The milestone was reached only five days after the US, the
world's wealthiest and hardest-hit nation, recorded 400,000 deaths from the
disease.
Biden 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.
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.
White House Chief of Staff Ron Klain said Biden's
administration would "take responsibility" for the trajectory. Former
president Donald Trump came under frequent criticism for perceived federal
inaction in combating the virus.
"We're going to set up these federal vaccination
centers to make sure that in states that don't have enough ... we fill those
gaps," Klain told the NBC News show "Meet the Press."
"We need more vaccine, we need more vaccinators and we
need more vaccine sites."
The US caseload remains by far the world's 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.
Xavier Becerra, Biden's secretary of health and human
services nominee, likened the Covid-19 trajectory under Trump to a plane about
to crash.
"We've got to pull it up and you aren't going to do
that overnight, but we'll pull it up -- we have to pull it up," he told
CNN.
"Failure is not an option here."
Last week, 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.
The US has now recorded 25,003,695 million cases, according
to the Baltimore-based university's coronavirus tracking website -- though with
testing shaky at the start of the pandemic, the real toll is believed to be
much higher.