By Veronica Stracqualursi, CNN

(CNN) -- Health and Human Services Secretary Alex Azar said Wednesday that he has met with President-elect Joe Biden's transition team and pledged a smooth transition, a rare recognition of the coming transfer of power from a top member of President Donald Trump's administration.

At a time when the coronavirus pandemic is surging across the nation, Azar predicted on CNN's "New Day" that 20 million people will be vaccinated in "the next several weeks." He said the Trump administration is negotiating with Pfizer to secure additional doses of its vaccine and said the administration will "use every power" under the Defense Production Act to aid private companies with the massive logistical requirements of vaccinating the country.

"I have already met with the Biden transition team. We want to make sure they get everything that they need," Azar told CNN's Alisyn Camerota, adding that he would be in touch with Biden's pick to lead HHS, California Attorney General Xavier Becerra, as "appropriate."

"I want to ensure that any transition is as smooth, as professional as possible, because we are about ensuring the health and well-being of the American people and that's what matters to me," Azar said.

His comments come at a critical time in the pandemic. Covid-19 cases and hospitalizations are surging across the US, but significant progress is being made on vaccines. The United Kingdom has already started rolling out the Pfizer/BioNTech vaccine, becoming the world's first nation to begin vaccinating its citizens, and a US Food and Drug Administration advisory committee is set to meet Thursday to review it, a key step in the emergency use authorization process.

Asked about initial reports out of the United Kingdom, including whether people with a "significant history of allergic reactions" should not receive the Pfizer/BioNTech vaccine, Azar told CNN that the FDA would look at the data and speak with the UK regulators, assuring that the agency "is going to not cut any corners."

"We want to make sure that any vaccine that comes out in America has the full gold standard stamp of approval of the FDA career people," Azar said.

Once a vaccine is approved by the FDA, the federal government would then authorize shipment of the vaccine within 24 hours and directly ship them to "wherever the governors have told us where they want it to go," Azar told CNN.

The initial focus will be health care workers and nursing home patients, according to Azar.

"Twenty million people should get vaccinated in just the next several weeks, and then we'll just keep rolling out vaccines through January, February, March as they come off the production lines," Azar said.

The coronavirus pandemic is averaging more than 200,000 new coronavirus cases a day over the past week, while record numbers of people are hospitalized with the virus. As of Wednesday morning, more than 286,000 people have died and more than 15.1 million people have been infected, according to data from Johns Hopkins University.

Negotiations with Pfizer

Azar also responded to reports that the Trump administration declined a deal over the summer for more of the Pfizer vaccine -- before it was proven effective in clinical trials -- than its initial order of 100 million doses. Without a firm delivery date or quantity -- and with other vaccine candidates in the works as well -- the US held off on placing the order for additional doses, but the decision, first reported by The New York Times, has mounted concerns that the company would be unable to fulfill any additional US order until June because of their commitments to other countries.

"We guaranteed the purchase of 100 million doses of the Pfizer vaccine before they had initiated phase three clinical trials. They were not willing to give us a concrete date to commit to produce and deliver additional vaccines, so we secured a 500 million option for additional," Azar said.

Azar said that the federal government is negotiating with Pfizer, but would not go into further detail, only adding that "we have options that go up to 500 million." He also said the administration is negotiating with other pharmaceutical manufacturers about additional vaccines.

"We have, over the last couple of months, been working with Pfizer to secure their commitment and agreement to deliver additional doses under our options, by a date certain. We're very optimistic that will happen, but I want the American people to know we will use every power we have under the Defense Production Act to make sure the American people get what they need," he said, suggesting that the government can provide raw materials and equipment to companies to help with the rollout. It's unclear, however, whether the administration could use the act to force companies to provide Americans with the coronavirus vaccine before other nations.

Azar defends White House Christmas parties

Despite the rising Covid-19 cases in the US, the White House has continued to flout Centers for Disease Control and Prevention guidelines for size restrictions by hosting holiday parties.

The Trump White House has already been the epicenter of at least three Covid-19 outbreaks among staff and attendees of the gatherings they've hosted, and Trump campaign lawyer Jenna Ellis recently tested positive for Covid-19 and had attended a Christmas party designated for senior staff on Friday.

Asked if he was comfortable with the White House still hosting such events amid the pandemic, Azar told CNN he "felt safe" at a recent White House Christmas party he attended.

"I actually have already attended one of them, and individuals -- most of the individuals -- around me were wearing masks. We worked to keep distance. There was dramatically lower number of people than in past years. So I felt comfortable there. I felt safe. I wore my mask, of course, at all times," he said.

He encouraged Americans "no matter what the setting" to "wash your hands, watch your distance, wear your face coverings if you can't watch your distance, especially do not let your guard down in indoor settings."