The U.S. government has purchased an additional 500,000 doses of Evusheld, AstraZeneca's monoclonal antibody drug, to be given before exposure to COVID-19, the company announced. This is on top of the 700,000 Evusheld doses already purchased.

White House officials previously said over 500,000 doses would be stockpiled in January and "significantly more" would be purchased by March."

Evusheld was authorized in December 2021 and is the first monoclonal therapy meant to be used in advance of an eligible person's exposure to COVID-19.

However, it's not meant for a wide group of people: this therapy is only authorized for immunocompromised people who may not have developed an optimal immune response to their vaccine. This therapy is also for people with a history of severe adverse reactions to a COVID-19 vaccine and thus aren't recommended to get vaccinated. 

Evusheld is not authorized as a way to treat COVID-19 after testing positive.

-ABC News' Sasha Pezenik

More than 15 million new COVID-19 cases were reported globally last week, according to the World Health Organization.

"By far the most cases reported in a single week, and we know this is an underestimate," WHO Director-General Dr. Tedros Adhanom Ghebreyesus said Wednesday.

He said this "huge spike" is driven by omicron.

"While omicron causes less severe disease than delta, it remains a dangerous virus, particularly for those who are unvaccinated," Tedros warned.

WHO officials said new vaccines may be needed for different variants, and until those vaccines are developed, the current vaccines may need to be updated. 

-ABC News' Christine Theodorou

The White House is considering making "more high-quality masks" available to all Americans, according to White House COVID-19 coordinator Jeff Zients.

"We're in the process right now of strongly considering options to make more high-quality masks available to all Americans," he said at Wednesday's briefing.

-ABC News' Cheyenne Haslett

Deaths in the U.S. are on the rise. The average now stands at more than 1,600 new COVID-19-related fatalities each day -- up by about 48% in the last two weeks, according to federal data.

Out of the 3,220 U.S. counties, just 26 counties are not reporting high transmission, according to federal data.

In the last week alone, the U.S. has reported more than 5.2 million new cases -- that averages out to nearly nine Americans testing positive for COVID-19 every second.

Rhode Island is reporting the nation's highest new case rate, while California is now averaging more than 100,000 new cases every day -- a pandemic high for the Golden State.

But, according to experts, the surging national case numbers may not be indicative of what is happening in every region, and the nation's overall continued increase does not necessarily mean that some areas will not see a decline.

-ABC News' Arielle Mitropoulos