Coronavirus updates: State reports over 49,000 new cases, 468 new deaths

The U.S. has surpassed 300,000 new daily COVID-19 cases for the first time, according to The COVID Tracking Project.

There were 310,080 new cases reported Friday. New Jersey and California both "greatly influenced" the surge in cases, the tracker said. New Jersey reported nearly 20,000 probable COVID-19 cases and California had over 50,000 cases.

Sixteen states also reported record COVID-19 hospitalizations this week, the tracker said: Alabama, Arizona, Arkansas, California, Delaware, Georgia, Maine, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia and West Virginia.

Hospitalizations in California and Arizona in particular are increasing at an alarming rate, it noted.

A new study says Pfizer's vaccine is likely to work against the new, rapidly-spreading variants of COVID-19.

Dr. Pei-Yong Shi of the University of Texas Medical Branch in Galveston told ABC News this is "the first study to show that one of the most prominent mutations in the fast-spreading UK and the South African strain ... doesn't affect the neutralizing activity of the current vaccine." 

Some of the antibodies produced by the vaccine "may be weakened by a single mutation, but others will remain active," he said, which he believes will continue to provide protection from the variants.

Although Shi only studied Pfizer's vaccine, he said the results "can be generated to the other vaccine platforms," including Moderna and AstraZeneca.

The vaccines “are all based on the same sequence of the spike protein,” he said, “so I will not be surprised that it will be it will be the same result." 

While the U.K. variant that’s been confirmed in several U.S. states appears to spread more rapidly, there’s no evidence that it’s more deadly.

ABC News’ Sony Salzman contributed to this report.

Florida State Rep. Mike Caruso, a Republican who represents Boca Raton, told ABC News he is concerned about people who attended the U.S. Capitol riot coming back to his district -- where there’s a high elderly population -- and spreading COVID-19. 

"I would ask them to quarantine when they do come back and to go get tested," Caruso said, adding that they should be tested before flying home.

ABC News’ Sasha Pezenik contributed to this report.

President-elect Joe Biden will get his second vaccine dose in public on Monday “to continue to instill confidence in the vaccine’s safety and efficacy,” said incoming White House press secretary Jen Psaki.

This will be 21 days after Biden received the first dose, she said.

When Vice President-Elect Kamala Harris receives her second dose, it will also be in public, she said.

Psaki added, “The Biden-Harris transition team today started to vaccinate incoming members of the administration. Up to 35 individuals will be vaccinated.”

“These individuals are people who will be in close proximity to the President or Vice President, who are critical members of the National Security team or are Cabinet nominees in the line of succession to the presidency,” she said. “These vaccinations are being conducted now so that these individuals can complete their inoculation shortly after January 20. The vaccine being used for this purpose is coming from supplies previously allocated to the White House medical unit.”

ABC News’ John Verhovek and Molly Nagle contributed to this report.