities recorded another record increase on Wednesday with 98,0303 new COVID-19 cases and 148 deaths.
Semi-official ANSA reported Wednesday's positivity rate is 9.5% and there are 1,185 patients in ICUs. About 51.7% of Italy's residents are fully vaccinated and 24.9% have received a booster or 3rd dose, per the ECDC.
UK health officials recorded 183,037 new cases and 57 deaths. The record-setting new case number included five days of data from Northern Ireland, which last published data on Dec. 24, according to health officials.
About 82.3% of adults in the UK have received two vaccine doses and 57.5% have received a booster, according to government data.
-ABC News' Christine Theodorou