Biden set the 100-million-dose goal in December, shortly before the U.S. authorized two vaccines against Covid-19. A lagging vaccine rollout in the Trump administration’s final weeks initially seemed to threaten Biden’s goal, but by the time Biden took office the country was administering nearly 1 million shots per day prompting questions about whether the new administration’s target was ambitious enough.

Biden has been cautious of over-promising on the pandemic response, but amid growing confidence in the vaccination effort, he last week directed states to open up vaccine eligibility to all adults by May. State officials are optimistic they can hit that mark, and some have begun or pledged to expand eligibility before then.

About 113 million doses have been administered since vaccinations began three months ago, including just over 16 million that were provided during the Trump administration. About 29 percent of all adults have received at least one dose, including two-thirds of people 65 and older, according to CDC figures.

The federal government has ordered roughly 800 million doses, split between Pfizer, Moderna and Johnson & Johnson, with enough doses available to inoculate every American adult expected by the end of May. It will take more time, however, to provide those vaccinations, with the Biden administration promising more resources to help push out the shots.

Biden in a prime-time address last week said the country could return to a sense of normalcy by July Fourth if Americans keep getting vaccinated and they continue practicing public health measures like social distancing and masking. But he warned that progress could be tenuous if Americans let down their guard.

The U.S. has seen a drop in new cases, hospitalizations and deaths since the devastating winter surge. Health officials are worried that the pace of new infections have plateaued at nearly 55,000 cases per day, even as many states including some that had been more cautious throughout the pandemic lift restrictions.

Biden’s chief medical adviser, Anthony Fauci, in a NBC News interview Thursday morning said the current daily number of new infections is “much too high to be declaring victory,” and warned that the U.S. could see another spike as states begin lifting restrictions before a significant portion of the population is vaccinated.

“It really is going to be a race between the vaccine and the potential surge,” he said.