"Let me be deadly earnest with you: We aren't at the finish line. We still have a lot of work to do. We're still in a life and death race against this virus," Biden said in remarks at the White House.

The president warned that " new variants of the virus are spreading and they're moving quickly. Cases are going back up, hospitalizations are no longer declining." He added that "the pandemic remains dangerous," and encouraged Americans to continue to wash their hands, socially distance and wear masks.

Biden added that while his administration is on schedule to meet his new goal of distributing 200 million doses of the vaccine during his first 100 days, it will still take time for enough Americans to get vaccinated to slow the spread of the virus.

But he expressed hope that his Tuesday announcement, that every adult will be eligible by April 19 to sign up and get in a virtual line to be vaccinated, will help expand access and distribution of the vaccine. Some states already had begun moving up their deadlines from the original May 1 goal.