Seventy-five percent of those eligible (12 years and older) have received at least one dose of a COVID vaccine, the White House's COVID-19 data director Cyrus Shahpar posted on Twitter Friday.

Calling the statistic a "milestone," Shahpur also tweeted, "Let's add more!"

The White House said Friday millions of federal contractors must get fully vaccinated against the coronavirus by Dec. 8.

The announcement came in a document issued Friday by the White House’s budget office, the Office of Management and Budget, following up on an executive order President Joe Biden signed Sept. 9 that mandated vaccinations for federal contractors, Reuters reported.

The formal guidance also says that after Dec. 8 “all covered contractor employees must be fully vaccinated by the first day of the period of performance on a newly awarded covered contract.”

An OMB spokesperson told ABC News that “millions” of people would be covered but didn’t share more exact numbers.

Earlier this month, the White House said that federal government employees and contractors will now be required to be fully vaccinated against COVID-19, and the Occupational Safety and Health Administration will create a rule for private businesses with 100 or more employees to require their employees to be vaccinated or undergo weekly testing.

-ABC News' Ben Gittleson, Molly Nagle, Sarah Kolinovsky, and Justin Gomez

National Nurses United, the nation’s largest union of registered nurses, is lauding CDC director Rochelle Walensky’s inclusion of front-line and health care workers in her recommendations for who may now get a third Pfizer booster dose -- a decision which overruled the agency’s independent panel conclusion.

The CDC’s advisory group had rejected the idea of third Pfizer doses for “high risk” workers like nurses and teachers, saying that without further data it wasn’t comfortable with automatically adding younger, healthier people simply by occupation.

The nurses' union urged Walensky to bypass what her advisory panel had said -- which is what she ultimately did.

“Nurses across the country are beyond relieved today to wake up to the news that CDC Director Rochelle Walensky prioritized the health and safety of health care and other essential workers most at risk of contracting Covid-19,” NNU president Deborah Burger told ABC in a statement Friday.

“It takes courage to do the right thing, especially when it involves going against the CDC’s own advisory panel," Burger added. "We applaud this bold decision-making that prioritizes the health and safety of workers on the front lines of this ongoing crisis, and we know that her decision will absolutely save lives.”

Walensky however, insisted that she did not overrule the CDC’s advisory panel’s decision on booster shots for at-risk, front-line workers. She defended the decision as a “scientific close call” saying that she would advocate for the boosters if she was in the room.

"I want to be very clear that I did not overrule … the advisory committee," she said. “I listened to the votes. I listened to the comments on the vote and this was a scientific close call ... It was my call to make. If I had been in the room, I would have voted 'yes.'"

She also said that boosters were not a solution for ending the pandemic.

"I want to be clear we will not boost our way out of this pandemic. Infections among the unvaccinated continue to fuel this pandemic rise, resulting in a rising number of cases, hospitalizations and deaths where people are in vaccinated," Walensky said. 

-ABC News' Sasha Pezenik and Matthew Vann

On the heels of pharmacy retail chain Walgreens' announcement that it is now ready to give third booster doses of the Pfizer vaccine to newly eligible groups, CVS announced it too will be ready "later today."

-ABC News' Sasha Pezenik