Dr. Anthony Fauci, Health and Human Services Secretary Alex Azar and National Institutes of Health Director Francis Collins were vaccinated Tuesday with the newly authorized Moderna vaccine, which the NIH helped develop.

Azar said to the NIH staff, “This is one of your finest accomplishments.”

Hours before getting vaccinated, Dr. Anthony Fauci told ABC News' "Good Morning America" Tuesday, “I want to symbolize to people the importance that everyone gets vaccinated who can get vaccinated.”

Fauci will receive the Moderna vaccine, which the National Institutes of Health helped develop. Fauci is director of the National Institute of Allergy and Infectious Diseases, which is part of the NIH.

Fauci said the general population will likely start receiving vaccines at the end of March or beginning of April -- but it’s unclear how long that process will take.

“It may take two, three, four months or more before you get everyone vaccinated that wants to be vaccinated,” Fauci said.

In the wake of an uptick in cases in England linked to a new COVID-19 variant, Fauci said he “would not be surprised” if the variant is in the U.S.

“When you have this amount of spread within a place like the U.K., you really need to assume that it’s here already. And certainly is not the dominant strain, but I would not be surprised at all if it’s already here," he said.

The reproduction rate of the new variant is 0.4 higher than other known strains, Dr. Maria Van Kerkhove, the World Health Organization’s COVID-19 technical lead, said Monday. That means the number of people an infected individual transmits to increases from 1.1 to 1.5 with the new variant.

There’s "zero evidence" that the new variant causes more severe disease, said Dr. Mike Ryan, executive director of the WHO’s Health Emergencies Programme.

BioNTech CEO Ugur Sahin is confident that the pharmaceutical company's coronavirus vaccine will work against the new U.K. variant of the virus.

"We don't know at the moment if our vaccine is also able to provide protection against this new variant," Sahin told a news conference Tuesday, after the vaccine was approved for use in the European Union. "But scientifically, it is highly likely that the immune response by this vaccine also can deal with the new virus variants."

He explained that the proteins on the U.K. variant are 99% the same as the ones on the original strain, so BioNTech has "scientific confidence" that its vaccine will be effective on the variant as well.

Still, more studies need to be done.

"But we will know it only if the experiment is done and we will need about two weeks from now to get the data," Sahin said. "The likelihood that our vaccine works ... is relatively high."

Los Angeles officials arrested over 60 people involved in underground parties over the weekend.

In a statement, the Los Angeles County Sheriff’s Department said the parties were considered superspreader events, as they violated COVID-19 health protocols.

Around 10:45 p.m. Saturday, the Los Angeles Police Department responded to an underground party event in Los Angeles and found two people shot. One of the victims was pronounced dead at the scene, according to a statement from the LASD.

Then, at around 12:30 a.m. Sunday, officers responded to another underground party in Compton, where they arrested 67 people: 61 adults and six juveniles. One firearm was recovered.

A third underground party, located in Los Angeles, was shut down by the LAPD after a shooting took place.

"Sheriff Alex Villanueva has made it clear he will seek out and take law enforcement action against all underground party events occurring anywhere within Los Angeles County, who fall under the Health Orders of the County’s Department of Public Health," the LASD said in their statement. "The goal of these enforcement actions is to reduce the spread of COVID-19 and the risk to our vulnerable populations."

California’s stay-at-home orders -- currently in effect for 98% of the state’s population -- will likely be extended, Gov. Gavin Newsom said.

A three-week stay-at-home order was issued in a region of California when it fell below 15% intensive care unit capacity. The stay-at-home order can only be lifted when ICU capacity returns to above 15%.

Two of the five regions, Southern California and San Joaquin Valley, currently have 0% capacity.

The Bay Area and the Greater Sacramento area also under a stay-at-home order. Northern California is the state’s only region not under the order.

California has 17,190 coronavirus patients in hospitals -- a 63% increase in the last two weeks.

California has deployed 607 state workers to 75 health care facilities in 24 counties that were requesting extra assistance. Newsom said he has asked the Department of Defense for 10 teams of 20 health care workers, and he is also asking a team that’s been working in Imperial County to extend its stay until the end of January.

ABC News’ Matt Fuhrman contributed to this report.