Biden, who has detailed the first national strategy against Covid-19, warned that deaths may reach 600,000 before vaccines begin to create immunity on a large scale.
He has made fighting the coronavirus a priority and is pushing for Congress to approve a $1.9-trillion relief package that would include billions of dollars to boost vaccination rates.
Biden has said he wants 100 million people vaccinated within his first 100 days in office, and he has called for Americans to wear masks for 100 days.
Earlier today, Biden's chief of staff, Ron Klain, said there was no distribution plan for the coronavirus vaccine set up by the Trump administration as the virus raged in its last months in office.
"The process to distribute the vaccine, particularly outside of nursing homes and hospitals out into the community as a whole, did not really exist when we came into the White House," Klain said on NBC's "Meet the Press."
Biden plans to partner with state and local governments to establish vaccination spots in conference centers, stadiums and gymnasiums. The new administration will also deploy thousands of clinical staff from federal agencies, military medical personnel and pharmacy chains to increase vaccinations, and make teachers and grocery clerks eligible.
Vaccination programs lagged far behind the Trump administration's target of 20 million Americans inoculated by the end of 2020.
"We've seen this factor all over the country where millions of doses have been distributed, but only about half have been given out," Klain said.
"So the process of getting that vaccine into arms - that's the hard process. That's where we're behind as a country. That's where we're focused in the Biden administration - on getting that ramped up."
Countries around the world are in a race against time to get their populations inoculated before the coronavirus mutates into a strain that could resist newly approved vaccinations.
Vivek Murthy, Biden's nominee for surgeon-general, told ABC News on Sunday that 100 million doses in 100 days was "a floor, not a ceiling" and cautioned about new strains.
"The variants are very concerning," Murthy told the network.
"It's up to us to adapt and stay ahead," he added.
The US caseload remains by far the highest in absolute terms.
India, where the population is about four times larger than in the US, has the second-highest caseload with about 10.6 million cases, according to Johns Hopkins.
After the first Covid-19 case was reported in the US in January 2020 it took until late April for the figure to pass one million. The overall number of cases has followed an almost exponential curve upwards since then.
Last week, Baltimore-based Johns Hopkins announced more than 400,000 people in the US had died from Covid-19, a grim marker that came one day before Biden's inauguration.