COVID-19 updates: Elizabeth Warren tests positive

"Saturday Night Live" won't have an audience and will limit its cast and crew at tonight's taping "out of an abundance of caution," the show announced, as New York sees a spike in COVID-19 cases.

"Due to the recent spike in the Omicron variant and out of an abundance of caution, there will be no live audience for tonight’s taping of 'Saturday Night Live' and the show will have limited cast and crew," tweeted the show, which films at 30 Rockefeller Plaza in Manhattan.

"The show continues to follow all government safety guidelines in addition to a rigorous testing protocol," it added.

Charli XCX was slated to be the musical guest but is no longer performing due to the limited crew, the singer announced on Twitter, saying she was "devastated and heartbroken."

Paul Rudd is the host of the episode, which is the last one of 2021.

The move comes as New York state broke its record for daily COVID-19 cases two days in a row. Several shows in New York City, from Broadway productions to the Rockettes, also have had to cancel performances due to COVID-19 cases.

-ABC News' Joshua Hoyos

Harvard University is shifting to remote learning for the first three weeks of January due to a "rapid" rise in COVID-19 cases locally, school officials announced Saturday.

"Please know that we do not take this step lightly," school leaders said in an update to students. "It is prompted by the rapid rise in COVID-19 cases locally and across the country, as well as the growing presence of the highly transmissible Omicron variant." 

Only students with previous authorization will be allowed to remain on campus. Some programs, like essential in-person laboratory and patient-centered work, will continue as normal, the school said.

"We are planning a return to more robust on-campus activities later in January, public health conditions permitting," the school officials said. 

Several universities, including Princeton, NYU and Cornell, have shifted final exams remote and canceled events in recent days due to spikes in COVID-19 cases.

-ABC News' Arielle Mitropoulos

Enforcement of the Biden administration's vaccine-or-test mandate for private companies with more 100 employees will be delayed by a month, officials said.

The Labor Department’s Occupational Safety and Health Administration announced the change Saturday, a day after a federal appeals court lifted a stay on the rule, allowing it to proceed. 

Previously, the mandate required companies to enforce masks among unvaccinated employees beginning Dec. 6, and either see proof of vaccination or begin testing workers weekly by Jan. 4. 

The new deadlines for compliance are now Jan. 10 and Feb. 9, respectively, OSHA said.

-ABC News' Anne Flaherty

Nearly 22,000 positive COVID-19 test results were reported in New York state in the last 24 hours, according to Gov. Kathy Hochul's office -- breaking a single-day record set the day before. 

The 21,908 positive COVID-19 test results are out of 290,930 results reported -- for a 7.53% positivity rate.

Demand for testing also continues to rise, with about 27,000 more people getting tested on Friday.

"This is not like the beginning of the pandemic. We are prepared for the winter surge because we have the tools at our disposal," Hochul said in a statement. "Getting vaccinated, getting the booster and wearing a mask are critical to avoiding getting seriously ill from COVID-19, so don't take a chance."

-ABC News' Joshua Hoyos