Dr. Anthony Fauci said vaccines will be the "answer" to the pandemic, but they come as America remains in "very, very difficult times."
"I don't want to get ahead of the line, but I want to make sure we demonstrate to the American people that it is safe to take," Biden told reporters.
The infectious disease expert acknowledged his projected timeline is subject to change, depending on the efficiency of early vaccine rollouts across the country and how many people choose to receive the immunization.
"This president has done about as good a job with this rollout as I did throwing out that first pitch at the Nationals game," McKinnon's Fauci joked.
According to data from the COVID Tracking Project, cases in New York have continued to rise over the past few weeks, placing the state close to its previous peak numbers from April.
The head of the National Institute of Allergy and Infectious Diseases said it will take a while to achieve herd immunity if a substantial proportion of the population is not vaccinated.
The top scientist's warning comes as the U.S. has logged its most ever coronavirus-related deaths over a seven day period.
President-elect Biden and three former presidents have said they would get vaccinated publicly amid a climate of fear surrounding the safety of the shots.
"You can be De Niro or Pacino," New York Governor Andrew Cuomo told Dr. Anthony Fauci. "Which one do you want to be?"
"I think it could be even more of a challenge than what we saw with Thanksgiving," Dr. Fauci stated.
In June, Fauci said it was possible America could reach 100,000 cases a day, but he called America doubling that amount "predictable."
"This accomplished team of leaders will bring the highest level of integrity, scientific rigor, and crisis-management experience to one of the toughest challenges America has ever faced," Biden said.
The current number of hospitalizations topped 100,000 this week, as the U.S. also recorded its highest daily case count on record.
Dr. Anthony Fauci told Newsweek: "If people take the vaccine, we could go a long way to really diminishing dramatically" cases by Q3 2021.
The agency recommends wearing a mask in all indoor spaces, a day after Joe Biden said he would encourage Americans to commit to 100 days of masks on his first day in office.
"People were less willing to change their behavior than any other day during the pandemic," Laura Schewel, founder of StreetLight Data, told the Associated Press.
The top U.S. infectious disease expert told NBC's "Today" program that he accepted the post "on the spot."
On post-Thanksgiving COVID figures, Dr. Anthony Fauci told Newsweek: "I hate to say that but it's the truth and the reality.
Hospitalizations for the new coronavirus have surpassed 100,000 nationwide as public health experts predict the situation will worsen in the coming weeks.
"You know, in all fairness to so many of my U.K. friends, they kind of ran around the corner of the marathon and joined this in the last mile," the infectious disease expert said.
Fox News host Tucker Carlson on Wednesday insisted that Dr. Anthony Fauci would "never work in public policy again" in a "well functioning society" over his early comments about China's information sharing during the initial outbreak of COVID-19.
"I promise you that when it's been made for people who are less at risk, I will be taking it," the former president said.
"As long as you are susceptible, you are part of the problem, not part of the solution," the nation's top infectious disease expert said in an interview with Facebook boss Mark Zuckerberg Monday.
"We don't want to frighten people but that's just the reality," Dr. Anthony Fauci said regarding the trajectory of the pandemic.
Dr. Anthony Fauci, the nation's top infectious disease expert, didn't see his daughters at Thanksgiving and said he likely won't be celebrating in-person with them at Christmas, either.
Biden COVID adviser Dr. Celine Gounder pointed out that healthcare workers are "already exhausted" after fighting the pandemic for months.
While state and local leaders have issued lockdown restrictions against large gatherings in people's homes, some people are ignoring them.
"I will have it with my wife alone in our house, with our three daughters Zooming in," the top U.S. scientist said about his own holiday plans during the coronavirus pandemic.
More than four in 10 Americans say they won't get the COVID vaccine when it becomes available. Big problem: Even a highly effective vaccine won't do much to rein in the pandemic if enough people can't be persuaded to get the shot.