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."

President-elect Joe Biden has applauded the COVID-19 relief bill passed Monday by the House and Senate. 

In a tweet early Tuesday morning, Biden voiced his approval of the package, but warned that Congress still has more work to do in the new year. 

"I applaud this relief package, but our work is far from over. Starting in the new year, Congress will need to immediately get to work on support for our COVID-19 plan

My message to everyone out there struggling right now: help is on the way," he tweeted.

The Chairman of the Joint Chiefs of Staff Gen. Mark Milley and other top military officials received Pfizer's COVID-19 vaccine Monday, according to a Joint Staff spokesman. 

Milley's team tweeted photos of him, Vice Chairman Gen. John Hyten, and Senior Enlisted Advisor Ramón Colón-López Monday, each with a needle in his arm. 

“Today I, along with the Vice Chairman and the SEAC, received the #COVID19 vaccine. It’s my distinct honor to represent the Joint Force in this capacity. This vaccine is safe and effective and will protect our force as we work to protect American citizens," Milley was quoted as saying in the official tweet. 

Chief of Naval Operations Adm. Michael Gilday also tweeted a photo of himself receiving the vaccine on Monday. 

"By maximizing vaccination among our force and maintaining our mitigation measures of physical distancing, mask-wearing, and handwashing, we will begin the return to normal. Safe and healthy is the goal for 2021! Together, we will make this happen," the tweet read.

-ABC News' Matt Seyler