Coronavirus updates: US reports nearly 300,000 new cases in all-time high

The United States reported 3,725 deaths on Tuesday, breaking the previous single-day total of 3,656 set on Dec. 16, according to data compiled by Johns Hopkins University.

The current numbers may not give the complete picture as the holidays have significantly impacted data, with many states having not reported numbers or have given incomplete updates.

December has already been determined to be the worst month on record for cases, hospitalizations and deaths, surpassing the high numbers seen in April.

-ABC News' Ahmad Hemingway contributed to this report.

A COVID-19 vaccine created by AstraZeneca and the University of Oxford has been approved for emergency use in the United Kingdom.

Roll out will begin Jan 4, Health Secretary Matt Hancock said.

The U.K. Department of Health and Social care announced that it has accepted the recommendation from the Medicines and Healthcare products Regulatory Agency (MHRA) to authorize the vaccine for use.

"This follows rigorous clinical trials and a thorough analysis of the data by experts at the MHRA, which has concluded that the vaccine has met its strict standards of safety, quality and effectiveness," the Department of Health and Social care said in a press release.

It is the second vaccine approved for use in the U.K. following the rollout of the Pfizer/BioNTech vaccine.

The National Health Service will prioritize giving the first doses of the newly approved vaccine to those in the most high-risk groups.

The vaccine will be given in two doses, with four to 12 weeks between doses, the U.K.-based pharmaceutical company said.

COVID-19 hospitalizations have hit a record high in the U.S.

There are 124,686 people currently hospitalized, according to the COVID Tracking Project. 

There were also 194,512 new cases and 3,283 deaths reported on Tuesday, though the tracker noted that there are delays in both figures due to the holidays.

"Current hospitalizations remains our most stable state-reported metric during holiday disruptions, and it will be our best guide to reality until states work through all Christmas + New Year’s backlogs," it said.

The U.S. Dept. of Health and Human Services revised its earlier expectation that 20 million coronavirus vaccine doses would be administered by Christmas, the agency said in a statement Tuesday.

It now expects to hit 20 million vaccines into the first week of January, an Operation Warp Speed spokesperson said in a statement.

"These doses are being distributed at states’ direction to the American people as quickly as they are available and releasable," OWS spokesman Michael Pratt said in a statement.

Pratt added that the lag in reporting vaccination doses administered is expected.

-ABC News' Anne Flaherty contributed to this report.